DIY Subwoofer - what amp to use?

[SKE]

Dear audiophiles,

recently I was trying to build myself a Subwoofer. As ist turned out the amp (Monacor SAM500D) I got for the build died prematurely (see my other thread ), so I will have to start over. So far I have a 12" ScanSpeak woofer and an enforced closed wooden box with a volume of about 120 liters. So I will need some amp to power it now. I might have to add, that this is my very first DIY speaker, so maybe I didn't plan the amp part well enough in the first place. I just got the Monacor since I got a "good deal" on it. During the process of building it I got thinking that maybe it would be even more reasonable to not add a classic subwoofer amp like the Monacor to my cabinet but rather use an external one.

A few words on my current setup: I am using a Wiim Pro as a streamer feeding optical to a Quadral A10s amp. The amp powers a pair of Quadral Galan (or Heco Direkt) and I use the Wiim's equalizer settings for basic DSP. The Quadral A10s has no subwoofer out, but it does have a "pre-out" which I was intending to plug the Subwoofer to. Obviously I will need a crossover of some sort to feed the low frequencies to my sub. So the question is how to proceed now. I can think of several options (maybe you guys can even add a better one or help me choose):

- Get a classic Subwoofer amp which brings a crossover and maybe even DSP and add it to the box. Just one that works (better than the Monacor ). Which one? Maybe even the low frequency DSP part can be done well enough by the wiim
- Get an external amp. Which one? I recently found the Yamaha px5 which looks interesting since it has enough power and DSP and should do the Job. I could not find any reasonable reviews on this particular one. It would offer the possibility to add a second subwoofer later on if necessary.
- Get a basic internal/external amp with no particular features (which one?) and add a "reasonable" DSP to the system like a MiniDSP Flex to provide signal to both amps stereo + sub(s). I was considering to add some better DSP to my system anyway. Maybe it is more reasonable to have such a "central DSP system" as opposed to add several components that somehow do DSP
- Something completely different?

 

[Yevhen]

I used a 200W TI-based class D amp from AliExpress with an additional RC filter. Works perfect with SB acoustic 12" sub.

Do you really need a DSP for a low-pass filter? A 10 cent R-C filter in front of the amp will do the same job

 

[DVDdoug]

recently I was trying to build myself a Subwoofer.

The first thing is speaker design software to optimize a driver and sealed or ported cabinet together. WinISD is free.

feeding optical to a Quadral A10s amp

You need line-level signals (analog) for an active crossover.

The miniDSP seems popular around here.

A "pro" crossover with knobs is easy to use but you might to make sure it has unbalanced connections, or that it can work with unbalanced connections.

Or some plate amplifiers have a pass-through crossover.

The most common solution is to use an AVR which will have a line-level sub output and then it can also decode and use the LFE channel in movies.

Some plate amps also have EQ adjustments (usually analog but sometimes DSP). That can help to extend the bass, especially with a sealed box. (If you boost the deep bass in a ported-box, which rolls-off steeper, the woofer tends to flop around without put-out much sound.)

recently found the Yamaha px5 which looks interesting since it has enough power and DSP

This type of pro amplifier can be configured as half a crossover. You can high-pass one amplifier for the main speakers and low-pass another one for the woofers, or bandpass for the midrange(s) etc.

 

[Dumu]

I really like the Fosi audio TP-02 amps for diy subs. I own 3x and they are just perfect for home use. Never run out of power and the adjustable low pass works well if you have to input full range signal.

I also have a reckhorn A-409 that has some nice EQ and phase options, but for some reason there is some weird distortion in the output. Don't know if it just my unit that is bad or if all of them are like that... otherwise the reckhorn would be a really nice package.

 

[Flaesh]

it would be even more reasonable to not add a classic subwoofer amp like the Monacor to my cabinet but rather use an external one

Yes.
And external processor.

 

[levimax]

I recently built a couple of large subwoofers and purposely wanted an external amp with NO DSP. During the integration process it is much easier to have a "central" DSP like Mini-DSP or a PC, otherwise you can end up "fighting" all the "DSP black boxes" and their added latencies and other undefeatable features. I ended up with one of these from an Ebay seller, it is a 1,300 watt per channel Crown amp and works perfectly. These are brand new in the box. I think people get scared away because they are "Real Cinema Amps" designed to be used with a proprietary processor but you don't need it. On their own they are just a plain "power amp". You do need to wire up your own balanced connector (included in the box) but that is easy. Might be worth a look (seller will take less than asking price). https://www.ebay.com/itm/364056130409?_skw=CROWN+xlc21300&itmmeta=01K1Y39BA51F4K536N29HG940R&hash=item54c36fb369:g:SFAAAOSw2g9jBnxP&itmprp=enc:AQAKAAAA0FkggFvd1GGDu0w3yXCmi1feDdIWyZ1Se/uKWlm/kQsppVZ5QlnXiEqYENKhbU/Hzv0vSi8ntuYexeogevuJCZDkTTw63k5G4CRt6psX4OKY5LU/0p363YXluZBA3EJtJVHaHBQFK5A3MQLaNfy8bvdgHUY1TLSlbaa+tdvFw6iHGyYLeDO43BdrePn/NoL2bsPszne0x9zWd0GjgTd6+607DUeM8b7my32F0WIFDx/UddjVxrpKbgrsyCLQVZhqtrwTMcUzeO3Cas8JDkVGSNk=|tkp:Bk9SR5a1pcOPZg

 

[jamescarter1982]

I really like the Fosi audio TP-02 amps for diy subs. I own 3x and they are just perfect for home use. Never run out of power and the adjustable low pass works well if you have to input full range signal.

I also have a reckhorn A-409 that has some nice EQ and phase options, but for some reason there is some weird distortion in the output. Don't know if it just my unit that is bad or if all of them are like that... otherwise the reckhorn would be a really nice package.

that's interesting . hadn't noticed these . they look around £40 is that correct ? did you buy direct from aliexpress ? seems like a really affordable option for active multi way speakers

 

[Dumu]

The last one I bought from amazon (75€ incl. shipping), can't remember where the earlier ones where (I think they were a bit cheaper then). I really like them. They are tiny but have plenty of power and I think you could get even more with different power supply. At idle they are dead silent and not even warm to the touch.

 

[Yevhen]

that's interesting . hadn't noticed these . they look around £40 is that correct ? did you buy direct from aliexpress ? seems like a really affordable option for active multi way speakers

40 is without the power supply

 

[Yevhen]

active multi way speakers

Do you mean the active speaker with something like bi-amping? I also was considering a class D for the midbass and class AB (LM3886?) for the tweeter

 

[jamescarter1982]

yeah that's what I meant just looking around at affordable options that would be reasonably easy to integrate into a case or built into a stand or something like that . like the look of the 3e audio boards but the cost adds up quickly . atm use a pioneer ax10i cinema amp and a pro amp for the bass but it isn't exactly compact