# Thoughts on Pro Amp for Big Garage Speakers



## chad1376 (Dec 27, 2012)

In my ongoing quest to have the most obnoxious garage stereo in the world, I've decided I need more power. I built some line arrays a few years ago with PE buyouts. 16~5" woofers + 32~2" paper cone tweeters per side. It's solid down to 50 hz or so. Right now it's bi-amped using a miniDSP, Adcom GFA 545 II for the woofers and an old 100 WPC reciever for the tweeters. I love the Adcom, but it doesn't have enought "juice" to really bring the speakers up to thier full potential.





I keep eyballing the Behringer NU3000 iNUKE 3000 Watt Power Amplifier 248-6704 which claims 1500wpc into a 2-ohm load. The woofers are wired into 2~4 ohm circuits per side, so I can easily configure my woofers for either an 8-ohm or 2-ohm load.

So, knowing nothing about "cheap" pro-sound stuff, what should I expect? Specs on this stuff is always a bit ambiguous. I'm guessing 3000 watts is an optimistic peak power at some horrid level distortion, but I assume it should be pretty clean at power levels far beyond Adcoms's 100 WPC?

Also, will a 2-ohm load be rough on this amp? Again, it's pretty inexpensive, but I'd like it to last more than an hour.

FWIW, the Adcom would be swapped to tweeter duty, which would be a little upgrade for the upper octives.


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## chad (Jun 30, 2005)

Most pro sound companies are offing the older heavy amps that make mondo power for lighter PWM amplifiers... the used market is literally littered with great amps that someone was not stupid enough to include the word nuke in the model name.

Search crown/crest/QSC


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## IBcivic (Jan 6, 2009)

Nice workmanship :thumbsup:

When I first saw your "garage speakers", this clip came to mind....

Randy Quaid lawn mower scene - YouTube


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## chad1376 (Dec 27, 2012)

I don't get it. My neighbor's lawn mower has never bothered me one bit.

Actually, I live in a neighborhood with large lots, and have several vacant lots around my house, so a little outside music every now and then isn't an issue.

I might look around a bit for some quality used stuff. I guess the trick is knowing how many times the original owner's half drunk "helpers" dropped the rack after a gig.


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## chad (Jun 30, 2005)

chad1376 said:


> I don't get it. My neighbor's lawn mower has never bothered me one bit.
> 
> Actually, I live in a neighborhood with large lots, and have several vacant lots around my house, so a little outside music every now and then isn't an issue.
> 
> I might look around a bit for some quality used stuff. I guess the trick is knowing how many times the original owner's half drunk "helpers" dropped the rack after a gig.


The rack ears generally tell the tale 

In reality if you buy from a reputable sound company or from an install the chances of "Drunk Steve and the Meth-Heads" band owning it before you are pretty slim.
My carver that drives my sub shows some wear but ****, it was out with Clair Brothers for eons, the rest of the stuff looks pretty new, actually bought he processor and mains amp from a guy here 

****ty cell phone pic


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## chad1376 (Dec 27, 2012)

Cool setup. Is that a garage system, or a closeted HT system?

I'm not too worried about aesthetics, as long as whatever I get is solid and reliable. Just thinkin', since my woofers are wired in two banks of 4-ohm each, with seperate terminals, It might work well to get two smaller 4-ohm capable amps. I guess it's time to start trolling eBay, Craigslist and the like.

I'm also working up the nerve to use my garage attic space for some big IB subs. I hate the thought of cutting big holes in the ceiling though.


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## chad (Jun 30, 2005)

Shop/garage My workshop is directly behind my garage closed off with two steel doors, the garage has some in-walls, the shop is set to kill/mastering.

I like the dual 4 ohm idea, 2 ohm is just OK if you don't plan to run it super hard, but if you plan to pound on it I'd stick with 4 ohms.

I want IB in the shop really bad... having an issue with roof clearance where I want the subs as I want to manifold them to cancel driver force. Also apprehensive about the huge hole too, but hell, I can do drywall. It sure would get rid of an enormous enclosure with an 18 in it, sure could use the space.


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## chad1376 (Dec 27, 2012)

I guess another issue with roof subs is that the location is permanent. In other words, if the location causes some undesireable nodes, it would be a PITA to adjust. Some planning/modeling would be needed before whipping out the jigsaw.

