Print

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

[Benjamin Goulart]

I got a couple charity gigs coming up and I don't want to bring the lab subs.  I've determined that the weak link in my heavily-modified (glue, nails, screws, new caps) single, smaller sub for little or charity gigs is having constant problems with the driver.  It's one of these, but the amp and the box are pretty much o.k. on it now.  I'm only running it at a 2 on the back volume knob to prevent distortion of the driver, and I know I can get to between 5 and 7 before the amp clips with a hot pro nominal signal music source with the DSP filters I'm using right now (no EQ, mind you).  So I need a recommendation for a driver with better power handling and better bass tone for this box and built-in amp.

http://www.seismicaudiospeakers.com/18-Inch-Powered-Subwoofer-Cabinet/p/EnforcerII_PW?utm_source=googlepla&utm_medium=CSE&utm_campaign=CA&utm_content=productAdEnforcerII_PW&CAWELAID=1912445504&CAGPSPN=pla&catargetid=330005100000036626&cadevice=c&gclid=CKHEzfH23cMCFQaQaQod-DIAHA#product-description-text

•MODEL: Enforcer II PW - 18 Inch Powered Subwoofer Cabinet
•POWER RATING: 1200 Watts RMS
•WOOFER: 18" Subwoofer - 120 oz Magnet and 4" Voice Coil
•LPF (Low Pass Filter): 45Hz - 800 Hz
•SENSITIVITY: 101 dB
•CONNECTORS: Line Input - 1/4" and XLR Combo Jacks; Line Output - XLR Male
•NOMINAL IMPEDANCE: 8 Ohms
•DIMENSIONS: 28" x 22" x 22" - 98 lbs per Cabinet
•ENCLOSURE: 5/8" Birch Plywood Construction

[Scott Holtzman]

I got a couple charity gigs coming up and I don't want to bring the lab subs.  I've determined that the weak link in my heavily-modified (glue, nails, screws, new caps) single, smaller sub for little or charity gigs is having constant problems with the driver.  It's one of these, but the amp and the box are pretty much o.k. on it now.  I'm only running it at a 2 on the back volume knob to prevent distortion of the driver, and I know I can get to between 5 and 7 before the amp clips with a hot pro nominal signal music source with the DSP filters I'm using right now (no EQ, mind you).  So I need a recommendation for a driver with better power handling and better bass tone for this box and built-in amp.

http://www.seismicaudiospeakers.com/18-Inch-Powered-Subwoofer-Cabinet/p/EnforcerII_PW?utm_source=googlepla&utm_medium=CSE&utm_campaign=CA&utm_content=productAdEnforcerII_PW&CAWELAID=1912445504&CAGPSPN=pla&catargetid=330005100000036626&cadevice=c&gclid=CKHEzfH23cMCFQaQaQod-DIAHA#product-description-text

•MODEL: Enforcer II PW - 18 Inch Powered Subwoofer Cabinet
•POWER RATING: 1200 Watts RMS
•WOOFER: 18" Subwoofer - 120 oz Magnet and 4" Voice Coil
•LPF (Low Pass Filter): 45Hz - 800 Hz
•SENSITIVITY: 101 dB
•CONNECTORS: Line Input - 1/4" and XLR Combo Jacks; Line Output - XLR Male
•NOMINAL IMPEDANCE: 8 Ohms
•DIMENSIONS: 28" x 22" x 22" - 98 lbs per Cabinet
•ENCLOSURE: 5/8" Birch Plywood Construction

I doubt that amp can do 300 watts.  The position of the control is immaterial.

I think you may spend all that money on a driver (what's your budget, decent 18" sub drivers are at least $300).  The cabinet dimensions are just one factor.  You need to measure the vent and grab one of the decent shareware speaker designer software packages.

Plug in all of the dimensions and the Thiel Small parameters for different drivers and look at the output plot.  It's not going to be linear so you will also have an idea what kind of EQ you need to flatten the box out.  You will need a 3 or 4 band parametric to get it really tuned.

[Benjamin Goulart]

I doubt that amp can do 300 watts.  The position of the control is immaterial.

I think you may spend all that money on a driver (what's your budget, decent 18" sub drivers are at least $300).  The cabinet dimensions are just one factor.  You need to measure the vent and grab one of the decent shareware speaker designer software packages.

