Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Tim McCulloch]

Thanks for that.  So I changed the input sensitivity on the amp from 15 to 21 db and from 15 to 21db on the drive rack and still was about the same performance.  I still had to crank the mixer more then on the qsc to get as much volume out of the subs.  But what is surprising to me is that the tone seems much deeper and more natural to me through the QSC.  The crown is heavier, noisier (both with the annoying fan and through the speaker), and the tone is not as deep.  I'm getting more mid range than deep bass out of the crown.  And for the tops I still prefer the cleaner tone of the QSC.

The ITech series has 2 "maximum input level" selections, but those are not to be confused with changing the input sensitivity.  I don't remember if input sensitivity can be changed from the front panel or requires a computer running System Architect or Audio Architect and connection to the amplifier.

There are lots of things inside an ITech that can affect gain - it's a sophisticated product - and I strongly urge you to read the manual and call Crown if you have questions.  They have folks that can help you (ask for Kevin Gring, who posts here occasionally).

We do not own (and I do not typically use) MRX or PRX series speakers but based on the comments of users on these forums it sounds to me like you have a button, knob, or some "feature" used incorrectly or inconsistently.  Rather than make more side-by-side comparisons I suggest starting over with the powered boxes without external processing and assiduously avoiding ANY "wizards" or automatic stuff.

And I would NOT substitute drivers or transducers simply because some random DJ (even if he's a great DJ) thinks he's a loudspeaker designer.

[Steve Oldridge]

I changed the input sensitivity on the amp from 15 to 21 db and from 15 to 21db on the drive rack and still was about the same performance.  I still had to crank the mixer more then on the qsc to get as much volume out of the subs. 

Alex,
have you ever gained staged your system? If you have, run the mixer, etc. at unity should give you max output across your system.
What did upping the input sensitivity gain provide you? 
If doing so did not drive ur amps into clipping then I would guess ur system has not been gain staged correctly - or at all.

I have a BL right now that loves the auto-rta/EQ. It adds artifacts into the system that ALWAYS have to be adjusted/corrected - and as mentioned above - are only valid at the position of the RTA mic. I totally dislike that tool. He and I have been round and round about the benefits - or lack of - that feature. I won't even mention the inline BBE he likes. I no longer raise the issue with him, because he believes the GC "pro's" over me. <shrug>

But - I'd take Tim's advice

starting over with the powered boxes without external processing and assiduously avoiding ANY "wizards" or automatic stuff.

And I would NOT substitute drivers or transducers simply because some random DJ (even if he's a great DJ) thinks he's a loudspeaker designer.

[Alex Magor]

 I suggest starting over with the powered boxes without external processing and assiduously avoiding ANY "wizards" or automatic stuff.

Yes I did run straight from the board to the powered boxes without any drive rack in between.  It is just a very different sound than the passive boxes with QSC amps that I am used to.  It is a much more colored sound.

[Ray Aberle]

Starting with the I-Tech, are you using absolutely clean (empty) pre-sets with no processing or crossovers applied? Never hurts to ensure you have the latest firmware installed, of course. I know you've already been fussing in it, but if there's something else set/configured that you've not noticed, that could explain your issue with feeling like it's not doing the same as your PLX3602 did. GRANTED that the actual difference (in real world SPL difference between the related numbers) is not huge, given the max power of the QSC of 1250w/4ohms and 775w/8ohms is less then the "Guaranteed Minimum Output" of the I-Tech of 1,250w/8ohms and 2,000w/4ohms, I'd still think you should see something more out of the I-Tech.

-Ray

[Stephen Kirby]

I'm still confused over what the OP actually has vs. is looking at buying.  A lot of scattershot questions and replies.

If he has 518s then 718s will get a bit louder.  If he has 718s then he either needs to go for more boxes, dual 18s or a tapped horn type thing to get noticeably more "punch" or "kick".

It would be good to get a better description of what Alex considers a "processed" sound.  Does this mean a more forward midrange?  Harsher?  I kind of like the CD horn on the MRX as it doesn't have that classic icepick in the forehead JBL sound although the driver is kind of weak and can't be pushed very hard compared to SRX level stuff.  If he's used to that more scooped DJ sound, then a flat system will sound forward and artificial to him.  I'm surprised EV's haven't come up as they traditionally have a warmer voicing, although they are getting my JBLish as you go up the modern lines.
As someone who's long been adverse to "that" sound, I've very happy with my DSRs which might be another option although I don't think they have subs to keep up with the latest JBLs and a mixed system isn't quite as plug and play convenient.  Which in a wedding band is a big asset.  Event coordinators expect you to be able to get in and out quickly and take up minimal footprint.  Siamese cables to a powered system is quick and clean and limits the amount of "ugly wires" that wedding planners abhor. 

