I believe it's because it's cheaper than a plate amplifier, easier to work with. You can, however, install a plate amp on a DIY sub.

Example: http://www.parts-express.com/cat/subwoofer-plate-amplifiers/332

I think it's a lot easier to drill a hole for a neutrik/speakon connection rather than a perfect fit for a plate amp.

 

I believe it's because it's cheaper than a plate amplifier, easier to work with. You can, however, install a plate amp on a DIY sub.

Example: Home

I think it's a lot easier to drill a hole for a neutrik/speakon connection rather than a perfect fit for a plate amp.

as a manufacturer myself, I can assure you that nothing is cheaper than a plate amplifier for the subwoofer. If it's going to be a freestanding amp, it's going to need a chassis. That will increase the cost dramatically. Subs with outboard amps have specific uses and applications but rarely sell in the consumer world.

My giant DIY sub already weighs too much and routing a perfect hole is often daunting to hobbyists. I also never know the correct positioning until I find a place to put it. I don't know which way the amp will be facing, depending on how the port is positioned.

 

Being able to run multiples on a single amp is a huge deal in and of itself. In most cases we're using amps that push over 1kW per channel. Two plate amps at 1kW RMS (that can actually deliver that, not just claim it) would run you up between $600 and $1k by themselves.

So essentially, you'll pay more for just the amps than you pay for the entire project if you go with a pro-amp.

Also, this way we can put the sub amp in our amp racks, not need to find an outlet or run long RCA cables to where the subs sit, and have a lot more flexibility in placement.

 

Rack amps are cheaper, better, more powerful, less hot, and more reliable than plate amps.

 

Right on the first, not on the rest.

http://www.speakerpower.net/sp1-mono-models.html

 

With a plate amp you would have to run rca cable to the sub for input. When subs are placed throughout the room a lot of times they can get quite a ways away from the receiver. Monoprice.com has cheap rca cables but hiding an rca cable is a little more difficult than hiding speaker wire. With a Pro amp you just have to run speaker wire to the sub.

Just read what @STL D wrote and would echo his reasons. Another would be that some of the Pro amps offer DSP and crossovers to help make the sub sound the best in room that you place it in.

 

Subs produce heat and the amp in the sub expose the electronics to the heat. The box would also have to be a bit larger to account for the internal volume of the sub.

 

Yea as a Electrical engineer, cooling on high power electronics is a real challenge. DIY means you want the easiest thermal setup, not having it in a box optimizes the cooling and means you don't need to analyze the air/thermal flow in your box, external is the way to go.

 

A better question is why do most commercial subs have on-board amplification? It's because when they were fist introduced there was no practical method of powering them from the existing receiver or amp, so they came self-powered. That was the most convenient way to power them, but by no means the best. The number one reason not to self-power subs is that the resulting long interconnects and the distance between where the receiver and subs plug into the wall is a recipe for introducing ground loop noise. Keeping the all of the electronics in the same place is the best practice. I use a plate amp, it's in the same book case as the rest of my electronics.

 

I need 11 channels of 4000watts to run all my subs. The only plate amp that comes close would be 11 4kw speakerpower plates, but that costs as much as a new car... like $28,000 in amps or whatnot, and then taxes and shipping.

Or I could spend $5000 on LG FP14k clones and still get a great amount of power... it's 2 channel and less than half the price!
Or if you needed 12 channels of 2kW then get 3 FP10k's, for just over $3000.

No need to pay tens of thousands, or suffer with just 1000watt plate amps with no clipping indicator and bad cooling.

and most plate amps don't have DSP for the DSP pro-amp users. No limiter, no digital LPF/HPF XO's, no PEQ, no DEQ, no clipping LED, no input/output monitoring. Just some limited analog circuits of questionable quality.

 

The last plate amp I had was a ED 1300watt. Which I overheated and almost smoked on me (Hey... I like my bass!!!)
I told myself, never-again!