Plug in all of the dimensions and the Thiel Small parameters for different drivers and look at the output plot.  It's not going to be linear so you will also have an idea what kind of EQ you need to flatten the box out.  You will need a 3 or 4 band parametric to get it really tuned.

I'm mentioning the position of the control because I'm sending a hot pro nominal signal from a DSP and I can turn it up to around 6 out of 20 marked notches before the amp clips, but I can hear the sub going crazy at only a 2 on the volume control on the back.  So the amp can push the driver far beyond what the driver can handle.

The amp looks very substantial, and I believe a similar woofer on their site is listed as 500W RMS.  Doesn't it make sense that the amp has been overdriving and damaging the woofer over time if I've been running it just under clipping previously?  Shouldn't I try to get a woofer that can handle around a 1000W RMS or more to be safe?

The vent on the bottom front measures 5"x19".

[Scott Holtzman]

I'm mentioning the position of the control because I'm sending a hot pro nominal signal from a DSP and I can turn it up to around 6 out of 20 marked notches before the amp clips, but I can hear the sub going crazy at only a 2 on the volume control on the back.  So the amp can push the driver far beyond what the driver can handle.

The amp looks very substantial, and I believe a similar woofer on their site is listed as 500W RMS.  Doesn't it make sense that the amp has been overdriving and damaging the woofer over time if I've been running it just under clipping previously?  Shouldn't I try to get a woofer that can handle around a 1000W RMS or more to be safe?

The vent on the bottom front measures 5"x19".

That's a very inexpensive speaker and the power is not speced over a give frequency range or with a distortion spec.  You certainly could run a 50hz sine wave into it and measure the voltage before it clips and figure out exactly what it is putting out.

[Ivan Beaver]

I'm mentioning the position of the control because I'm sending a hot pro nominal signal from a DSP and I can turn it up to around 6 out of 20 marked notches before the amp clips, but I can hear the sub going crazy at only a 2 on the volume control on the back.  So the amp can push the driver far beyond what the driver can handle.

The amp looks very substantial, and I believe a similar woofer on their site is listed as 500W RMS.  Doesn't it make sense that the amp has been overdriving and damaging the woofer over time if I've been running it just under clipping previously?  Shouldn't I try to get a woofer that can handle around a 1000W RMS or more to be safe?

The vent on the bottom front measures 5"x19".

As Scott said-the postion of the control means ALMOST NOTHING.

It is not an indicator.  The actual level depends on the ENTIRE chain and what levels (NOT position of knobs) are being run.

What is a "hot pro signal"?

0dB?  +10dB?  +28dB?

What you are dealing with is cheap gear that very often has GREATLY inflated spec numbers.

What does "looks very substantial" mean?  As compared to what?  What are the power supply caps rated at-that is a good start to "guessing" at the output capacity.

What is wrong with taking your lab subs?

if you have them-then why not use them-instead of trying to spend more money on a garbage project.

You really need to look at more pro gear and that will give you an idea of why you may be having issues with the "cheap stuff".

[Scott Holtzman]

As Scott said-the postion of the control means ALMOST NOTHING.

It is not an indicator.  The actual level depends on the ENTIRE chain and what levels (NOT position of knobs) are being run.

What is a "hot pro signal"?

0dB?  +10dB?  +28dB?

What you are dealing with is cheap gear that very often has GREATLY inflated spec numbers.

What does "looks very substantial" mean?  As compared to what?  What are the power supply caps rated at-that is a good start to "guessing" at the output capacity.

What is wrong with taking your lab subs?

if you have them-then why not use them-instead of trying to spend more money on a garbage project.

You really need to look at more pro gear and that will give you an idea of why you may be having issues with the "cheap stuff".

I think he means the amp is quite large in size, it's like 8x10 if I recall and heavy.  Large extrusion.  Since it's not class D probably larger than his reference of current gear.

Doesn't mean a thing as to the quality of the power supply, the output transistors, as Ivan said the capacitors for energy storage. 

I just passed on the "high pro signal" as it has no meaning. 

You can't polish a turd and a diamond in a cheap setting doesn't show it's luster.  As you mentioned you already had to reglue the enclosure, why toss good money after bad? 

