Recommendations for getting flat response down to ~23hz for around $400.

[JoeyJoJo]

In the past few days I've been learning quickly about subwoofers, starting from essentially know nothing, although I have a physics background.

My interest is to play electronic music genres that feature sub-bass (23-30hz) in a small room (~2000 cubic feet) at home for dancing purposes.

The maximum output in dB is not very important.

A flat (+- 3dB) response over the 23-40hz range during a sine sweep (not accounting for room normal modes) is very important. Indeed some of my favorite tracks to listen to use similar sine sweeps.

Ideally it would weigh less than 50 pounds, and be smaller than 3 cubic feet. And self-contained, without need of external amplifiers or external DSP.

Also ideally it would be premade.

I've looked into DIY, and it seems for my purposes I would gravitate towards building a low-tuned port system using a plate amplifier with built-in DSP (minidsp and dayton audio), but it would be nice if I could order a premade solution that "just works" (especially since I have never built a subwoofer before).

Sorry if I'm asking for the impossible, anything even close to what I'm asking for would be great. I'm very attracted to SVS's line of "smart" subwoofers with DSP / EQ functionalities built-in, but they're about $300 more than I'm willing to pay.

 

 

[SME]

"The maximum output in dB is not very important. "

But it *is very important*.  It's always very important because it has by far the greatest impact on other trade-offs like size and cost.  With that said, there are a variety of DIY and commercial options that can get you started, and you shouldn't have much trouble getting decent output for moderate music listening for the range you indicated in a fairly small room like yours.

I'm reluctant to name brands because I'll probably leave out someone relevant, but off the top of my head, I can think of Power Sound Audio, Hsu Research, Rhythmic, and Monoprice as being potential sources of high-value/budget consumer offerings, similar to SVS.  I don't know what kind of DSP capability any of them offer these days though.

Depending on how you value your time and labor, a DIY sub can get you a lot more for your money than anything you can buy.  It also gives you the opportunity to focus the design better for your needs.  For example, a larger sub may be more feasible for your room if you can design it to fit the footprint you have available.

As far as sub type, vented typically offer more output for the money than sealed but at the cost of size.  Vented subs also roll-off much more rapidly below the bottom end of the bandwidth, and typically require a high-pass filter to protect them from excessive content below their capability.  Subs from the aforementioned vendors provide DSP for this, even if they don't provide user accessible controls.
 

My last piece of advice is to give serious consideration to two subs instead of one.  When placed in different parts of the room, two subs typically offer much better sound quality than just one, for a few reasons having to do with room interactions.

[JoeyJoJo]

Thank you so much for mentioning Rythmik, I hadn't heard about them and I think I just fell in love. Their 12 inch servo subs are slightly beyond my price range but servo technology sounds promising. The L12 for $560 is almost exactly what I'm looking for, 18hz@-3dB, 300 watts, and I think it weights about 50 pounds . I'm going to wait on the decision, but it seems like an amazing subwoofer. The competition would be the ~$640 SVS SB2000, which is sexier, 19hz@-3dB 500 watts 34.8 pounds.

[kipman725]

Flat frequency response is not the most important characteristic considering that room modes have far greater effect.  Most people here are running room equalization and house curves so beyond giving an indication of the minimum frequency where sufficient output can be coaxed from the sub the frequency response isn't very important.  A flat measured in room response will sound thin and overly bright on electronic music, a typical house curve would be -1dB/octave for general purpose playback but I would add significantly more bass boost for playback at 'party levels' (~95dB A weighted average) of electronic music.

[JoeyJoJo]

Yeah I was wondering about that kipman. Perhaps it is more cost effective to get (or build) a compact 12 inch sub with a not very flat response but high excursion capabilities or low-tuned radiator making the sub capable of decent 20hz output and just equalize it. I know how to equalize in software running on a computer, but haven't looked into how to equalize using a dedicated module to process the audio input into the subwoofer, downside being an extra piece of equipment. How would EQ work?

Commercially-available I haven't seen many subs that give me hope they can produce 20hz that are also cheap and compact. Generally the cheaper subs give very little technical data at all.

