# Which plate amplifier



## Lee Batchelor (Jul 6, 2014)

Hi team,

I have decided to buy a subwoofer amplifier for my newly completed Lab 12 sub. It can be a plate or external amplifier. It will be receiving its signal from the LFE out of my Denon receiver (model AVR 2308 CI). I need about 500 watts and the ability to adjust high pass frequencies from 20 to 80 Hz. I was thinking of the Dayton plate amps, but I really respect everyones' opinions on this forum, so please feel free to kick in some ideas .

Money is not a huge concern. I'll only deal with a reputable source that has no problem shipping to Canada and honoring warranties in a trouble-free manner. Many thanks!

- Lee


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## willis7469 (Jan 31, 2014)

Hi lee, going off your mention of 500 watts only, I would use a BASH 500. Not knocking Dayton, but I have used bash as have some oem's as well as SVS for quite awhile before using the sledge amps. You might find more versatility with an outboard pro amp, but for a simple 500, bash amps are hard to beat. X/O is from 50-150.


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## Lee Batchelor (Jul 6, 2014)

Thanks for chiming in, Willis.

I saw that amp on the PE website. It has no high pass filter, which is something most Eminence designs recommend for preventing cone over-excursion. Gazoink advised me that I don't need an amp with a high-pass filter because it can be accomplished from my Denon receiver, however, I've never seen such an adjustment in my Denon. Maybe it's there and I've never noticed it.

Any other ideas or suggestion? Thanks again !

- Lee


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## rkeman (Jan 24, 2014)

The BASH 300 and 500 are good amplifiers and will work well with the Eminence Lab 12 in a vented configuration. The high pass filter is recommended by Eminence to prevent bottoming of the driver when high level signals containing information below the tuning frequency are present. Most home listeners will never encounter this situation except when playing a certain movies containing significant infrasonic effects (e.g. War of the Worlds from 2005) and warped records. The recommendation from Eminence is really aimed at customers in the professional sound community.

The other amplifiers worth considering are the Yung plate amplifiers, Dayton SA230 and SA1000 component amplifiers, HTD ICE-based component amplifiers and the SVS STA-800. The latter is a powerful amplifier with an adjustable parametric equalizer, configurable crossover, and low high pass filter. It may be worth constructing a separate enclosure if a plate amplifier is the choice to minimize the chance of vibration and allow amplifiers to be swapped out more easily.


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## Lee Batchelor (Jul 6, 2014)

Thanks for chiming in. I'm really interested in the Dayton SA1000. It would drive both my musical instrument sub (with the Eminence Kappalite 3015LF driver) and my Lab 12 (separately). Questions:

1- Would it "see" the incoming signal from my Denon receiver's LFE channel the same as how my Paradigm Servo 15 does? That is, is the sensitivity a better match than my ART power amp? (I got my ART amp to work but not as well as the Yorkville powered mixer I started with. The Yorkville mixer boosts the incoming signal by 32 dB.)

2- Does the parametric EQ feature act as a high-pass filter so I can protect my drivers from microphone pops and rumble? I have seen and heard my Lab 12 bottom out (exceed Xmax) from a David Foster CD with a bit of mic pop and not overly large power levels!

Many thanks.

- Lee


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## rkeman (Jan 24, 2014)

Lee Batchelor said:


> Thanks for chiming in. I'm really interested in the Dayton SA1000. It would drive both my musical instrument sub (with the Eminence Kappalite 3015LF driver) and my Lab 12 (separately). Questions:
> 
> 1- Would it "see" the incoming signal from my Denon receiver's LFE channel the same as how my Paradigm Servo 15 does? That is, is the sensitivity a better match than my ART power amp? (I got my ART amp to work but not as well as the Yorkville powered mixer I started with. The Yorkville mixer boosts the incoming signal by 32 dB.)
> 
> ...


1) The Dayton SA1000 would act similarly to the Paradigm subwoofer in terms of input characteristics and gain. Professional amplifiers tend to have a significantly lower input sensitivity than designs intended for domestic use.

