ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Rob Spence on July 15, 2019, 05:39:48 pm

Title: Replacing my DSP
Post by: Rob Spence on July 15, 2019, 05:39:48 pm
I have been using a Sabine Nav 480 for a long time. It has served me very well but I think the time has come to replace it as Sabine is no more and I worry about a failure these days. I will likely keep the Sabine racked as a spare.

I use it with subs and two pair of EV QRX-212s running in bi-amp mode.

I got my original settings for it from EV way back when. I actually sent the unit to an engineer at EV and he derived the settings for me from their reference DSP.

I have two primary configurations I use. A standard stereo crossover with HF, MF and mono sub out. The second one is similar except I use 3 inputs for Aux fed subs.

The new DSP is a dbx DR360.
I found a set of parameters for a DR260 that Evan Kirkendal posted. Does anyone know if DR260 settings will work with a DR360? I know that setting are not always portable due to different DSP implementations.

Alternatively, is there a current contact at EV who might have settings for the DR360? I didnít find anything on the EV website besides their own DSPs.

I suppose I could feed pink noise into a channel of my old DSP and a channel of the new one and use SMAART to make the new one the same as the old. I may do that anyway but starting with something close should make it easier.

Thoughts?

Thanks
Title: Re: Replacing my DSP
Post by: David Winners on July 15, 2019, 07:07:54 pm
When I was getting my QRx rig up and running, this is the email address I got settings from.

I did have to jump up and down on their Facebook page to get a response.

Audiosupport@us.bosch.com
Title: Re: Replacing my DSP
Post by: David Sturzenbecher on July 15, 2019, 09:02:16 pm
I have been using a Sabine Nav 480 for a long time. It has served me very well but I think the time has come to replace it as Sabine is no more and I worry about a failure these days. I will likely keep the Sabine racked as a spare.

I use it with subs and two pair of EV QRX-212s running in bi-amp mode.

I got my original settings for it from EV way back when. I actually sent the unit to an engineer at EV and he derived the settings for me from their reference DSP.

I have two primary configurations I use. A standard stereo crossover with HF, MF and mono sub out. The second one is similar except I use 3 inputs for Aux fed subs.

The new DSP is a dbx DR360.
I found a set of parameters for a DR260 that Evan Kirkendal posted. Does anyone know if DR260 settings will work with a DR360? I know that setting are not always portable due to different DSP implementations.

Alternatively, is there a current contact at EV who might have settings for the DR360? I didnít find anything on the EV website besides their own DSPs.

I suppose I could feed pink noise into a channel of my old DSP and a channel of the new one and use SMAART to make the new one the same as the old. I may do that anyway but starting with something close should make it easier.

Thoughts?

Thanks

Rob,
If there is flexibility, I would really recommend a processor from EV that does FIRs for those boxes. Something like the EV DX46.  In my experience it does take them to the next level. Or look at the TGX amps with processing inside.
Title: Re: Replacing my DSP
Post by: John Schalk on July 16, 2019, 08:52:45 am
The band I work for has a QRx153 over PX2181 rig and they use a DriveRack, but I'm not sure of the model.  The band leader has told me that their former BE SMAART'd the rig and tweaked the stock settings that they got from EV.  Apparently they were close, but quite right. 
Title: Re: Replacing my DSP
Post by: Dave Pluke on July 16, 2019, 03:11:10 pm
The new DSP is a dbx DR360.
I found a set of parameters for a DR260 that Evan Kirkendal posted. Does anyone know if DR260 settings will work with a DR360? I know that setting are not always portable due to different DSP implementations.

Can settings from a DR260 be imported to a VENU360?  No - they are different beasts.

You can manually transfer those settings, though.  Have both programs running (with Driveware 260 in off-line mode) to make things easier.  Should get you close.  Fine tune from there.

Dave
Title: Re: Replacing my DSP
Post by: Rob Spence on July 16, 2019, 03:45:01 pm
Can settings from a DR260 be imported to a VENU360?  No - they are different beasts.

You can manually transfer those settings, though.  Have both programs running (with Driveware 260 in off-line mode) to make things easier.  Should get you close.  Fine tune from there.

Dave

I donít care about importing settings. I will enter them myself.
My concern is if the Venue360 implements filters such that settings for a DR260 will work.

By the way, I do not have a 260.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 16, 2019, 03:51:14 pm
Rob,
If there is flexibility, I would really recommend a processor from EV that does FIRs for those boxes. Something like the EV DX46.  In my experience it does take them to the next level. Or look at the TGX amps with processing inside.

No flex here. I have a dbx Venue360 to replace my NAV480. Turns out I never really used the 4th input much or the extra 2 outputs.
Title: Re: Replacing my DSP
Post by: Ivan Beaver on July 16, 2019, 04:41:34 pm
I have heard (but cannot confirm) that on some models of DBX processors the same numbers will result in different actual settings.

This is typical for many DSPs.

The best way is to do a transfer function of your current Sabine and then adjust the DBX as needed.

I have seen some DSPs be almost an octave off in xover settings and the filter width be twice or half of another model.

DO NOT assume the numbers will give you the same result
Title: Re: Replacing my DSP
Post by: Dave Pluke on July 17, 2019, 12:49:49 pm
By the way, I do not have a 260.

You won't need one to run the Driveware 260 program on a computer and import the settings file.

Ivan's concerns notwithstanding, I'd enter the settings manually then use an RTA to verify.

Dave
Title: Re: Replacing my DSP
Post by: Frank Koenig on July 17, 2019, 02:40:02 pm
...use an RTA to verify.