That power line conditioner looks like a great idea too. My system is on the same circuit as my swamp cooler. When the motor is running, my source PC locks up. Of course it might be cheaper to just wire in a new dedicated circuit from the breaker box.


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## chad (Jun 30, 2005)

chad1376 said:


> I guess another issue with roof subs is that the location is permanent. In other words, if the location causes some undesireable nodes, it would be a PITA to adjust. Some planning/modeling would be needed before whipping out the jigsaw.
> 
> That power line conditioner looks like a great idea too. My system is on the same circuit as my swamp cooler. When the motor is running, my source PC locks up. Of course it might be cheaper to just wire in a new dedicated circuit from the breaker box.


That's a tripplite UPS, the batteries are behind it. It powers the 2 computers in there and the network in that room.. Above that is the power supply for the ham radio that also does backup switching... I do coordination for storm spotters. The audio is on it's own breaker, the bench is on another breaker. the test equipment on another. Overall there's 80A at 120V available and 50A at 240. I can convert to 3 phase with a rotary phase converter. 

I used to repair a lot of bigass ****.

I'm half spooked about the placement myself. Hell, I just replaced the DSP and have yet to get it back the way I want it. Then there's the spousal WTF factor....


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## chad1376 (Dec 27, 2012)

Well, I jumped and bought a pair of Electro Voice AP2600 amps for $150 each on eBay. I'm guessing they're early 90's vintage, but photos seem to show they were in a permanent install, with just some minor scuffs.



















I actually found "real" published specs, which don't look too shabby. Each is capable of 300wpc into 4-ohms or 600 watts bridged into 8-ohms (RMS)..plus a little headroom on top of that.

http://www.electrovoice.com/downloadfile.php?i=969646

I'm not sure if a recap on older amps like these might be necessary. if so, it'll be a fun project.


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## 2010hummerguy (Oct 7, 2009)

I power 6 Acoustic Elegance OB15's in my living room with a Peavey IPR 3000 DSP (the amp Behringer copied for the iNuke series). Gobs of power and DSP built in, I absolutely love it.

My QSC RMX2450 arrived today, will be testing it tomorrow.


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## IBcivic (Jan 6, 2009)

Nice score!


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## chad (Jun 30, 2005)

Good score man! A little searching nets you some good results in that market these days.

If the equipment cab were a hot one, you can usually tell by how things look, then a re-cap would be worth LOOKING INTO, but if not then rock it.

amps in this market are built to withstand extremes.


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## chad (Jun 30, 2005)

Architect7 said:


> I power 6 Acoustic Elegance OB15's in my living room with a Peavey IPR 3000 DSP (the amp Behringer copied for the iNuke series). Gobs of power and DSP built in, I absolutely love it.
> 
> My QSC RMX2450 arrived today, will be testing it tomorrow.


LOL holy ****, behringer copying PEAVEY... 


WOW.


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## chad1376 (Dec 27, 2012)

The only part of the deal that is not so much of a score is $50 shipping each. 

As soon as I get them, I'll pop the tops, dust the guts out and look for anything obviously suspect. I hope these tide me over for another few years. The only place to go from here is big subs and multi-kilowatt amps. I know I'm going to want that bottom octave twice as bad now.

Oh, and there were a few gorgeous Haflers on eBay that were less power and a little more money. I stared at those a long time before moving on.


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## chad (Jun 30, 2005)

chad1376 said:


> The only place to go from here is big subs and multi-kilowatt amps. I know I'm going to want that bottom octave twice as bad now.


You can pretty much count on yourself as already screwed. 

this stuff is not linear in any way 

You made a good choice, when hafflers blow up they blow up ugly.


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## chad1376 (Dec 27, 2012)

chad said:


> You can pretty much count on yourself as already screwed.


..and you're like the experienced heroin addict, showing me how to tie off my vein and heat up the spoon  I really appreciate your advice.

I guess I'll start building a rack while I'm waiting for USPS to deliver these by mule.


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## chad (Jun 30, 2005)

Ebay has cheap rack rail.

Build it at least 2X what you think you need.


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## 2010hummerguy (Oct 7, 2009)

chad said:


> LOL holy ****, behringer copying PEAVEY...
> 
> 
> WOW.


You're that surprised?


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## chad1376 (Dec 27, 2012)

chad said:


> Ebay has cheap rack rail.
> 
> Build it at least 2X what you think you need.