2) The SA1000 has both variable low pass and fixed high pass filters as described on the Parts Express website:

Subsonic filter: -3 dB @ 18 Hz, Q=0.8 • Bass boost: +3 dB @ 25 Hz, Q=1.4 • High pass output: -3 dB @ 80 Hz, 12 dB/octave • Low pass adjustment: 30-200 Hz • Phase adjustment: 0°–180° • Parametric EQ frequency: 18–80 Hz • Bandwidth: 0.1–1.0 Q • Level: -14.5 dB to +6 dB •

The parametric equalizer could be tailored as an additional high pass filter, but that really shouldn't be required in most instances.

Do remember that none of these amplifiers will be suitable for continuous duty at rated output. A typical duty cycle would be in the 30% range. More demanding applications are better filled by high power professional amplifiers with forced-air cooling sytems and more elaborate output sections and overload protection.


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## ajinfla (May 10, 2009)

Hi Lee,

Have you considered a DSP amp like a Behringer inuke or a MiniDSP?
Each would allow for both hi-pass filtering and parametric EQ, the Behringer could actually be used for both subs simultaneously, with independent filtering per channel.
If you prefer analog simplicity, a Yamaha P2500 would do (sweepable hi-pass), though you would have to use external parametric EQ, like a Behringer FBQ1000.

cheers,


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## Lee Batchelor (Jul 6, 2014)

Thanks rkeman,

Now I have enough information to completely confuse me . I can design a pretty good speaker but, I'm so used to driving it with a 1970s amplifier with On/Off, Bass, Treble, and Loudness controls. To this day, I'm still mystified by the absolutely pathetic manual Denon sent with their receiver. As a technical writer, believe me when I tell you, Denon dropped the ball on their audience analysis.

Having said that, I'm getting as many opinions as there are members on this forum; with very little consistency. For that, I blame myself, so please let me start all over again and tell you what I need. My subwoofer amplifier must do the following two tasks:


Drive a home theatre system from my Denon receiver. This is for my Lab 12 subwoofer.

Drive a musical instrument sub for my Yamaha arranger keyboard. This is for my Kappalite 3015LF driver. It must pick up the low end from the F3 of my Bose Compacts (F3=65 Hz). This is *not* a rock band sub. It is used mainly for low volume theatre (200 capacity) and senior residents' picnics. I know a plate amplifier would do the trick.
My big worry is cone excursion protection. Bass notes below 30 Hz are not that readable to my ears. Home theatre rumbles such as explosions do drop below that. So far, I have driven both systems successfully with a Yorkville Audiopro 508 powered mixer (250 watts RMS) and an ART crossover with a dedicated subwoofer out channel and 30 Hz high pass filter. The only reason I want to eliminate the Yorkville mixer is because it's too heavy!! Toward that end, I invested in an ART SLA-2 power amp. This is a very good product, but I have yet to get it blend well with my Denon receiver; likely due to the complexity and my own misunderstanding of all the bloatware contained within said receiver. I assume the ART amp will act well with the monitor outs of my Soundcraft mixer and drive my Kappalite sub very well. 

I recalibrated my Denon with the ART amp attached and finally got it working. Problem: if I don't use the ART crossover and its nice volume control and 30 Hz high pass filter, my Lab 12 cone exceeds Xmax from something as simple as microphone pop. I can turn the amp down, but then the bass is anemic. 

I brought the Lab 12 sub, Yorkville mixer, and ART crossover to a friend's house, and hooked it up to the Headphone jack of his 1970s Barney Oliver amplifier. (Perhaps some remember that name--a truly superior amp for its day!) His living room is 34 feet long by 14 feet wide. We just about broke glass, and no bass notes were missing. So my Lab 12 box is right. My big issue is combining the Denon receiver and ART amp. I know I don't need the ART crossover because the Denon receiver has crossover funtionality, but I need that high pass filter. 

Hopefully, I've explained my dilemma. Comments most welcome, and thanks for letting me bend your ears .


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## Lee Batchelor (Jul 6, 2014)

Hi Aj...

Thanks for chiming in. I was writing my response at the same time you were .