Why stop there? Use a dual channel analyzer and really verify -- magnitude and phase. An all-pass filter, or any non-minimum phase behavior, won't show up on an RTA. I would always want to do a final verification, including an acoustic one with a mic, no matter how sure I am of the settings. All the info may be perfect but I can still find a way to screw it up. Check the limiters with a voltmeter while you're at it.  And then sit back, play some nice music, and have a beer (or something) for the final verification  8)

--Frank
Title: Re: Replacing my DSP
Post by: Rob Spence on July 18, 2019, 12:22:38 am
Today I fired up the dbx Venue360 and started configuring.
Of course it didnít have my speakers in its library but it did have similar amps (I use plx3402, 1602 & I chose 3602, 1802). I picked SRX722 as similar to my QRX212s and ran the configuration wizard. I then edited the crossover, PEQ & Limiter according to settings I got from EV (thanks for the email... it bounced but included the correct one - Technical.Support@us.bosch.com. They replied within a day!). I then compared it to the settings Evan K posted years ago and tomorrow will compare to what I had loaded into the Sabine (rebranded Xillica). Then, I will hook up my SMAART rig and compare the two and adjust as needed.

One thing I noticed on the dbx unit was a reduced level of precision on PEQ and crossover settings from what I am used to and the numbers EV gave me for an Ashley Protea.

It sure was nice to sit in my easy chair with my MacBook and connect via WiFi to do the configuration.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 18, 2019, 12:29:03 am
Why stop there? Use a dual channel analyzer and really verify -- magnitude and phase. An all-pass filter, or any non-minimum phase behavior, won't show up on an RTA. I would always want to do a final verification, including an acoustic one with a mic, no matter how sure I am of the settings. All the info may be perfect but I can still find a way to screw it up. Check the limiters with a voltmeter while you're at it.  And then sit back, play some nice music, and have a beer (or something) for the final verification  8)

--Frank

Yes, using the dual channel analyzer is the plan. Setting the rig up to listen will be a big job but you are right, it has to be done.
Perhaps left channel through old DSP and right to new and pan back and forth or something like that?

The beer, yup!
Title: Re: Replacing my DSP
Post by: David Sturzenbecher on July 18, 2019, 01:36:06 pm
Yes, using the dual channel analyzer is the plan. Setting the rig up to listen will be a big job but you are right, it has to be done.
Perhaps left channel through old DSP and right to new and pan back and forth or something like that?

The beer, yup!

No, not like that. You donít need to set up the speakers either.  You need to take the transfer function of just the two DSP boxes. So your reference channel is what is going into the DSP and your measurement channel is what is coming out of each DSP output.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 18, 2019, 02:38:51 pm
No, not like that. You donít need to set up the speakers either.  You need to take the transfer function of just the two DSP boxes. So your reference channel is what is going into the DSP and your measurement channel is what is coming out of each DSP output.

What I did today was put pink noise (via SMAART) into the inputs of both DSPs.
I then used my old one for a reference and the new one as the measurement channel (I have a 2 channel SMAART setup with V7) on a MacBook.

The LF section looks great. Flat with good coherence. The HF is good to 2KhZ but then wacky after that. I am not sure how to move on from here.

My ignorance and lack of experience with SMAART is showing.

I have a screen shot of the HF capture. I will try and post it.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 18, 2019, 02:44:06 pm
Here is (I hope) a screen shot of the HF as seen in SMAART.
Title: Re: Replacing my DSP
Post by: Marc Sibilia on July 18, 2019, 02:52:22 pm
Here is (I hope) a screen shot of the HF as seen in SMAART.

To me, that looks like a difference in latency between the two processors that is showing up in the phase plot.  You could adjust a delay in the faster processor to eliminate the shifting phase.
Title: Re: Replacing my DSP
Post by: Russell Ault on July 18, 2019, 03:03:55 pm
To me, that looks like a difference in latency between the two processors that is showing up in the phase plot.  You could adjust a delay in the faster processor to eliminate the shifting phase.

Yup, a "stepped" coherence in Smaart is a tell-tale sign your measurement delay isn't set properly (as is, for the most part, the fact that it's set to 0.00).

-Russ
Title: Re: Replacing my DSP
Post by: Rob Spence on July 18, 2019, 03:06:30 pm
Yup, a "stepped" coherence in Smaart is a tell-tale sign your measurement delay isn't set properly (as is, for the most part, the fact that it's set to 0.00).

-Russ
So, you are saying it should be zero?

I didn't check and it might have been from whenever I used it last.
Title: Re: Replacing my DSP
Post by: Russell Ault on July 18, 2019, 06:21:40 pm
So, you are saying it should be zero?

Sorry, no, that was unclear of me. Unless you're measuring cables or analogue gear, 0.00 means you've forgotten to set it/auto-find it.

The measurement delay in Smaart is there to make the measured and reference signals "line up" in time, i.e. it delays the reference signal to compensate for delay in the measurement signal. (When measuring something with a microphone, this delay is often largely caused by distance; when measuring a DSP, this delay is caused by latency.)

When the delay isn't set properly, the two signals don't line up, and Smaart goes a little nuts. Magnitude information may or may not survive this, but the phase trace will go haywire, and your coherence will drop in steps as each subsequent time window is further and further away from where it wants to be.

TL;DR - use the delay finder to find and compensate for your measurement's delay.

-Russ
Title: Re: Replacing my DSP
Post by: Tim McCulloch on July 18, 2019, 09:54:50 pm
To expand a little, Rob, Russ is saying that without applying a delay to the reference signal, it will be "ahead" of the measurement signal by virtue of AD/DA conversion and latency created by the processing of the DR.

Use the delay finder.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 18, 2019, 10:05:36 pm
To expand a little, Rob, Russ is saying that without applying a delay to the reference signal, it will be "ahead" of the measurement signal by virtue of AD/DA conversion and latency created by the processing of the DR.

Use the delay finder.