Man, empty rack space is just going to encourage me to buy more stuff. bad! bad! bad!

I suppose in the interim, I could fill space with my unused 3.5wpc single-ended 2A3 tube amp...just for sheer irony


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## chad (Jun 30, 2005)

Architect7 said:


> You're that surprised?


Let's say that you wanted to build a clone of a car that would be affordable, but yet enough of a clone that it would be desirable... 

You you pick the Chevrolet Caviler as the basis of your design?



chad1376 said:


> Man, empty rack space is just going to encourage me to buy more stuff. bad! bad! bad!
> 
> I suppose in the interim, I could fill space with my unused 3.5wpc single-ended 2A3 tube amp...just for sheer irony


Blank rack panels


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## 2010hummerguy (Oct 7, 2009)

chad said:


> Let's say that you wanted to build a clone of a car that would be affordable, but yet enough of a clone that it would be desirable...
> 
> You you pick the Chevrolet Caviler as the basis of your design?


I see what you're saying...that probably applies to the rest of Peavey's lineup. But the IPR and Crest Pro-Lite series are industry leaders for class D.


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## chad (Jun 30, 2005)

Architect7 said:


> *But the IPR *and Crest Pro-Lite series are *industry leaders for class D.*












Far from it.. not saying it's a bad amp, but I can say with near 100% certainty that you are not seeing them on the touring trucks.


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## chad1376 (Dec 27, 2012)

OK, I did a little research on rackmount stuff - I'm going to go full dorktard on this project.

Factory rackmount ears for my Adcom amp and Hafler Iris tuner are still available. The tuner has sat in the closet for 10-years and is completely superflous, but it'll look cool. I'll also swap my source PC into a rackmount case and get some generic add-on ears for the preamp (or maybe just a shelf)

For the actual rack, I'll probably just buy the front rails, and weld up the rest myself using some 1" square box. A little shelf for the PC Keyboard/Mouse, along with attachment points for the monitor should be pretty easy to incorporate.


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## chad (Jun 30, 2005)

Saw this coming yesterday D:

They make rack drawers with a monitor/keyboard/mouse built in.


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## 2010hummerguy (Oct 7, 2009)

chad said:


> Far from it.. not saying it's a bad amp, but I can say with near 100% certainty that you are not seeing them on the touring trucks.


Interesting, what class D stuff are you seeing in the field? Not trolling at all, I am actually very curious.


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## Viggen (May 2, 2011)

Been a adcom fan since their car audio stuff was released and thought if their car stuff is this awesome their home stuff must be better.

Its not  their home amps have no power especially down low and their sq isn't that great either. Fwiw I have a gfa-5500 which gets garage duty due to lack of oomph. The amp powers the old bic venturi speakers......


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## chad (Jun 30, 2005)

Architect7 said:


> Interesting, what class D stuff are you seeing in the field? Not trolling at all, I am actually very curious.


Lab Gruppen, Powersoft, Crown.

And WAY more self powered loudspeakers with DSP built in.


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## chad1376 (Dec 27, 2012)

chad said:


> Saw this coming yesterday D:
> 
> They make rack drawers with a monitor/keyboard/mouse built in.


..If I can find one _really_ cheap. As is typical, I'm already far exceeding my initial budget. Hmm, I should hit up our IT guy and see if he has any surpluss goodies. I did trailer his POS broken down VW Bus out of Baker CA. last summer.



Viggen said:


> Been a adcom fan since their car audio stuff was released and thought if their car stuff is this awesome their home stuff must be better.
> 
> Its not  their home amps have no power especially down low and their sq isn't that great either. Fwiw I have a gfa-5500 which gets garage duty due to lack of oomph. The amp powers the old bic venturi speakers......


I have to agree. I bought mine new on sale many years ago because it looked badass and industrial. I did expect a little more "oomph" with my garage set-up, but obviously It's left me wanting more. I expect it will sound nice on tweeter duty though (at least compared with my 80's vintage Akai hand-me-down).


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## chad (Jun 30, 2005)

I have a GFA5300 here that needs repair, it's clip/protect system on one channel is acting up... it works till you hit the limit... 

I noticed it a bit anemic.