The only way in the world to make it work is to properly determine the output power of the amplifier.  Take measurements of the ports on the enclosure (that includes the folded portion volume and size) and feed them into a speaker design program.  Then you can put in the TS parameters of different drivers and see what they do in that enclosure.  No shortcuts. 

[Benjamin Goulart]

The caps and toroid on the amp are huge.  I had to do a lot of modding on that too for reducing vibration in the form of adding silicone mats under the toroid to reduce vibrations, tighten stuff up, seal some air leak holes, etc.

The part of the cabinet that needed modification was the bottom of the main top chamber that is also the top of the vent section.  Most of the staples had missed. That and the amp section rattling were probably the reasons I got it so cheap. 

I can't tell you if the driver early on was working fine because the rest of the sub was making so much noise.  I put some nice screws in there, as well as a bunch of shoe glue to seal the edge.  It did wonders.  So the box itself is not a problem anymore, assuming I can get a driver that will sound o.k. with it and assuming the amp is working right.

The first DSP in the digital chain (mid/high EQs, width & output for labsubs) is being fed near its maximum 0dBFS.  The limiter is turned off, so compression isn't occuring.  I only ever let it peak at around -1.5dBFS on the inputs by accident sometimes.  The DSP's max input is +22dBu.  The second DSP in the digital chain is doing the high-pass & low-pass filters and the delays.  I think last night when I was running it I also had the summed out to the SA sub at -6dB to compensate for the added volume.  I'm mentioning the volume control on the back of the sub more because of the comparison aspect.  The sub's trim knob setting for this driver to run undistorted is usually 1/2 to 1/3 what the amp can push (assuming the volume knob rotation that close to the two settings is fairly linear) prior to clipping.  So either the amp can put out more than the driver is spec'd at, or the driver is damaged, or both, right?

It does produce ok bass at low volumes.  Unless it's in a corner or the whole system is turned down & the sub is boosted, you can't hear it over the tops.  Outside up against a house, it's barely audible even pushed to just under clipping.  If the amp can put out more than the sub can handle, though, then those outdoor events may have screwed it up.

I assume if I test the amp, then what I'll be seeing is volts with, what, no resistance?

I'm also wondering, though, if I would just be better off buying some lighter subs than either the labsubs or the SA.  If I can find a pair of good condition, low-weight dual-driver subs, then that's essentially 4 working drivers and two more boxes.  Some of these good, high power sub drivers are over $500.

Maybe I should also buy one of the cheap SA replacement woofers in addition to some super-lite subs.  I have a spare amp nu3000DSP I still haven't opened.  Are you guys more concerned about the quality of the amp than the drivers in the SA stuff, or both?  The driver has always appeared to be well built, is very heavy, and does have a huge ferrite magnet on there.  It definitely does not move the way youtube videos of it show, though.  I or the prior owner may have just over-driven it.

I'll make sure to measure the cabinent more in detail once I get it open this weekend, and also check the caps for numbers.  Here's a pic of the big cap board prior to replacing it.

[Scott Holtzman]

The caps and toroid on the amp are huge.  I had to do a lot of modding on that too for reducing vibration in the form of adding silicone mats under the toroid to reduce vibrations, tighten stuff up, seal some air leak holes, etc.

The part of the cabinet that needed modification was the bottom of the main top chamber that is also the top of the vent section.  Most of the staples had missed. That and the amp section rattling were probably the reasons I got it so cheap. 

I can't tell you if the driver early on was working fine because the rest of the sub was making so much noise.  I put some nice screws in there, as well as a bunch of shoe glue to seal the edge.  It did wonders.  So the box itself is not a problem anymore, assuming I can get a driver that will sound o.k. with it and assuming the amp is working right.

The first DSP in the digital chain (mid/high EQs, width & output for labsubs) is being fed near its maximum 0dBFS.  The limiter is turned off, so compression isn't occuring.  I only ever let it peak at around -1.5dBFS on the inputs by accident sometimes.  The DSP's max input is +22dBu.  The second DSP in the digital chain is doing the high-pass & low-pass filters and the delays.  I think last night when I was running it I also had the summed out to the SA sub at -6dB to compensate for the added volume.  I'm mentioning the volume control on the back of the sub more because of the comparison aspect.  The sub's trim knob setting for this driver to run undistorted is usually 1/2 to 1/3 what the amp can push (assuming the volume knob rotation that close to the two settings is fairly linear) prior to clipping.  So either the amp can put out more than the driver is spec'd at, or the driver is damaged, or both, right?

