Preferred Amp for RL-p 15

**Owen Bartley** · **10-19-06, 09:10 AM**

I'm at that point of indecision where I keep flip-flopping back and forth, and each day a different option seems the best. What I'm trying to figure out is what is the best way to amplify a killer sub?

Now my current sub uses a plate amp, but it doesn't need a lot of power and wasn't a long cable run. The main benefit I see to using most plate amps is the variable phase, as I found this hugely valuable when I was setting up my sub.

On the other hand, there are a lot of more conventional amps that put out serious power for very little money (especially comparatively). On the down side, you may have fan noise to deal with, and I don't think I know of one with a variable phase adjustment.

Is there a specific amp that you guys like for this application, or will I eventually just have to sort out my priorities?

**Darren** · **10-19-06, 09:12 AM**

Behringer EP2500... I've never used phase other than 180 degrees out and all you have to do is switch the leads to achieve that. Fan noise is a non issue, for $10 you can swap the stock fan out with a quiet fan that you can't hear beyond 2 feet away.

**Jerm357** · **10-19-06, 02:59 PM**

Another great option for todays power hungry drivers is the Buttkicker amp. No fan, lots of power, rca input and great price. The only down side is there is only one channel.

http://www.amazon.com/Buttkicker-BKA...027218?ie=UTF8

**Nick77** · **10-19-06, 05:56 PM**

Quote:

Owen Bartley wrote:

I'm at that point of indecision where I keep flip-flopping back and forth, and each day a different option seems the best. What I'm trying to figure out is what is the best way to amplify a killer sub?

Now my current sub uses a plate amp, but it doesn't need a lot of power and wasn't a long cable run. The main benefit I see to using most plate amps is the variable phase, as I found this hugely valuable when I was setting up my sub.

On the other hand, there are a lot of more conventional amps that put out serious power for very little money (especially comparatively). On the down side, you may have fan noise to deal with, and I don't think I know of one with a variable phase adjustment.

Is there a specific amp that you guys like for this application, or will I eventually just have to sort out my priorities?

I also use the EP2500 and feel the fan is a non issue although I have heard many make a big deal of it.

**Otto** · **10-19-06, 10:33 PM**

Quote:

Nick77 wrote:

I also use the EP2500 and feel the fan is a non issue although I have heard many make a big deal of it.

Oh, man, are you sure you're in the same room with that EP2500?!?!?! As soon as I think I'm done tweaking my IB, that thing is getting buried in the basement!

**dynamowhum** · **10-19-06, 11:22 PM**

I have the EP1500 right behind my couch in an open rack and I don't really hear it. Course I have 50 year old ears and 25 or so of those in construction and refinery work. YMMV

**Darren** · **10-20-06, 08:58 AM**

Quote:

Otto wrote:

Oh, man, are you sure you're in the same room with that EP2500?!?!?! As soon as I think I'm done tweaking my IB, that thing is getting buried in the basement!

For a mere $10 you can make the EP2500 silent...its so simple a 5 year old could do it.

**SteveCallas** · **10-20-06, 09:48 AM**

Quote:

For a mere $10 you can make the EP2500 silent...its so simple a 5 year old could do it.

Of all the EP2500 mods I've read about, the best you can hope for is to bring fan noise down to ~65db at 1" from the front faceplate. That's still very loud. The Buttkicker would work very well for sealed, maybe a bit much for ported. A bridged mono Carvin HD900 would work very well for ported, with stock fan noise being ~53-55db at 1" from the front faceplate. With a resistor mod, you can bring that down even more.

Both of those recomendations are assuming you are building one sub. If you are building two, then I would go for the EP2500 because of it's cost advantage.

**Darren** · **10-20-06, 09:54 AM**

Quote:

SteveCallas wrote:

Of all the EP2500 mods I've read about, the best you can hope for is to bring fan noise down to ~65db at 1" from the front faceplate. That's still very loud. The Buttkicker would work very well for sealed, maybe a bit much for ported. A bridged mono Carvin HD900 would work very well for ported, with stock fan noise being ~53-55db at 1" from the front faceplate. With a resistor mod, you can bring that down even more.

Both of those recomendations are assuming you are building one sub. If you are building two, then I would go for the EP2500 because of it's cost advantage.

I'm not sure where you are hearing that nonsense about not being able to quiet the EP2500 below a certain db level

. I have one, put a quiet fan in... 21db at 1 foot. Quiet enough? It only cost $10.

I bought the following fan for a replacement:
Panaflo FBA08A24L1A, 24V, 80x25.5, 21dB
Digikey P/N P9739-ND, $8.25

All you have to do is buy the appropraite Panaflow quiet fan and swap it out. See how with my thread here: http://ibsubwoofers.proboards51.com/...ead=1145627913 or a resistor mod here: http://www.cwitt.com/epfanmodification/index.html

**SteveCallas** · **10-20-06, 12:43 PM**

Hmm, can you do me a favor and try at 1"? 21db at 1'......ambient room noise is typically in the 30db range at least.