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## jp88 (Jun 25, 2007)

You can always build the rack frame out of plywood, I built mine out of birch ply to match my desk. it has a rack mount pc along with a pre amp and amp for my computer speakers along with a few other goodies. Mid atlantic actually makes some simular equipment racks that arent nearly as well built.


My Adcom GFA 5400 seems pretty stout.


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## 2010hummerguy (Oct 7, 2009)

chad said:


> Lab Gruppen, Powersoft, Crown.
> 
> And WAY more self powered loudspeakers with DSP built in.


Gotcha, all mostly very high end amps minus the Crowns. I should have specified that I was referring to the value-driven market, especially given the context of this thread. For me it was between the Crown XLS and The Peavey IPR. The IPR blows away the XLS in everything under 100hz. Not sure what is up with Crown in recent years, I have an XS700 sitting around that is also quite weak for bass. I've heard the same is true for the XTI series. Sad because I have a lot of respect for Harman/JBL.

Mind if I ask what you do for a living with proaudio? Must be fun to be around all that great gear


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## chad (Jun 30, 2005)

The crown i-Tech is the high end side of tht market... As per crown's story they never did anything budget driven till the CE series which were HORRIBLE except the CE4K. Now they seem to have their **** together in that arena. Before the CE series the powerbase/power tech series were the "budget driven" amps but still expensive... They also rocked as they had the same design/parts as the macrotech but with many less features.

Around here the value driven market is used heavy high end stuff while the big boys hand it down after buying other stuff... it's nice to be in that market.

Was a touring FOH/Monitor/Systems engineer, in '04 I had to grow up and get a big boy job equating in less money. I worked till very recently as the electronics engineer/audio engineer/guest lecturer for the University Of Illinois, School Of Music. Now they are moving me into facilities and operations management as all of our facilities systems are now automated and I'm in tune with that ****. All while wearing an AV hat... So now my position is basically "Director Of Un-****ing things."

I still do live sound on the side and some mastering at home.... I HATE the tracking/mixing aspect of studio work, love it live.

I'm also currently project manager for a capital renovation on a 1917 building that houses our piano division/voice/and jazz studies. And that is a goddamn fiasco. It's why my time here is now sporadic and at some odd times


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## chad1376 (Dec 27, 2012)

jp88 said:


> You can always build the rack frame out of plywood, I built mine out of birch ply to match my desk. it has a rack mount pc along with a pre amp and amp for my computer speakers along with a few other goodies. Mid atlantic actually makes some simular equipment racks that arent nearly as well built.
> 
> 
> My Adcom GFA 5400 seems pretty stout.


Yah...I might just do wood construction (with rails). The main selling point is that I could paint it orange to match the speakers.


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## chad (Jun 30, 2005)

If I have the patience tonight I'll look what ebay seller I bought my rails from, they trumped Middle Atlantic's pricing and are nice, no crooked ****ty holes, etc.


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## chad1376 (Dec 27, 2012)

chad said:


> If I have the patience tonight I'll look what ebay seller I bought my rails from, they trumped Middle Atlantic's pricing and are nice, no crooked ****ty holes, etc.


If you have it handy, it would be great.

Well, I got the amps today. I popped 'em open, and after a good blast with shop air, they look virtually new inside. I didn't realize when I ordered the that one is the original model, and the the other is the "A" version. The original is definitely built to a higher spec, with two giant 10,000 mfd caps, more heat sinks and a generally more rugged looking components. 

Of course I had to "fire them up". All I can say is the sound quality stands up to any "audiophile" components out there. Absolutely transparent. The additional power allows "live" volume levels with endless headroom. I have more bass, but my speakers are at their limit. Need subs even more now. I'll never buy consumer grade equipment ever again.


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## chad1376 (Dec 27, 2012)

Just a followup on completed rackmount geekness.



There's nothing individually all that impressive, but I think the sum total is pretty cool, especially for a garage setup. I just built the rack with cheap 1/2" plywood and 2x2s. From top to bottom:

* Extra 23" flatscreen
* Fisher Studio Standard turntable - freebee from a guy at work
* Drawer for keyboard & mouse
* 2U - Fisher Studio Standard preamp - added generic rack ears
* 1.5U -Hafler Iris Tuner - I found Hafler ears on ebay
* 0.5U - Home made blank
* 4U - PC case
* 1U - Vented blank above the Adcom
* 3U - Adcom GFA-545II - tweeter duty - purchased rack ears fromAdcom
* 1U - Vented blank below the Adcom
* 3U - EV AP2600 - left woofer duty
* 3U - EV AP2600A -right woofer duty
* 2U - Blank
* 3U - Blank 
* Mini DSP - hidden behind
* External USB Soundblaster Card - hidden behind


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## jp88 (Jun 25, 2007)

nice rack. hows the back of it look?