It does produce ok bass at low volumes.  Unless it's in a corner or the whole system is turned down & the sub is boosted, you can't hear it over the tops.  Outside up against a house, it's barely audible even pushed to just under clipping.  If the amp can put out more than the sub can handle, though, then those outdoor events may have screwed it up.

I assume if I test the amp, then what I'll be seeing is volts with, what, no resistance?

I'm also wondering, though, if I would just be better off buying some lighter subs than either the labsubs or the SA.  If I can find a pair of good condition, low-weight dual-driver subs, then that's essentially 4 working drivers and two more boxes.  Some of these good, high power sub drivers are over $500.

Maybe I should also buy one of the cheap SA replacement woofers in addition to some super-lite subs.  I have a spare amp nu3000DSP I still haven't opened.  Are you guys more concerned about the quality of the amp than the drivers in the SA stuff, or both?  The driver has always appeared to be well built, is very heavy, and does have a huge ferrite magnet on there.  It definitely does not move the way youtube videos of it show, though.  I or the prior owner may have just over-driven it.

I'll make sure to measure the cabinent more in detail once I get it open this weekend, and also check the caps for numbers.  Here's a pic of the big cap board prior to replacing it.

Is that cap leaking?  Hard to tell from the pic.

What side of the country are you on?  I have a stamped steel 18" woofer, 800w continuous, 1600 peak.  It is a Behringer replacement driver from their B1800 pro cabinets.  A far more expensive unpowered box than you powered and it is still considered "low end" and a one note wonder.   

Send me a PM if that will help you out.

To measure output I would guess the speaker is closest to it's impedance spec at the 2x the resonant frequency so figure about 60hz.  Voltage^2 / Impedance so 50^2/8 = 312.5 so if you get 50v you are 3db away from 600 watts.  The cabinet should also be withing 6db of the max output at that point.

If it can do that, nothing is broken.



BTW the reason I have the pile of Behringer woofers is the same thinking as you have, so I learned from mistakes.  I got a couple of the Behringer cabinets, happen to have a B&C woofer laying around.  I put it in and it wasn't bad.  A little chuffing and the box was larger than it was supposed to be so it was a little loose.  I ended up reworking the ports, adding a board at the top and bottom between the factory plastic (makes them much more sturdy) and re-nailing and gluing the box plus a brace with big screws. 

As you mentioned a good woofer is not cheap.  I got a deal on more of the B&C's at 300 and came upon 4 more of the cabinets.  It's not a bad looking cabinet (it's not carpeted) but quite a bit of work.  It was probably still cheaper than building the cabinets.

Anyway, just wanted you to know I have been down the road you are going.

[Benjamin Goulart]

Is that cap leaking?  Hard to tell from the pic.

What side of the country are you on?  I have a stamped steel 18" woofer, 800w continuous, 1600 peak.  It is a Behringer replacement driver from their B1800 pro cabinets.  A far more expensive unpowered box than you powered and it is still considered "low end" and a one note wonder.   

Anyway you can have it for $25.00 plus shipping.

To measure output I would guess the speaker is closest to it's impedance spec at the 2x the reasonant frequency so figure about 60hz.  Voltage X Voltage / Impedance so 2(50)/8 = 312.5 so if you get 50v you are 3db away from 600 watts.  The cabinet should also be withing 6db of the max output at that point.

If it can do that, nothing is broken.

Send me a PF if you want the woofer and I will get it packed up.  I have a couple of other things to ship this weekend that were supposed to go out all ready!

BTW the reason I have the pile of Behringer woofers is the same thinking as you have, so I learned from mistakes.  I got a couple of the Behringer cabinets, happen to have a B&C woofer laying around.  I put it in and it wasn't bad.  A little chuffing and the box was larger than it was supposed to be so it was a little loose.  I ended up reworking the ports, adding a board at the top and bottom between the factory plastic (makes them much more sturdy) and re-nailing and gluing the box plus a brace with big screws. 