Ok, will do. Note that both inputs are going through DSP. Reference through the old DSP and measurement through new one.

Title: Re: Replacing my DSP
Post by: Tim McCulloch on July 19, 2019, 02:50:07 am
Ok, will do. Note that both inputs are going through DSP. Reference through the old DSP and measurement through new one.

I suggest you do a loop back test for each DSP, whichever has the greatest delay should be your measurement side when you compare.

You need to save the traces on screen, then manipulate the DUT until the magnitude and phase traces overlay the original DSP traces.  You don't have to go back and forth to BOTH processors in real time.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 20, 2019, 05:42:46 pm
So, today I set up to measure again. I stuck a Y cable  in the Pink line and sent it to a dsp and to the reference input to SMAART. For today I only looked at the HF section and so took the HF output of the dsp to the measurement input.
I did this for each dsp, setting the delay for each. I was surprised that my old one had 8.88ms of delay while the new one was only 2.4ms.

Following is a screen capture of the two measurements.

The purple is the NAV480 and the pink is the Venue360 loaded with the same (as close as allowed) values as the Sabine.

I am not sure I need to tweak anything at this point before I set up the rig (after the heat wave) and do an acoustic measurement. I will look at the LF sections first but I wanted to get some feedback from y'all first.

Title: Re: Replacing my DSP
Post by: David Sturzenbecher on July 20, 2019, 07:35:14 pm
So, today I set up to measure again. I stuck a Y cable  in the Pink line and sent it to a dsp and to the reference input to SMAART. For today I only looked at the HF section and so took the HF output of the dsp to the measurement input.
I did this for each dsp, setting the delay for each. I was surprised that my old one had 8.88ms of delay while the new one was only 2.4ms.

Following is a screen capture of the two measurements.

The purple is the NAV480 and the pink is the Venue360 loaded with the same (as close as allowed) values as the Sabine.

I am not sure I need to tweak anything at this point before I set up the rig (after the heat wave) and do an acoustic measurement. I will look at the LF sections first but I wanted to get some feedback from y'all first.

Rob,
I have measured the transfer function of a lot of DSPs, and i have never seen one produce responses so jagged (that didnít have FIR).  These sure look like acoustical measurements.
Title: Re: Replacing my DSP
Post by: Russell Ault on July 20, 2019, 08:24:04 pm
Rob,
I have measured the transfer function of a lot of DSPs, and i have never seen one produce responses so jagged (that didnít have FIR).  These sure look like acoustical measurements.

I was going to say.

Rob, the approach you're describing (measuring the old DSP on its own, capturing that trace, and then measuring the second on its own while adjusting it to match) is the right approach, but what DSP settings are you using that are producing those traces? It looks like you're using a lot of filters.

Also, did you turn off the coherence trace?

-Russ
Title: Re: Replacing my DSP
Post by: Rob Spence on July 21, 2019, 12:53:13 am
I was going to say.

Rob, the approach you're describing (measuring the old DSP on its own, capturing that trace, and then measuring the second on its own while adjusting it to match) is the right approach, but what DSP settings are you using that are producing those traces? It looks like you're using a lot of filters.

Also, did you turn off the coherence trace?

-Russ

There are 4 filters for each band plus the HP & LP of the crossover.
I realized that I didnít apply any smoothing. Been a while since I did this.

I turned off the coherence trace for the screen shot. I would not expect much coherence given the output is expected to be much different than the input?

Title: Re: Replacing my DSP
Post by: David Sturzenbecher on July 21, 2019, 01:07:23 am
There are 4 filters for each band plus the HP & LP of the crossover.
I realized that I didnít apply any smoothing. Been a while since I did this.

I turned off the coherence trace for the screen shot. I would not expect much coherence given the output is expected to be much different than the input?

If your measurement is purely in the electrical domain, you don't need any smoothing.  Something is wrong with your setup.   It shouldn't be jagged like that at all.  It should look nearly identical to the EQ curve pictures on the screen.
Title: Re: Replacing my DSP
Post by: Russell Ault on July 21, 2019, 01:53:21 am
I turned off the coherence trace for the screen shot. I would not expect much coherence given the output is expected to be much different than the input?

Coherence is a measure of how likey the two signals are to be related, not just how similar they are. When measuring something like an EQ coherence should be 100% for every frequency in the passband (if your delay is set properly), dropping down only when a pass filter has dropped the signal close to the noise level.

There are 4 filters for each band plus the HP & LP of the crossover.

Just so we're clear, is your measurement signal just a cable running directly from the output of the DSP to the input of your USB interface, or is there a speaker and a measurement microphone in your test setup as well?

-Russ
Title: Re: Replacing my DSP
Post by: Rob Spence on July 21, 2019, 12:23:24 pm
Coherence is a measure of how likey the two signals are to be related, not just how similar they are. When measuring something like an EQ coherence should be 100% for every frequency in the passband (if your delay is set properly), dropping down only when a pass filter has dropped the signal close to the noise level.

Just so we're clear, is your measurement signal just a cable running directly from the output of the DSP to the input of your USB interface, or is there a speaker and a measurement microphone in your test setup as well?

-Russ

Thanks by the way to everyone who is helping me with this. I really do appreciate it.

The setup is as follows:

MacBook connected to USB-Pre.
Pink noise from SMAART V7 to the output.
One output of the USB-pre through a Y cable to the dsp & and an input.
The output of the dsp to the other input.

My system sounds amazing with current settings on old DSP. After 10 years I had not needed to make any changes other than to back line delay depending on the venue. I want to make new dsp behave the same.

My first attempt at setting delay got me strange negative numbers (like 500ms+) so I swapped inputs and then got what seemed to be realistic numbers - 8.88ms for the old unit and 2.4ms for the dbx Venue360.