**Darren** · **10-20-06, 12:45 PM**

I can give it a whirl tonight... I didn't take "actual" measurements.. I was going off the specs. I can't hear the fan beyond 2 feet. I can barely hear it when I place my ear near it, that's all the test I really need. Did you want me to take actual measurements tonight? I doubt there will be anything beyond ambient room noise.

**brucek** · **10-20-06, 03:04 PM**

Quote:

Hmm, can you do me a favor and try at 1"? 21db at 1'

How would you propose to measure 21dBSPL.... the lowest an RS meter reads is 50dBSPL.

brucek

**SteveCallas** · **10-20-06, 04:31 PM**

Quote:

Did you want me to take actual measurements tonight? I doubt there will be anything beyond ambient room noise.

You don't have to, but if you believe it's significantly less than 65db at 1" slow C weighting, you might want to check for your own sake. I've already followed several such mods with this amp - you may get slightly less than 65db, but nobody's gotten into the 50's, not even with fan swaps and resistor mods. It measures in at ~72db at 1" before any mods. While 65db at 1" is "dead silent" for some, it's pretty annoying for others.

Quote:

How would you propose to measure 21dBSPL.... the lowest an RS meter reads is 50dBSPL

Yep, I figured perhaps he was using a pro mic, but then even if that were the case, his ambient room noise would be at least 30db.

**Darren** · **10-20-06, 04:39 PM**

Well, I'll tell you this, I've never heard a fan quieter than the one I have for this amp. You cannot possibly hear it at more than 2 feet away so I can't imagine it could possibly be an issue for anyone.

**Darren** · **10-20-06, 06:04 PM**

Ok, here's the scoop.

Measured with my Radio Shack SPL meter C weighting:

Ambient room noise at 2 feet: wouldn't register
Amp fan turned on at 2 feet: wouldn't register
Amp fan turned on at 1" from opening: 54db

So, if you listen to your music sitting 1" from your amp you might be in trouble

otherwise you won't hear it.

**dynamowhum** · **10-21-06, 06:16 AM**

No offense but I was just wondering why the interest at 1" and how this relates to real world listening? Cheers.

**Darren** · **10-21-06, 08:46 AM**

I was responding to SteveCallas' request of measurement at 1", I'm not sure why he is interested in that measurement either as it really has no value when testing for listening in real world circumstances as you suggested. Maybe he wants it for comparison, not sure.

**Josuah** · **10-21-06, 04:11 PM**

You can extrapolate SPL over distance based on a fixed distance. So comparing two fans both measured at 1" away makes sense. And I don't know about you guys, but my projector fan is supposed to be rated at ~22dB and that's already loud for me, and higher than the ambient room noise. I'll have to take a 1" measurement too; maybe it's not 22dB.

**dynamowhum** · **10-21-06, 04:58 PM**

Ah yes I remember the days of golden hearing, alas those are days of yore for me. I did hear my EP 1500 this morning when I came into the room and somebody had forgotten to shut it off. It was the only piece of equipment running with no load on it. I guess because I work in a high noise inviorment with ear plugs in that I just have tuned that noise level out.
By the way what is that extrapolation formula Josuah? Cheers.

**Josuah** · **10-21-06, 05:26 PM**

So I measured my projector at 58dB@1" from the fan exhaust. The projector is rated at 25dB, which is probably at one meter. I believe the formula is -6dB/doubling of distance. So that'd be 52dB@2", and just about 25dB@1m. I sit about 1m below the projector. It was too annoying and so I built a hushbox that probably decreases the SPL by about 6dB. So I'm guessing it's around 20dB at my seat. It's okay, but I still wish it'd be quieter.

**Owen Bartley** · **10-21-06, 05:35 PM**

Really, that's all the hushbox cut out? I thought they were supposed to make a projector almost silent. Another HT myth exposed I guess. Heh.

**SteveCallas** · **10-21-06, 05:43 PM**

Quote:

Amp fan turned on at 1" from opening: 54db

Interesting, you're 10db lower than others who have done fan and resistor mods on that amp. Good job.

Quote:

No offense but I was just wondering why the interest at 1" and how this relates to real world listening?

It's a good way to compare fan noise from one amp to another. If you start measuring from further away, other things can be contributing to ambient noise - at 1", you're getting a better read of the just the amp. If we measured at our seats, we all sit different distances away, some have carpeted rooms while other don't, some have plaster walls while others have drywall, etc. etc. Just trying to eliminate variables.

Quote:

I believe the formula is -6dB/doubling of distance

In an anechoic environment, yes. In a typical room, I think it's much less than that. I measured my sub to put out almost identical output levels from 6' and 11' in my room with the same master volume level.

**Josuah** · **10-21-06, 06:24 PM**

It's a DIY hushbox, and still has to remain open to the room because I don't have any other exhaust system. A full-fledged hushbox would do much better.

I'm surprised you got equal SPL at 6' and 11' away from your sub. I can easily hear the drop off as I walk away from my sub.

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