There seems to mixed reviews with the Behringer product. I'll take a look at the others too. Many thanks!

- Lee


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## Lee Batchelor (Jul 6, 2014)

I did a bit of homework. Have I got this right?

The Dayton SPA1000 has a high pass filter *and *parametric EQ. I think I'm in error when I say the parametric EQ can be used as a high pass filter. It is used more for cleaning up room issues at know frequencies, right? The over-excursion I'm seeing with my Lab 12, is likely within the range where the Dayton high pass (subsonic) filter works, right? I did forget to mention that my Lab 12 is in a relatively large box = 3.8 cu.ft. making it somewhat more prone to over-excursion from subsonics. 

Just thought I'd add this information to the post. I think the Dayton SPA1000 would be suitable for both of my subs, and especially in the Lab 12, the over-excursion would be eliminated. What say you? Thanks.

- Lee


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## Lee Batchelor (Jul 6, 2014)

I've done more homework.

The parametric EQ *can *be used to prevent subsonic rumble, although, it's not the best choice. According to the Parts Express website:


The SA1000 has a subsonic filter: -3 dB @ 18 Hz, Q=0.8. The 10 Hz to 32 Hz range is suppressed 3 dB
The SPA1000: no subsonic filter mentioned
I'm aiming toward the SPA1000. If so, I can use its parametric EQ as a subsonic filter. Using a Q calculator, I can select 18 Hz, Q=1. This filters frequencies from 11 Hz to 30 Hz. The region from 25 Hz to 30 Hz would not be missing but merely turned down 3 dB so the Lab 12 cone doesn't jump to far. Opinions? Thanks.

- Lee


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## Lee Batchelor (Jul 6, 2014)

More information. I can use a 20 Hz inline subsonic filter from Harrison Labs. The Eminence design calls for a 20 Hz subsonic filter, and I can see why. I have seen my Lab 12 driver just about jump out of the box, onto the floor with that horrible cracking sound, and I'm not driving it beyond it's rated power--at least not with a 250 watt Yorkville mixer.

If I buy the Dayton SPA1000 and place the filter between my Denon and Dayton, the over-excursion is gone while maintaining the 20 to 30 Hz range intact. The Dayton low pass filtering is bypassed, allowing the Denon to control the crossover frequencies. I can still use the Dayton parametric EQ to make up for room losses.

Opinions? Thanks.

- Lee


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## ajinfla (May 10, 2009)

Lee Batchelor said:


> The SA1000 has a subsonic filter: -3 dB @ 18 Hz, Q=0.8. _The 10 Hz to 32 Hz range is suppressed 3 dB_
> - Lee


Hi Lee, not sure how you are getting that 2nd part.
You could email PE, but it appears the SPA and SA have the same subsonic filtering below 18hz (Q 0.8), rendering the FMOD as a cascaded filter that might be overkill. If you feel a single band of EQ is sufficient, then the SPA should work for you.
Almost all plate amps will have a subsonic filter, usually <20hz to protect the drivers from over-excursion.
Then there is DSP, like the ones I mentioned, which are infinitely more flexible.

cheers


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## Lee Batchelor (Jul 6, 2014)

Hi AJ,

Thanks for chiming in. I got those specs right off the PE website. I find it strange that they mention the SA1000 has a subsonic filter, but they don't explicitly say that the SLA1000 has one. All the better if it does.

I measured my Lab 12 with a Sure Beta 58 (I know, not the best but close), and came up with the following non-calibrated curve. The dB response is just how loud I turned up my amp, so please don't take it as the actual subwoofer ability.

As you can see, I need a bump up from about 25 Hz to 60 Hz. I'm hoping to achieve that with the SPA1000 and prevent excursion below 20 Hz. Is that the right amp for that?

Many thanks.

- Lee


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## ajinfla (May 10, 2009)

Lee Batchelor said:


> Hi AJ,
> Thanks for chiming in. I got those specs right off the PE website. I find it strange that they mention the SA1000 has a subsonic filter, but they don't explicitly say that the SLA1000 has one. All the better if it does.
> - Lee


If you scroll down to MattP's comment (he works for PE), you'll see the subsonic filter mentioned for the SLA.