 

I have a DIY kit with a plate amp, $235 for the Reference 15 combo and another $100 for the plate amp.

http://www.parts-express.com/dayton....com/dayton-audio-15-reference-series-ho-subwoofer-and-cabinet-bundle--300-7093

http://www.parts-express.com/yung-s...500-6-500w-class-d-subwoofer-plate-amplifier-module-with-6-db-at-25-hz--301-514

Instead of paying the $239 for the Yung 500w amp, I found one used for $100. I went slightly over my $300 budget so for $339 I got an outstanding sub perfectly matched to the Yung plate amp. I used my jig saw along the pre-marked cutout for the amp, and because the amp has a seal it fit perfectly and does not leak. I could have paid another $30 for the Ultimax 15 combo but it used more power, so the Reference 15 was a good match.

If I wanted a pair of subs, I would have gone with the Ultimax 15 series and used an Inuke 3000 to give each Umax the 800 watts it wants.

I set my budget and stayed within 10%. So sue me, I'm cheap. (but very happy with my plate amp sub)

 

Q: Why are all the amps in DIY subs external?


A: Because Behringer doesn't make a plate amp.


;-)

 

Are you implying there is brand loyalty to Behringer or just that people who use iNukes for budgetary reasons are idiots?

 

To add to all the above plate amps can produce sealing issues and some of them aren't even sealed themselves, some leak a little, some leak a LOT. Unless one is going for a super budget build and using one of the really inexpensive plate amps they rarely make go fiscal sense.

 

This to me is the best reason. Go through all the effort to seal and stiffen a massive, heavy, cabinet and then cut a 10” hole in it for a plate amp just seems beyond stupid.

 

Adding a plate amp is extra work, a signle external pro amp can power multiple subs, and some plate amps (like the one from PE) have a HPF which e.g. won't allow a sealed sub to go below 18Hz.

I think those are some of the reasons. Also a lot of the DIY community is based on tradition, if someone comes up with a good integrated amp solution and its popular, you'll see more of those.

 

If you're building your own sub, nothing stops you from attaching a 2U bay to hold the amp, if you want to contain everything in the same cube. The degree to which it's tacked on or finely integrated is up to you, and it can still power other boxes. Obviously Bill F's caveats still come into play.

 

though it was never popular, the ax6240
http://www.parts-express.com/behrin...r-eurocom-ax6240-2900w-2-ohm-dual-amplifier-w-dsp-usb-ethernet-control--247-018


had a remote power feature:

http://www.parts-express.com/pedocs/specs/247-018-behringer-ax6240-specifications.pdf


didn't look too bad either. maybe they should just put the 6000dsp in that box, quiet fans and call it their "install" product.

 

The specs on that actually seem pretty solid. They claim 1500W RMS per channel into 2 ohms, and it's bridgable. Possibly the same DSP unit as well, based on the specs. Why aren't more people using this?

 

I find plate amps to be convenient and effective. I have one in my DIY sub.

 

@rhodesj
not sure. it was a strange product. i don't know if it ever made the main page on behringer's website in the amp section. i suspect that most folks never knew about it.


personally, i think they should go back to old school flow-through with real heat sinks. even though they pretend that they don't, the amps make some heat that needs to be removed. even a minimalist approach could help.

then there is that "face". lol. gotta do something about that.


old school meets new school.

 

Just received to AX6240 amps. Haven't put them in the rack yet but they are definitely better looking than the iNuke and quite a bit heavier- 21# each (class-H vs class-D)


via Tapatalk

 

I'd really appreciate it if you could fire them up and report back, particularly on fan noise. These are looking like a nicer alternative to the iNukes, with remote power on and ethernet control (and much better looks) but I can't find where anybody has commented on how noisy the fans are in a home environment.

 

Those AX6240 amps look nice. Wish they used those cases for the inukes.

 

I wanted bang for the buck only so far as I was not going to suffer with impaired sound quality/performance, it took some research and asking questions on this forum. I remember pricing plate amps to go with my twin sealed 18" Ultramax subs and it would have been considerably higher than the iNuke6000DSP rack amp I ended up with. For a meager investment it drives both subs and does so quite well. I would say if cost is not a significant factor go for the plate amps you want but if your balancing a budget each month than the rack amp simply can not be beat.

 

having a plate amp behind a false wall in a dedicated theater is a PIA if you want to tweak the settings. Given the choice I would always put the amp in the equipment stack.