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## chad1376 (Dec 27, 2012)

I don't know what's worse; you wanting to see it, or the fact that I took a picture before shoving it against the wall










I hard wired a bunch of outlets, with extras for future goodies. The audio equipment is on a single switch located near the turntable. The PC and monitor are always hot. The wires are not too horrid of a mess, after the liberal application of zip ties.


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## chad (Jun 30, 2005)

Nice, you went balls deep into that!


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## jp88 (Jun 25, 2007)

I do quite a bit of a/v rack work and Im a bit OCD.


chad1376 said:


> I don't know what's worse; you wanting to see it, or the fact that I took a picture before shoving it against the wall
> 
> 
> 
> ...


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## chad (Jun 30, 2005)

chad1376 said:


> The audio equipment is on a single switch located near the turntable.


What kind of switch? the inrush of those amps may be pretty huge unless there is a soft-start.


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## chad1376 (Dec 27, 2012)

It's a dual 15-amp wall switch (2 parallel 15 amp circuits). Turn on doesn't seem to be a problem. I noticed the internal relays in the amps click on at slightly different Times, so that probably helps.


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## chad (Jun 30, 2005)

That click is one of 2 things, speakers being activated, or the soft start going full bore....

If it is the first then there is no soft start.


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## chad1376 (Dec 27, 2012)

Not to be a thread whore, but I haven't come across any forums dedicated to ugly / over the top DIY garage systems with pro-sound influence. So, I thought I'd beat this thread into the ground with expansion progress.

After some searching, I've found plans for an easy to build, economical horn sub here:
Lilmike's Cinema F-20

It's big, and have a spot in my Garage for one..but why build one, when I can build two for twice the price. I have no idea yet where I'll fit the second.

I plan on slicing up plywood this weekend. I'll post up progress pic's when I get started.


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## chad1376 (Dec 27, 2012)

Some progress on the big horn sub. I decided one is probably enough for now.


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## chad (Jun 30, 2005)

Mad respect sir.


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## chad1376 (Dec 27, 2012)

Some more progress. Of course I had to keep the orange theme going.










I have a stereo 3-way 24 db/octave pro sound crossover and a Dayton 15" DVC sub on the way to wrap this up. I'll continue to use the MiniDSP in the tape loop for EQ, but not crossover duty. Hopefully, I'll get to try it out next weekend.

I don't think I'll need more amps. I'll use one of the EV's for mids (200 wpc into8- ohms), and the other for the sub.


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## BP1Fanatic (Jan 10, 2010)

Nice!!! I have you tried it out yet?


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## chad1376 (Dec 27, 2012)

BP1Fanatic said:


> Nice!!! I have you tried it out yet?


Yes, but it needs a lot of tweaking to integrate nicely with the line arrays. I located the sub in the corner of the garage, and it is very powerfull and deep. Unfortunately, it's next to my pile 'o scrap metal, paint can shelves and other assorted loose and clanky things. With some songs, I hear as much rattling as bass. And, it will vibrate my stuff off the shelves.

The responce is a bit lumpy too, probably more due to the location than the actual performance of the sub. I might try to move it somewhere else, unfortunatlely, I don't really have any other place to put it without spending a month re-arranging all my crap.


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## BP1Fanatic (Jan 10, 2010)

That's how I have my horn positioned in my mancave. I initially had it firing into the corner, but the frequency response wasn't as flat. It was a lot louder tho'!


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## PGT FTW (Oct 19, 2009)

I've got a Behringer EP4000 running four 18" subwoofers in a line array, at 2 ohms stereo. Its got PLENTY of balls. That said, I really like the Crown XLS series if you want an active crossover....not much more $$ these days over the Behringer.


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## chad (Jun 30, 2005)

4X18" is not really a line array per say.. it's merely a line of subs as it is exhibiting no directivity control at sub frequencies... 

But they couple like a motherfucker.


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## BP1Fanatic (Jan 10, 2010)

Lol!


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