Lee Batchelor said:


> A high-output vocal microphone, the BETA 58A® features a shaped frequency response ideal for close-up vocals.


That's a problem:









Do you have an AVR? Most come with a calibration mic. If you do, that will give you much better LF measurements. Just plug into the mic input on your laptop or pc running TruRTA.

cheers


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## Lee Batchelor (Jul 6, 2014)

Hi AJ,

Holy socks! I never thought about that. I do have a calibration mic for my Denon. I shall re-run the measurement and post it. 

Your graph is most revealing. I measured at 3 feet thinking of the 1 watt, 1 meter idea. No wonder I'm shy from 60 Hz down to 25 Hz. In reality, my Lab 12 is probably linear in response. 

Thanks, AJ!

- Lee


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## Lee Batchelor (Jul 6, 2014)

AJ...I tried using my Audyssey mic with the True RTA program, and no go. It must be calibrated way out of spec for the True RTA program. 

For want of a different mic, do you think my Beta 58 would work at closer range? I also own one of the good old fashion analog Radio Shack SPL meters . Maybe all this digital stuff is...well, just that...stuffy! All my SPL meter needs is a battery and a pair of reading glasses (for me!).

- Lee


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## ajinfla (May 10, 2009)

Lee Batchelor said:


> AJ...I tried using my Audyssey mic with the True RTA program, and no go. It must be calibrated way out of spec for the True RTA program.


Are you using a Windows pc?


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## Lee Batchelor (Jul 6, 2014)

Hi AJ. I use Windows 7 Pro. I attached the AVR mic to my Steinberg CI-1 interface, but it didn't work for this exercise so I re-invoked the PC sound card--Realtek I believe. It was a no go either. I did all the setup stuff listed specifically for a Windows 7 PC in the TrueRTA help file.

Instead, I did a manual reading with my Radio Shack SPL meter and got the results shown below. These values are relative to one another, not measurements of true sensitivity. As you can see, the trend is pretty close to my Shure Beta 58 measurements. Perhaps this is close enough for me to attempt a parametric adjustment. 

By the way, I ordered the SPA1000 today. Hopefully, it will do the trick.


- Lee


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## ajinfla (May 10, 2009)

That's better Lee, but the RS meter is still pretty crude. The AVR mic direct to mic input on your pc as an external mic should work. Did you open the Windows mixer and set the microphone as default?


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## Lee Batchelor (Jul 6, 2014)

Hi AJ,

Yep, did that. Those instructions are very well documented in the TrueRTA help file. They even provide screen shots for Windows 7 and Vista. I went directly into the Realtek sound card with the ⅛ inch plug. I tried using an ⅛ inch to ¼ inch adapter in my Steinberg interface and figured it was the wrong adapter or something, but no go. I Googled the problem and others have tried using Audyssey mics to no avail. 

I'm open to other ideas. Many thanks.

- Lee


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## ajinfla (May 10, 2009)

Hmmm, that makes no sense. An "Audyssey" mic is functionally no different from other calibration mics, other than within the software. It should work, as this gentleman found: http://www.diymobileaudio.com/forum/786945-post18.html. It should work for basic measurements. Forget the calibration part, not needed for LF which is what we are interested in. It's been eons since I set up mine. Is you mic level maxed out in the advanced properties?
I'm pretty sure it's something with your settings, not the mic. Ah well, we gave it a shot.

cheers


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## Lee Batchelor (Jul 6, 2014)

Hi AJ,

I certainly wouldn't rule out pilot error. I've only used the True RTA program a wee bit and find it fairly confusing; and I did buy the 1/24 octave resolution version. It was obviously written by a brilliant person who thinks I'm as brilliant (not true). I agree--a mic is a mic. The only difference is purpose. There should be something there. I did get a squiggly line at first, which resided at about -110 dB if that's possible. My guess is I'm not using the program correctly. And since the designer saw fit to address ONLY an expert audience, the rest of us are left out in the cold. Now you've given me reason to set it up again and give her another whirl. I'll do that and report back.