Please ask anything. I took SMAART classes a long time ago and only used it a few times in the meantime. I find the spectrograph useful for determining splay when using multiple speakers.

Anyway, thanks again for helping.


Title: Re: Replacing my DSP
Post by: Russell Ault on July 21, 2019, 12:58:24 pm
MacBook connected to USB-Pre.
Pink noise from SMAART V7 to the output.
One output of the USB-pre through a Y cable to the dsp & and an input.
The output of the dsp to the other input.

Okay, that's definitely the correct setup, but the traces don't look right at all for the filters you're describing. What does the trace look like if you bypass everything in the DSP (including the HPF and LPF)?

-Russ
Title: Re: Replacing my DSP
Post by: Rob Spence on July 21, 2019, 02:13:13 pm
Okay, that's definitely the correct setup, but the traces don't look right at all for the filters you're describing. What does the trace look like if you bypass everything in the DSP (including the HPF and LPF)?

-Russ

Good question. I will try it. At least the basement is cool and I donít need to be outside again today.
Title: Re: Replacing my DSP
Post by: Doug Johnson on July 21, 2019, 03:18:47 pm
Is your delay set right? 
if you are using your Sabine as the reference signal @ 8.88ms and the DBX @ 2.4ms as your measurement.  The Sabine should be a 0 delay and the DBX at 6.48ms delay, i.e. the difference between the two units.  From the screen shot it looks like you have the delay set at 2.4ms but, I may be wrong as I never upgraded from V.6 and am not familiar with v.7.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 21, 2019, 03:43:21 pm
Is your delay set right? 
if you are using your Sabine as the reference signal @ 8.88ms and the DBX @ 2.4ms as your measurement.  The Sabine should be a 0 delay and the DBX at 6.48ms delay, i.e. the difference between the two units.  From the screen shot it looks like you have the delay set at 2.4ms but, I may be wrong as I never upgraded from V.6 and am not familiar with v.7.

I measured each dsp separately. Since I did the dbx last, the delay is shown at 2.4ms.
Title: Re: Replacing my DSP
Post by: David Sturzenbecher on July 21, 2019, 03:49:53 pm
I measured each dsp separately. Since I did the dbx last, the delay is shown at 2.4ms.

I still canít get over why these are so jagged. They should look almost exactly like the pretty pictures shown on the screen. Can you confirm that your tests are completely silent with no pink noise heard at all. I am suspicious that your tests are using your computers internal speakers or something weird.
Title: Re: Replacing my DSP
Post by: Mark Wilkinson on July 21, 2019, 04:41:07 pm
Hey Rob, Ditto David's concerns...something is wrong from the git-go if single processor traces are so jagged..can you do a screen grab of your soundcard's I/O Config....

Also, what output  from the two processors are you trying to compare?  Looks like the HF band so far?
How is your NAV480 set up?  IOW, how many bands is the output split into?  (Will help knowing in offering recommendations on how to compare total processing)

Title: Re: Replacing my DSP
Post by: Mike Caldwell on July 21, 2019, 08:18:59 pm
I was curious today so I fired up my old version of SMARRT on my equally as old lap top and grabbed an extra 360 I have.

The blue trace is full range bandpass and the red is high pass output
with a couple eq points and a low pass filter.

My IO is nothing fancy just a small Allen Heath ZED mixer with USB.
Title: Re: Replacing my DSP
Post by: Russell Ault on July 22, 2019, 12:46:19 am
The blue trace is full range bandpass and the red is high pass output
with a couple eq points and a low pass filter.

That's what I would have expected. Rob, can you run the same test?

-Russ
Title: Re: Replacing my DSP
Post by: Rob Spence on July 22, 2019, 01:11:10 am
Hey Rob, Ditto David's concerns...something is wrong from the git-go if single processor traces are so jagged..can you do a screen grab of your soundcard's I/O Config....

Also, what output  from the two processors are you trying to compare?  Looks like the HF band so far?
How is your NAV480 set up?  IOW, how many bands is the output split into?  (Will help knowing in offering recommendations on how to compare total processing)

Both processors are set up for bi-amp QRX212s and mono subs.
I have another preset for aux subs but till I solve this that doesnít matter.

I feel like a total newby. I should know this stuff. Embarrassed.

Good suggestion on checking my sound card setup.
I admit to not looking at it since I got pink out where I expected it.

Looks like I have time Monday afternoon to hook it all up again.
I will get a screen shot of the config and post it.

I agree I was expecting to see basically the eq curve.

Thanks so much.
Title: Re: Replacing my DSP
Post by: Russell Ault on July 22, 2019, 01:26:06 am
Good suggestion on checking my sound card setup.
I admit to not looking at it since I got pink out where I expected it.

Honestly, given what you're seeing on the screen, I'd take a step back and start by taking your wye-cable from the output and plugging it directly into both inputs. Set the delay at 0 and run a transfer function. If the result isn't flat magnitude and phase with 100% coherence then at least you know the problem exists with your test rig. At that point I'd try using a different interface and also check to make sure there aren't any microphone correction curves being applied.

Let us know what you find out!

-Russ
Title: Re: Replacing my DSP
Post by: Dan Richardson on July 22, 2019, 12:06:19 pm
I measured each dsp separately. Since I did the dbx last, the delay is shown at 2.4ms.

Y an arbitrary source into the inputs of both. Make the faster device your reference, and the other your measurement. Find the delay. Now the coherence will be relevant, and your goal is a flat line.
Title: Re: Replacing my DSP
Post by: Mark Wilkinson on July 22, 2019, 02:47:51 pm
Aah Rob, don't feel that way at all...man, unless you use this stuff regularly it's like forgetting math or a foreign language..at least to me  :)

I think Russ suggested the right starting point:  run the output of your soundcard through a y-cable to both the soundcard reference and measurement inputs.  If that doesn't straightline both magnitude and phase let us know (and try a different soundcard if you have one).