As you mentioned a good woofer is not cheap.  I got a deal on more of the B&C's at 300 and came upon 4 more of the cabinets.  It's not a bad looking cabinet (it's not carpeted) but quite a bit of work.  It was probably still cheaper than building the cabinets.

Anyway, just wanted you to know I have been down the road you are going.

Yeah, one or two of the caps were leaking in that photo, hence the reason I replaced the cap board.

I tested a little mini Roland and got 5V prior to clipping on the voltmeter.  On SA amp it's reading 0.09, up from 0.02 when it's off.  That's either me doing something wrong or an indication there's an issue with the amp.  I used 50hz signals.  I'm going to try running the Roland into the woofer and see if it get's louder.

The driver actually appears to be fine.  It moves without noise, had a good "drum" tone when I tap the cone, and though quite stiff in the surround, seems to be moving symmetrically.  Another mod I forgot: I found the spider adhesive to be brittle, though it hadn't come off yet, so I re-glued it extremely well.  That's never coming loose again.  It might tear off the cone, but it's never coming off the magnet.

---

I just tested with the nu3000dsp amp in bridge mode, and it can get very, very loud.  The amp plate starts to rattle again, as I don't think it's ever been run this hard before.  Not too bad.  It seems capable of keeping up with the tops now and it's not even in a corner.  I guess I need to find an appropriate speakon plate for it or get the amp repaired.  Guess I could use a piece of plywood and put a little plate in the middle.  Right now I've just got the grill off, a wire through the front, and up around the vent to the woofer.

Give me few days to test it some more before I decide what to do about that Behringer woofer.  Thanks for the offer, but I only had 5 minutes to test the speaker before it's quiet bedtime.

[Scott Holtzman]

Yeah, one or two of the caps were leaking in that photo, hence the reason I replaced the cap board.

I tested a little mini Roland and got 5V prior to clipping on the voltmeter.  On SA amp it's reading 0.09, up from 0.02 when it's off.  That's either me doing something wrong or an indication there's an issue with the amp.  I used 50hz signals.  I'm going to try running the Roland into the woofer and see if it get's louder.

The driver actually appears to be fine.  It moves without noise, had a good "drum" tone when I tap the cone, and though quite stiff in the surround, seems to be moving symmetrically.  Another mod I forgot: I found the spider adhesive to be brittle, though it hadn't come off yet, so I re-glued it extremely well.  That's never coming loose again.  It might tear off the cone, but it's never coming off the magnet.

---

I just tested with the nu3000dsp amp in bridge mode, and it can get very, very loud.  The amp plate starts to rattle again, as I don't think it's ever been run this hard before.  Not too bad.  It seems capable of keeping up with the tops now and it's not even in a corner.  I guess I need to find an appropriate speakon plate for it or get the amp repaired.  Guess I could use a piece of plywood and put a little plate in the middle.  Right now I've just got the grill off, a wire through the front, and up around the vent to the woofer.

Give me few days to test it some more before I decide what to do about that Behringer woofer.  Thanks for the offer, but I only had 5 minutes to test the speaker before it's quiet bedtime.

Don't worry about the woofer, I have a pile of them.  I am glad you are pointed in the right direction.  I would not bother with the amp.  Just make a cover plate with a pair of speakons and call it a day.

[David Morison]

  Voltage X Voltage / Impedance so 2(50)/8 = 312.5 so if you get 50v you are 3db away from 600 watts. 

Do Americans use different notation that the rest of us?
Over here 2(50) would denote 2 x 50 = 100, rather than 50^2 (or simply 50²) for 2500, as you've evidently used in your actual calculation.
Cheers,
David.

[Scott Holtzman]

Do Americans use different notation that the rest of us?
Over here 2(50) would denote 2 x 50 = 100, rather than 50^2 (or simply 50²) for 2500, as you've evidently used in your actual calculation.
Cheers,
David.

No it's squared, I was in a hurry when I typed that.  I will fix it.  Thanks for the catch.

Also, in retrospect I don't think you are allowed to offer stuff for sale like that.  My intention was to help the guy out of a jam but it could look like a commercial solicitation so I took that out too.

[ProSoundWeb Community]