[peniku8]

I use EqualizerAPO to calibrate systems in rooms which don‘t have outboard dsp. You can export txt files from the Equalizer in REW and import those to APO, it‘s great.

I‘m running the cheapest 12“ Klipsch sub as backup subwoofer and it‘s pretty much flat in my room down to 20Hz or so. It will compress quickly, but if you only want moderate listening levels it would be fine I guess.

[SME]

On 5/4/2020 at 2:34 AM, JoeyJoJo said:

Thank you so much for mentioning Rythmik, I hadn't heard about them and I think I just fell in love. Their 12 inch servo subs are slightly beyond my price range but servo technology sounds promising. The L12 for $560 is almost exactly what I'm looking for, 18hz@-3dB, 300 watts, and I think it weights about 50 pounds . I'm going to wait on the decision, but it seems like an amazing subwoofer. The competition would be the ~$640 SVS SB2000, which is sexier, 19hz@-3dB 500 watts 34.8 pounds.

Servo technology reduces subwoofer non-linear distortion substantially when the sub is being pushed to its limits.  Below that point, the difference is not as likely to be appreciated, and above that point, the sub runs out of travel completely just like any other sub does.  If you want lower distortion, it's usually better to have enough displacement headroom so that you aren't driving the subs near their limits much if at all.  Another thing is that most servo solutions probably control lower harmonics better than higher harmonics, but the higher harmonics are probably much more important, perceptually speaking.  Of course sometimes you have to compromise, and servo technology has its niches.  Just don't expect any major SQ improvement from it.  The whole sub system design, especially including SPL capability is important.

17 hours ago, JoeyJoJo said:

Commercially-available I haven't seen many subs that give me hope they can produce 20hz that are also cheap and compact. Generally the cheaper subs give very little technical data at all.

I would say there is a primary three-way compromise between *cheap*, *compact* and  *low-and-loud*; pick any two.  Low-and-loud are one in the same because it's pretty easy to make something tiny play loud if you don't care how low it goes, and you can technically EQ any system to be "flat" as long as you never turn up the volume high enough to hear anything.

[kipman725]

It sounds like you don't have much space in which case the most compact solution would be equalized sealed boxes.  Multiple subs are one of the best sound quality improvements so for home use I would prioritize more smaller subs over a single large sub.  Outboard DSP/DSP amps are quite easy to use, you can just enter the coefficients from REW into the parametric EQ.  Berhinger Inuke/NX are powerful and cheap but have noisy fans so you would want to locate them in another room.  There are also plate amplifiers with DSP available which could be an option if you don't want any large/nosiy equipment.

[JoeyJoJo]

You guys are right-on, thank you. I ended up getting a $100 subwoofer on craigslist (200W Energy S10.3) just to play around with, and equalizing it with REW via computer soundcard (EqualizerAPO) made me realize that flatness, as you guys stated, is better off parametrically-EQ'd and the non-EQ response of the sub doesn't matter much. With low-frequency capability being determined primarily by maximum driver excursion (expensive) and surface area (big) of the driver (and low-tuned resonance if applicable i.e. port (big) or passive radiator (expensive)), you have to choose expensive or big, as you guys also stated. For instance the Energy S10.3 supposedly has unusually-low-freq capabilities for its price, but that 10" driver is on a 2.5 cubic-foot ported box (wonder what freq the box is tuned to?).

For an outboard / standalone DSP, is it really as simple as buying a $90 miniDSP (or better recommendation?) and uploading the REW coefficients? The craigslist purchase came with a crap budget soundbar. REW did a really good job of matching the SPL between the sub and soundbar despite the sub not having a volume/gain knob, would be nice to get parametric EQ without requiring my laptop.

[klipsch]

Minidsp are a good way to go. It may already be known, but a software license is needed with the minidsp hardware. If buying used or new, it can sometimes not be included. I've been running a 2x4 for 10+ years and a 10x10 for over 7.

[kipman725]

Pro gear like Behringer DCX2496, Symetrix 8x8 DSP, QSC QSys are often better value for money especially second hand.  I run an 8x8 DSP which I have modified for silent operation by replacing the top of the box with mesh and replacing the fan (by using a 12V fan and a 24->12V buck converter).