Assuming the soundcard test passes:  unhook the y-cable from the measurement input, and run it to the Sabine's input. Output the Sabine back to the soundcard input.
You should get a fairly smooth mag trace trace that reflects the xover and EQs in place. After you hit delay finder, phase should look pretty smooth too.
Note the delay finder time.  If all this doesn't go well, let us know...

Assuming Sabine went well, unplug it and put the Venue360 in its place.  Make sure you are comparing the same passband that you did for the Sabine.
Same drill, mag should look fairly good with similar shapbe to the Sabine, and phase too after delay finder.



Compare the delay finder times:  add some delay to the Venue360 if it's delay finder time doesn't already exceed the Sabine.
We want the Sabine to be the reference channel since you have been happy with it, and want the Venue360 to replicate it.
Reference channel must have the shorter delay.

Now, run the soundcard's y-cable output to both processors: output the Sabine to the reference input, and the Ven360 to measurement.
Hit delay finder and you should have mag and phase traces that are reasonably close to straight lines. Any deviations from straight represent the difference in the Venue 360 from the Sabine.

Play with the Venue360's settings until you get a straight line.

I thought I'd step it out real basic for any who might be following/considering all this.  Hope it helps..
Title: Re: Replacing my DSP
Post by: Rob Spence on July 22, 2019, 02:55:14 pm
I started over today.
SMAART pink into both inputs. Got expected flat line.

Moved measurement input to NAV LF out with pink in and measured delay.
Got good looking output with flat coherence. Whew.
Did capture. Moved pink and measurement to Venue. Set delay. Got good looking output though, as expected, a little different from the NAV480.
Tweaked filters to make the traces overlap as much as I could.

Repeated for HF.

Will post screen shots soon.

I will try doing both units next. Thanks all. I feel I am making progress finally though sure am puzzled as to what I had screwed up.

Title: Re: Replacing my DSP
Post by: Rob Spence on July 22, 2019, 03:29:53 pm
I started over today.
SMAART pink into both inputs. Got expected flat line.

Moved measurement input to NAV LF out with pink in and measured delay.
Got good looking output with flat coherence. Whew.
Did capture. Moved pink and measurement to Venue. Set delay. Got good looking output though, as expected, a little different from the NAV480.
Tweaked filters to make the traces overlap as much as I could.

Repeated for HF.

Will post screen shots soon.

I will try doing both units next. Thanks all. I feel I am making progress finally though sure am puzzled as to what I had screwed up.

Here are the screen shots. One is LF of Venue compared to NAV. The other is HF.

Title: Re: Replacing my DSP
Post by: Rob Spence on July 22, 2019, 03:34:44 pm
I tried feeding pink to both and comparing the outputs. Delay finder got -6.4.
The display doesn't have very good coherence. Will post.
Title: Re: Replacing my DSP
Post by: Mac Kerr on July 22, 2019, 03:35:51 pm
Here are the screen shots. One is LF of Venue compared to NAV. The other is HF.

Well, that's much better. What was different?

Mac
Title: Re: Replacing my DSP
Post by: Rob Spence on July 22, 2019, 03:45:04 pm
I tried feeding pink to both and comparing the outputs. Delay finder got -6.4.
The display doesn't have very good coherence. Will post.

Here are the shots of NAV & Venue feeding the inputs.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 22, 2019, 03:46:38 pm
Well, that's much better. What was different?

Mac

I must have got some cabling mucked up?

I unplugged everything and started over.
Title: Re: Replacing my DSP
Post by: Chris Grimshaw on July 22, 2019, 05:08:45 pm
Interesting that the HF boost stops abruptly at about 10kHz. Did they not want the top octave..?


The curves look much better now.

Chris
Title: Re: Replacing my DSP
Post by: Mark Wilkinson on July 22, 2019, 05:18:52 pm
I tried feeding pink to both and comparing the outputs. Delay finder got -6.4.
The display doesn't have very good coherence. Will post.

Way to go Rob !
Try adding 10ms or so delay in the Ven360 so that it lags behind the Sabine...then hit delay finder to bring them into time...
Title: Re: Replacing my DSP
Post by: Russell Ault on July 22, 2019, 09:25:08 pm
Here are the screen shots. One is LF of Venue compared to NAV. The other is HF.

Okay, so you've got the magnitude basically spot on, but your phase traces aren't lining up. Did you run the delay finder again after setting the filters on the VENU360? Depending on how the NAV was configured, relative delay between HF and LF might be important for component alignment, so it's important to compare apples to apples.

-Russ
Title: Re: Replacing my DSP
Post by: David Sturzenbecher on July 23, 2019, 07:59:58 am
Interesting that the HF boost stops abruptly at about 10kHz. Did they not want the top octave..?


The curves look much better now.

Chris

This is incredibly common.  Typically the boost needed to maintain flat response to 20k is crazy... so itís best to simply not even try.  You would be surprised the number of boxes that claim to hit 20k, however the DSP curves show otherwise.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 23, 2019, 03:45:12 pm
This is incredibly common.  Typically the boost needed to maintain flat response to 20k is crazy... so itís best to simply not even try.  You would be surprised the number of boxes that claim to hit 20k, however the DSP curves show otherwise.

Looking closely, it is the coherence that dropped at 10k, the magnitude plot continues on toward 16k but got masked by the coherence.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 25, 2019, 08:29:42 pm
Looking closely, it is the coherence that dropped at 10k, the magnitude plot continues on toward 16k but got masked by the coherence.