On a positive note, thanks for hanging in there through this whole thread. I hope to return the favor some day .

- Lee


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## Lee Batchelor (Jul 6, 2014)

Hi again, AJ.

I see the Shure Beta 58 only responds to 50 Hz. My friend has two microphones I can try:

Neumann TLM 103 - frequency response 20 Hz to 20 kHz
Rode NT2-A - frequency response 20 Hz to 20 kHz
What do you think? I know the Rode is a huge seller in Australia and of course, Neumann is simply one of the best. I'm picking them up later today.

- Lee


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## Lee Batchelor (Jul 6, 2014)

Hi AJ,

I know I'm way off topic now, but this will be my last post in this thread. I measured my Lab 12 with the Neumann and Rode microphones respectively. Here are the plots. The levels are relative not absolute. There are no filters or crossovers used either. Thanks for all the help--everyone!

- Lee


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## ajinfla (May 10, 2009)

Lee, Google "Images" search is your friend:
Neumann









Rode









Neither is a measurement mic like you Audyssey. The Rode in Omni mode without HPF might work.
You need to reduce the SPL scale on your graphs by at least half, make upper level around 80-90db to make them readable.
Keep trying to adjust your settings for the Audyssey mic to work.

cheers


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## Lee Batchelor (Jul 6, 2014)

Nuts...now I'm back to square one. Does the Audyssey mic need phantom power? I've also read that it uses special software hardcoded into the Denon AVR, and hence, won't work outside the AVR. I'm out of options. Any ideas on how to get the thing working would be much appreciated. Thanks, AJ.

- Lee


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## Lee Batchelor (Jul 6, 2014)

I've been connecting the Audyssey mic directly to my Steinberg sound interface with a 1/8 to 1/4 inch adapter. Do I need to run it into my Soundcraft mixer first, and then to the Steinberg interface? In other words, does it need pre-amplification?

- Lee


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## Lee Batchelor (Jul 6, 2014)

Hi AJ,

I got the Denon mic working!! It is channeled through my Realtek sound card and there is no calibration file available, however, here is what I got for my Kappalite 3015 LF sub reading--no filters or crossover. I took your advice and adjusted the resolution.

Also, if the moderator is seeing this, I know we're way off the original topic. If he or she wishes to move these posts to a more appropriate area, that's fine. Please post the link if this happens. Many thanks!

- Lee


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## Lee Batchelor (Jul 6, 2014)

Here's the Lab 12 with the home theater mic.


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## DevonD (Apr 27, 2009)

To throw another option at you...

http://www.minidsp.com/products/plate-amplifiers/pwr-dsp1

Very nice plate amp with one of the best built in DSP programs out there. This one has a lot more power than you were asking for but they have other options as well. Or you could wire multiple subs to it. If I were going with a plate amp this would be the top of my list.


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## Lee Batchelor (Jul 6, 2014)

Thanks for chiming in Devon. I shall take a look!

- Lee


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## ajinfla (May 10, 2009)

Lee Batchelor said:


> Hi AJ,
> 
> I got the Denon mic working!! It is channeled through my Realtek sound card and there is no calibration file available


Hi Lee, great. I knew it should work if plugged directly into pc soundcard as I had suggested, just a matter of settings. Calibration is not mandatory for what we are looking at. For HF, it would be.
Now you need to reset your scales, maybe 10db bottom -110db top for level, make the upper frequency limit 500hz, use 1/12th resolution. Should make the graphs a bit more readable. Good job!:T

cheers


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## Lee Batchelor (Jul 6, 2014)

I can't thank you enough, AJ. You (and the others) have been a great resource on this project! 

I'm just waiting for my new Dayton amplifier. Can't wait to take the system for a test drive. So far, I've driven the Lab 12 with one of two amplifiers but in both cases, with a 30 Hz HP filter--too high. I can hear the low notes, but can't "feel" them, which the Lab 12 reproduces beautifully.

More updates to follow when the amp arrives. Perhaps I'll re-sweep the Lab 12 while driven by the Dayton amp. Then we'll be back on topic  !!

- Lee


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