[Alex Magor]

Again current setup = dbx venu 360.  Jbl mrx515 x2, Jbl mrx518 x2.  Powered by 2x QSC plx3602's.  If I could make an analogy of the coloration I hear it is similar to the difference between my active genelec speakers vs passive yamaha ns-10's.  I think it may just be the acoustic aspect of empty passive cabinets that resonate more openly and freely. 

[Alex Magor]

Also it sounds like on the Jbl powered speakers like there is some type of eq in line whereas the passive box and amp sounds closer to wire + gain.

[Alex Magor]

I just got a chance to check out an in store demo of the Rcf evox 12 and I was much more impressed over the Jbl powered speakers.  These seem smaller, lighter, more powerful and less colored.  I will likely be getting a set in my studio to put up against the passive Jbl setup.  The powered jbls i returned already to the store

[Luke Geis]

The PRX probably has a more linear sound to it to be honest. A speaker that is relatively flat ( lets use the word linear ) has a sound to it, and that sound is usually said to be up front and apparent. This is due to the lack of the DJ smile and the more balanced amount of highs and lows in comparison. It doesn't have the Fletcher Munson curve built in. In theory the powered speaker will be as close to AMP/WIRE/SPEAKER as you can get. The lack of cable between the amp and the speaker will help make the speaker follow the input even better ( less cable length improves the damping factor ). So in all actuality the PRX in comparison to the MRX should be sonically superior. Now whether you like that sound or not is the question? Obviously you don't like it.

The PRX will and does have an EQ preset in it, along with limiting, excursion and thermal protections. So when you have the thing pushed to the limiters, then you may notice what I call a processed sound. To me a processed sound is one that has been highly compressed and has a very linear sonic character. Imagine your favorite CD from the mid 90's to early 2000's, that is processed. A speaker that is linear is typically easier to get a balanced mix with at the cost of not sounding as sweet and warm ( no DJ smile type sound ). The sweet and warm sound is now up to the engineer to get. I will detail why a linear speaker is more of a goal:

1. When you have a linear speaker system, canned ( commercial ) music sounds more like it was intended to ( no DJ smile please ).

2. When you mix live music through a linear system you can easier make it sound like the canned music and utilize a little less energy doing it. That DJ smile type sound makes the bass seem really heavy with canned music. So when you try and replicate it, your really using a lot of energy to do so. The balance of the instruments is easier to acquire because the PA is not colored as much. When the PA is not as colored, natural sound is easier to accomplish.

Lets define linear: Linear is not necessarily flat. It doesn't mean that the PA is a perfectly horizontal line from 20-20. It more simply means that the PA is devoid of large dips and humps that color the sound. You can have a little more emphasis on the lows and reduce the emphasis on the highs if you like, but in essence a linear system is like a see-saw. The fulcrum is near the middle and ideally you shoot to have it level and balanced, but you can add weight to one side or the other if desired. To polish things off there is also usually a 10db per octave roll off of highs from 2khz - 20 khz ( the last octave ). Now that doesn't mean that you should go out and shoot to get the flattest PA possible. A linear PA doesn't always sound very good. It is a taste thing. The primary objective is to mitigate the large humps and dips and to have a nice balance from one end to the other. There just happens to be a little more emphasis on the low end usually.

Now I am not saying that the PRX is perfectly linear, only that it is likely to more linear than the MRX. Most PA speakers have a little hump around the 80hz area to get the oomph many like. Some have a little cut around 500hz to give it that DJ smile and many also have a little boost in the high end to give it some sparkle and again, that DJ smile.

As mentioned you will have to dig deeper into the I-Tech and be sure of the settings. The two amps you have produce nearly identical power and should be nearly identical in output and sonic character. The extra noise you are hearing from the I-Tech is due to the input setting you used ( 15db or 21 db ) in combination with the actual input sensitivity.

[Rob Spence]

I just got a chance to check out an in store demo of the Rcf evox 12 and I was much more impressed over the Jbl powered speakers.  These seem smaller, lighter, more powerful and less colored.  I will likely be getting a set in my studio to put up against the passive Jbl setup.  The powered jbls i returned already to the store

My $.02
Stop buying things until you have a plan.
Check here before buying or you must have too much money because you are wasting it.

Don't replace drivers in a cabinet unless you know how to read the specs and what they mean. Not just watts and frequency response of a raw driver. Once you put it in a cabinet, lots changes.

For me, I don't mix QSC amps and Crown amps.

For sub duty, if I wanted Crown, I would be looking at IT6000 or bigger.
I had a 6000 and didn't like it on my subs. I sold it and got a big QSC for them.


Sent from my iPad using Tapatalk HD

[ProSoundWeb Community]