Spent some more time and I think I am done with this phase. Next I need to set up one sub with one top and use a measurement mic. I was thinking about 10' out from the speakers and the height about midway up the top cabinet?

Here are the screen shots for the HF and LF. The HF looks pretty good to me though I don't understand why the coherence goes crazy at about 10kHz. I could not get the LF to look better at this time but will work on it more when running the actual speakers and amps.

 
Title: Re: Replacing my DSP
Post by: Tim McCulloch on July 25, 2019, 09:28:26 pm
Your delay could be off by a sample or 2, try changing the delay time +/- the smallest increment and see what happens with the phase trace.

That said, it probably doesn't matter.
Title: Re: Replacing my DSP
Post by: David Sturzenbecher on July 25, 2019, 09:39:01 pm
Spent some more time and I think I am done with this phase. Next I need to set up one sub with one top and use a measurement mic. I was thinking about 10' out from the speakers and the height about midway up the top cabinet?

Here are the screen shots for the HF and LF. The HF looks pretty good to me though I don't understand why the coherence goes crazy at about 10kHz. I could not get the LF to look better at this time but will work on it more when running the actual speakers and amps.

Rob what are we looking at here?   These again look like acoustical measurements, but the naming in Smaart says Nav vs Venue, implying that that you are using the output of the Sabin as the reference trace, and the output of the Drive Rack as the measurement.  This would be a completely valid test, yet i would prefer to just overlay traces.

The amount of phase wraps i see on the LF looks excessive no matter if it is an acoustical measurement or electrical

When I copy DSP settings from one device to another....I honestly don't even worry about taking acoustical measurements anymore.   If the transfer functions are the same...It. Is. The. Same. (**ruling out dynamics - limiting - or any other changes in the signal path)
Title: Re: Replacing my DSP
Post by: Dave Garoutte on July 25, 2019, 10:00:11 pm
Be careful of the ground reflection with hard surfaces.
If you can measure on a lawn, better.
Title: Re: Replacing my DSP
Post by: Rob Spence on July 26, 2019, 12:37:45 am
Rob what are we looking at here?   These again look like acoustical measurements, but the naming in Smaart says Nav vs Venue, implying that that you are using the output of the Sabin as the reference trace, and the output of the Drive Rack as the measurement.  This would be a completely valid test, yet i would prefer to just overlay traces.

The amount of phase wraps i see on the LF looks excessive no matter if it is an acoustical measurement or electrical

When I copy DSP settings from one device to another....I honestly don't even worry about taking acoustical measurements anymore.   If the transfer functions are the same...It. Is. The. Same. (**ruling out dynamics - limiting - or any other changes in the signal path)

I posted earlier with overlay traces. I captured the transfer function of the Sabine, one for HF and one for LF , then tweeked the crossover and EQ for each on the driverack till they matched as good as I could.

I was thinking a listening test was in order before my next festival so no surprises and while set up, might as well measure.
Title: Re: Replacing my DSP
Post by: Rob Spence on August 07, 2019, 11:14:23 am
So, yesterday I set up the amp rack and a QRX212 on top of a TH118 in the driveway. I don't have a lawn as my home is on a rocky hillside in the woods. Half the project was cables... first, hooking 50a tails in a panel to my distro, and then a 30a cable out to the amp rack. Part of the test was to verify the power changes I made as well as listen to the rig with new DSP.

In hind sight, I should have also listened with the old DSP as it is still in the rack and only 3 XLRs need moving... Oh well, I may try again next week.

The bottom end seemed weak to me which is why I need to calibrate against the old unit.

A couple of anomalies showed up in measurement. There was a consistent huge dip at 170hZ and a smaller one at around 500hZ. Neither is near a crossover point. I am thinking that the 170hZ dip contributed to my impression of a weak low end. I did test inverting the polarity of the sub but other than the expected reduction of low end, it didn't change anything.

I worried that perhaps there was an issue with the speaker, so I repeated the measurements with another cabinet. The results were close enough to rule out a driver problem. I have each speaker in my inventory labeled with an id so in the event of something sounding wonky at a gig, I can note the unit for a checkup back at the shop.

So, I have 2 screen shots to post. One with just the QRX sitting on the sub and a second with the sub enabled. In each case the confidence line for the HF section looks pretty good. The LF has those anomalies mentioned above.

Comments and/or suggestions?

Thank you all!!


Title: Re: Replacing my DSP
Post by: Chris Grimshaw on August 07, 2019, 11:42:18 am
I'd put £5 on floor bounce.
Change the mic or speaker height, and the frequency will move.

Chris
Title: Re: Replacing my DSP
Post by: Frank Koenig on August 07, 2019, 12:26:33 pm
Another approach to getting a "reference delay" for sub-top alignment is to measure each in the extreme near field. The phase (not magnitude) obtained this way agrees with free field measurements quite well and does not require an anechoic environment. This is what I do in "living room" situations where there are modes galore and no chance of getting a pseudo-anechoic measurement at any frequency, least of all low ones.

See "Low-Frequency Loudspeaker Assessment by Nearfield Sound-Pressure Measurement", D. B. KEELE, JR., JAES APRIL 1974, VOLUME 22, NUMBER 3

On EQing the top octave I agree with David. You choose your battles. I usually look for the last usable peak as things drop off and make that the top frequency for EQ. The correction curve is flat above that. I can't hear anything up there anymore anyway but I do my (measured) best for the youngsters  :P

--Frank
Title: Re: Replacing my DSP
Post by: Jay Barracato on August 09, 2019, 08:06:02 am
I have been using a Sabine Nav 480 for a long time. It has served me very well but I think the time has come to replace it as Sabine is no more and I worry about a failure these days. I will likely keep the Sabine racked as a spare.

I use it with subs and two pair of EV QRX-212s running in bi-amp mode.