 

I don't like cutting plate-amp holes into a sub I built. If the plate amp dies and want to replace with a different model, you have some modification to do. Or if you want to upgrade to a pro amp, same deal.

I find it better to wire with a speakon, even if using a plate amp. My last plate amp I bought got it's own box. This picture was when I made the box. After a block party and a few backyard parties running a F-20, it got holes drilled for airflow, box started to get warm.

 

Behringer is the McDonalds of amplifiers, minus the food safety checks.
They are cheap, fast, readily available, and keeps just-enough mystery-meat in your stomach to keep it from eating itself into total-starvation.

The Crown 4x3500 is designed to withstand severe and sustained and repeated brownouts and power surges 80-300 volts and still keep ticking, the amp is smart enough to reduce the output power to keep the show playing as best as technologically possible;
While the Behringer just turns off or explodes, but only after it clips and melts your coils. hehe

Behringer is not a quality hamburger, there is lots of asbestos, glass and metal in the meat, and it will kill you within a month if that is the only thing you ingest. haha hehe hoho

Powersoft, Crown, QSC, Gruppen are far less likely to burn your house down while you are sleeping, or lighting the rack on fire when booming it.

 

lol, that's quite the analogy. They're not going to burn your house down though.

 

DIY subs will come and go but a good rack amp will last for decades. I've gone with separate amps for subs for over 20 years and have not even once wished my amp were attached to the sub in some way.

 

OK, so to sum up... Why are all DIY amps external? Well, they're not ALL external...

I've built a few subs. Some are pro-audio, and those use external amps, as is convention for pro-audio. I've built some car subs, and those use external amps for the same reason.

OTOH, I've built a couple powered speaker sets for desk / PC use. Those use plate amps, as is convention for powered speakers. (I even built my own amps, because hey... DIY, right?)

I haven't built any HT subs -- yet -- but if/when I do, I would plate-amp them if I were giving them to someone else, because most HT receivers only give you a line-level output, and the recipient is not likely to want to build a 19" rack just to suit this one sub. For myself, it would be decided based on what else I had going on. I like plate amps, and I like rack amps. They're both perfectly fine.

My current home sub is a commercial box I've had for some 10 years or so. Plate amp. Still works wonderfully.

Stepping away from the religious debate for a moment, there are pros and cons to each form factor, of course.

Plates are somewhat limited in their footprint, and are subject to mechanical stresses. I've taken to building an "amp chamber" in my self-powered sub boxes, so there's no real concern about air leaks. It's not too hard to flush-mount a plate with a router, but rounded corners can be tricky. I've never had any problem with ground loops, and I don't know exactly where you're going to find a "loop" with usually ONE connection to the AV system... (The power supply should be galvanically-isolated from the AC mains afterall.)

Racks open up possibilities for swapping the power-plant without modification to an enclosure, which is nice if you're prone to tweaking things. The market is more competitive, which means wider variety, and potentially lower costs. You (that is, the manufacturer) can actively cool a plate just as easily as a rack, if you're OK with fan noise. If you're not, the plate may win on based on having vertical fins exposed to air -- that, and I've never seen anyone put a glass door in front of a sub enclosure. So I'm not sure cooling is all roses and sunshine either way. Finally, depending on the amp, you may have to expand your connector vocabulary a bit. (XLR? Speakon? Balanced inputs? Whassat, now?) Not insurmountable, and Speakons in particular are actually quite nice.

Sure, there aren't too many plate amps that put out enough power to turn your driver's voice coil into a backup cook-top, and therefore practicality might be a deciding factor in a few cases. Otherwise... I'd say it's pretty much down to one thing: It's a little easier to build a box with one hole in it, than one with two holes in it*, and people are inherently lazy.

(*: Plus/minus one or two for ports, terminal cups, etc...)

 

Having owned subs with plate amps and passive subs with external amps, I can't say that I miss the subs with plate amps. Moving a huge heavy sub around to access the amp is not fun, and it's just a waste of time when all of that could be in the rack with everything else. I also don't see the need for separate DSP when that can and will be programmed into something like a MiniDSP.

So ideally it should just be Processor > DSP (if not built into processor) > standalone amp with fixed gain and no DSP > subwoofer