I got my original settings for it from EV way back when. I actually sent the unit to an engineer at EV and he derived the settings for me from their reference DSP.

I have two primary configurations I use. A standard stereo crossover with HF, MF and mono sub out. The second one is similar except I use 3 inputs for Aux fed subs.

The new DSP is a dbx DR360.
I found a set of parameters for a DR260 that Evan Kirkendal posted. Does anyone know if DR260 settings will work with a DR360? I know that setting are not always portable due to different DSP implementations.

Alternatively, is there a current contact at EV who might have settings for the DR360? I didnít find anything on the EV website besides their own DSPs.

I suppose I could feed pink noise into a channel of my old DSP and a channel of the new one and use SMAART to make the new one the same as the old. I may do that anyway but starting with something close should make it easier.

Thoughts?

Thanks

I had been running a 4xqrx212 over 2xsrx728 up until last Sept in a 600+ person room with a base model driverack. I had tuned the system with smaart and then tweaked to taste. I don't remember all of my settings but a few significant things I do remember are:

1. High passing subs at 80 and low passing tops at 100 to smooth out the transition

2. Lowering the crossover point of the tops to about 1.1, pulling back the relative level of the hf driver, and using a pretty big shelf at the top end to reduce the hissyness. Yes I was giving up some max volume, but I had what the room needed.

I do remember having a few specific eq band tweaks but the were done in place and we're room specific not box specific.

By the way, I ran a Sabine 4800 for years on my personal system when my main boards were ls9/01v/analog mostly for parametric eq and fill delay with powered boxes. Since changing to m32/x32, the Sabine is basically retired. My one passive system I do the dsp processing in the amp these days.
Title: Re: Replacing my DSP
Post by: David Morison on August 09, 2019, 03:56:04 pm
I had been running a 4xqrx212 over 2xsrx728 up until last Sept in a 600+ person room with a base model driverack. I had tuned the system with smaart and then tweaked to taste. I don't remember all of my settings but a few significant things I do remember are:

1. High passing subs at 80 and low passing tops at 100 to smooth out the transition


Please tell me that was a slip of the mind, and you aren't really using those subs as nothing more than glorified speaker stands for your tops?
Title: Re: Replacing my DSP
Post by: Rob Spence on September 07, 2019, 04:07:05 pm
Ok, old thread but same dsp

I have a question on setting delays on the Venue 360.

Over on the alignment section, I have a small delay on the LF output as per specs. The other outputs are zero.

There are two more areas for delays but they are grayed out.
I want to set a 6ish ms delay for the tops to better align with the subs but want to avoid the LF alignment setting so if I klutz while tuning up the rig in the field, I donít mess up the top box internal alignment.
Also, I would like to add a back line delay as that can vary by venue due to stage depth and mains location.
So, it seems like the 2 grayed out sections are perfect for this but, how do I use them?

I could use output delays on the mixer but I like having all the speaker processing in one place.

I created 2 configurations on the dsp. One as stereo 2 way with mono subs and one as stereo 2 way with aux subs.

I got surprised (though I should not have) that the sub output was 6dB lower on the aux sub configuration as it isnít getting signal from the mixing of 2 inputs.

So, where do all yíall put the extra gain needed? On the aux out of the desk? On the input mixer in the dsp?  Or...?


Thanks.
Title: Re: Replacing my DSP
Post by: Tim McCulloch on September 07, 2019, 06:05:47 pm
Ok, old thread but same dsp

I have a question on setting delays on the Venue 360.

Over on the alignment section, I have a small delay on the LF output as per specs. The other outputs are zero.

There are two more areas for delays but they are grayed out.
I want to set a 6ish ms delay for the tops to better align with the subs but want to avoid the LF alignment setting so if I klutz while tuning up the rig in the field, I donít mess up the top box internal alignment.
Also, I would like to add a back line delay as that can vary by venue due to stage depth and mains location.
So, it seems like the 2 grayed out sections are perfect for this but, how do I use them?

I could use output delays on the mixer but I like having all the speaker processing in one place.

I created 2 configurations on the dsp. One as stereo 2 way with mono subs and one as stereo 2 way with aux subs.

I got surprised (though I should not have) that the sub output was 6dB lower on the aux sub configuration as it isnít getting signal from the mixing of 2 inputs.

So, where do all yíall put the extra gain needed? On the aux out of the desk? On the input mixer in the dsp?  Or...?


Thanks.

It's about the limited processing blocks.  What I did for your stereo 2 way with mono subs... recalled preset 8.  Enter config mode and on the Input side, replaced the GEQs with backline delay.  On the Output side, replace the compressors (not the limiters) on A and B with Fill Delay.

For subs on aux levels I'd put the +6dB on the crossover output if matching up to the mono subs level is important.  Since most sub on aux is "turn it up until you like it" it may not matter as much.
Title: Re: Replacing my DSP
Post by: Rob Spence on September 07, 2019, 07:49:03 pm
It's about the limited processing blocks.  What I did for your stereo 2 way with mono subs... recalled preset 8.  Enter config mode and on the Input side, replaced the GEQs with backline delay.  On the Output side, replace the compressors (not the limiters) on A and B with Fill Delay.

For subs on aux levels I'd put the +6dB on the crossover output if matching up to the mono subs level is important.  Since most sub on aux is "turn it up until you like it" it may not matter as much.

Thanks Tim
Title: Re: Replacing my DSP
Post by: Matt Greiner on December 02, 2019, 02:39:09 pm
Rob,
If there is flexibility, I would really recommend a processor from EV that does FIRs for those boxes. Something like the EV DX46.  In my experience it does take them to the next level. Or look at the TGX amps with processing inside.

I just recently acquired several pairs of the EV Qrx212's as well, and was looking into proper DSP for them.  I can't find the DX46 anywhere on the EV website, other than a press release from 2010.  Does anyone know if they are discontinued?  Or does anyone have one laying around they may be willing to part with?  If not, I may end up going the same route as Rob with a dbx venu360.
Title: Re: Replacing my DSP
Post by: David Sturzenbecher on December 02, 2019, 04:42:15 pm
I just recently acquired several pairs of the EV Qrx212's as well, and was looking into proper DSP for them.  I can't find the DX46 anywhere on the EV website, other than a press release from 2010.  Does anyone know if they are discontinued?  Or does anyone have one laying around they may be willing to part with?  If not, I may end up going the same route as Rob with a dbx venu360.

The DX46 is still showing on my dealer pricing sheet. List cost is $1933.   
Title: Re: Replacing my DSP
Post by: Kevin Maxwell on December 02, 2019, 06:00:43 pm
I just recently acquired several pairs of the EV Qrx212's as well, and was looking into proper DSP for them.  I can't find the DX46 anywhere on the EV website, other than a press release from 2010.  Does anyone know if they are discontinued?  Or does anyone have one laying around they may be willing to part with?  If not, I may end up going the same route as Rob with a dbx venu360.

I picked up the DX46 that I have used and really like how it works with Biamping the QRX212 speakers with the EV supplied FIR filters.
Title: Re: Replacing my DSP
Post by: Matt Greiner on December 02, 2019, 06:03:38 pm
The DX46 is still showing on my dealer pricing sheet. List cost is $1933.

I apologize, I should have been more clear in my post.  You are correct, they do have a few units left in their stock.

I guess I was more interested in knowing if they truly were discontinued, or if them being absent from the website was an oversight.  Or maybe even a new, updated product to take it's place.  Perhaps I'm wrong for feeling this way, but I'm not excited about purchasing a product that is (potentially) no longer manufactured.
Title: Re: Replacing my DSP
Post by: Matt Greiner on December 02, 2019, 06:06:49 pm
I picked up the DX46 that I have used and really like how it works with Biamping the QRX212 speakers with the EV supplied FIR filters.

Not to beat a dead horse, but were you using a driverack (or other DSP) before? Or just running them full range?
Title: Re: Replacing my DSP
Post by: Kevin Maxwell on December 02, 2019, 06:22:48 pm
Not to beat a dead horse, but were you using a driverack (or other DSP) before? Or just running them full range?

I was using a DBX 4800 Drive rack. BTW I am not a fan of the dbx venu360.
Title: Re: Replacing my DSP
Post by: Tim McCulloch on December 02, 2019, 08:42:41 pm
I was using a DBX 4800 Drive rack. BTW I am not a fan of the dbx venu360.

I was about to order a Venu360 to allow remote muting and level control for a front fill speaker system that is not otherwise controllable by Audio Architect.  Not doing loudspeaker component alignments or rocket surgery.  I might use it to HP the fills, too.  I played with the control software in demo mode and it seems possible to do what I need; is there something I'm missing about the device itself?  Is there another HiQNet device I should consider?
Title: Re: Replacing my DSP
Post by: Mike Pyle on December 02, 2019, 10:09:51 pm
I was about to order a Venu360 to allow remote muting and level control for a front fill speaker system that is not otherwise controllable by Audio Architect.  Not doing loudspeaker component alignments or rocket surgery.  I might use it to HP the fills, too.  I played with the control software in demo mode and it seems possible to do what I need; is there something I'm missing about the device itself?  Is there another HiQNet device I should consider?

If it would be any advantage to you I have one of the Venu360-D Dante versions on the shelf.
Title: Re: Replacing my DSP
Post by: Tim McCulloch on December 02, 2019, 10:47:44 pm
If it would be any advantage to you I have one of the Venu360-D Dante versions on the shelf.

I was a big dummy.  Until you mentioned Dante I just figured the RJ45 on the back spoke HiQNet.  It does not. :(  I will pursue other avenues.
Title: Re: Replacing my DSP
Post by: David Sturzenbecher on December 02, 2019, 10:54:11 pm
I was about to order a Venu360 to allow remote muting and level control for a front fill speaker system that is not otherwise controllable by Audio Architect.  Not doing loudspeaker component alignments or rocket surgery.  I might use it to HP the fills, too.  I played with the control software in demo mode and it seems possible to do what I need; is there something I'm missing about the device itself?  Is there another HiQNet device I should consider?

BLU-50's are cheap new, All the other BLUs are cheap on Ebay. If you need it to be a DSP, and have XLRs, you might just be limited to 4800s, which should really be cheap at this point as they are dinosaurs. If they aren't self powered front fills, there are only like 20 different HiQnet amps to choose from.
Title: Re: Replacing my DSP
Post by: Kevin Maxwell on December 02, 2019, 11:32:05 pm
I was a big dummy.  Until you mentioned Dante I just figured the RJ45 on the back spoke HiQNet.  It does not. :(  I will pursue other avenues.

It has been a while since I played with one but I think it either needed a crossover Cat cable or it is only the USB that works to control it. It wasn't as logical as all of the other DBX DSPs that I have used and that is almost everyone that they make.
Title: Re: Replacing my DSP
Post by: Tim McCulloch on December 03, 2019, 01:23:17 pm
BLU-50's are cheap new, All the other BLUs are cheap on Ebay. If you need it to be a DSP, and have XLRs, you might just be limited to 4800s, which should really be cheap at this point as they are dinosaurs. If they aren't self powered front fills, there are only like 20 different HiQnet amps to choose from.

They are powered boxes and not from the Harman family.  Was actually looking a Blu-100, it would nicely handle a couple of things, like being my "mixer switcher" plus give me inputs for house music, MC and VOG.