BTW, I really am straying into solutions. I am not saying you can't get good without a high pass filter, but rather, I find it a lot easier to get there.
In this sense, I'm 100% with Richard Vandersteen. :)
Subwoofer speed is in the room, not the box
First, if you like swarm, that’s fine, please start a thread somewhere else about how much you like swarm.
I want to talk about the impression that subs are fast or slow compared to planar or line sources.
The concern, and it’s correct, is that adding a subwoofer to say a Martin Logan or Magneplanar speaker will ruin the sound balance. That concern is absolutely a valid one and can happen with almost any speaker, not just speakers with tight dispersion control.
What usually happens is that the room, sub and main speakers aren’t integrating very well. Unfortunately for most audiophiles, it’s very hard to figure out exactly what is wrong without measurements or EQ capabilities in the subwoofer to help you.
So, there’s the myth of a small sub being "faster." It isn’t. It’s slower has worst distortion and lower output than a larger sub but what it does is it doesn’t go down deep enough to wake the dragons.
The biggest problems I’ve heard/seen have been excessively large peaks in the subwoofer range. Sometimes those peaks put out 20x more power into a room than the rest of the subwoofer. Think about that!! Your 1000 W sub is putting out 20,000 watts worth of power in some very narrow bands. Of course that will sound bad and muddied. The combination of sub and main speaker can also excessively accentuate the area where they meet, not to mention nulls.
A lot is made about nulls in the bass but honestly IMHO, those are the least of our worries. Of course too many of them can make the bass drop out, but in practicality is is the irregular bass response and the massive peaks that most prevent any good sub from functioning well in a room.
Bass traps are of course very useful tools to help tame peaks and nulls. They can enable EQ in ways you can’t do without it. If your main speakers are ported, plug them. Us the AM Acoustics room mode simulator to help you place your speakers and listening location.
Lastly, using a subwoofer to only fill in 20 Hz range is nonsense. Go big or go home. Use a sub at least at 60 Hz or higher. Use a single cap to create a high pass filter. Use EQ on the subwoofer at least. Get bass traps. Measure, for heaven’s sake measure and stop imagining you know a thing about your speaker or subwoofer’s response in the room because you don’t. Once that speaker arrives in the room it’s a completely different animal than it was in the showroom or in the spec sheet.
Lastly, if your room is excessively reflective, you don’t need a sub, you need more absorption. By lowering the mid-hi energy levels in a room the bass will appear like an old Spanish galleon at low tide.
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@mijostyn wrote:
Exactly.
Bring on the pictorial!
You mean as a horizontally configured subs array?
If addressing the full audible frequency spectrum the problem to me is not a point source being a point source, but rather merging more of them and instead have a single ditto cover a suitably wide range to minimize issues. That’s what’s I do having a single point source from just over 600Hz all the way up to about 17-18kHz, while - importantly - controlling directivity down to the crossover region with a fittingly large horn for a smooth dispersion pattern transition to the vertically mounted woofers below. Next step, in theory at least, would be a Synergy horn for a single point source all the way down to the 100Hz, if proper energy coherence can be maintained handing over to the subs - certainly when thinking of the lack of a dedicated midbass section.
My aim is for at least 20dB headroom in the bass region on top of the max. desired SPL level. That’s when efficiency comes in handy, at the expense of size (and, ultimately, ultra low end extension), but sonically it makes a difference few have experienced. Yours is simply a different approach with multiple woofers and a bucket load more power that’s needed here, but you’ll have even deeper extension (flat to 15-ish Hz?) and a no doubt excellent performance in the lower octaves when dialed in. Honestly, I’ve never much cared about the sound of curved line arrays at concerts. They very generally lack midbass presens and impact. I would have preferred the industry officials here cared more about sound than catering to install convenience from smaller boxes and being indifferent to power requirements. Moreover, the variety of bass horns I’ve heard from concerts are vastly better sounding than those typically dual 18" ported subs with their pounding out one-note LF, which is just tiring.
It comes down to listening evaluations eventually. If it works out with higher high-pass, it works out. If not, ~85Hz is where it’ll remain.
My gripe with ESL’s in general has been a lack of overall substance or density to their sound, certainly compared to larger horn variants or hybrid iterations with large woofers. To you that may be about cone-based speakers being too thick (i.e.: slow) sounding, but to me it’s about what lends itself more naturally to my ears. Never heard those Sound Labs - they may be different in this regard due to their sheer size and ceiling-to-floor termination. With regard to large woofers (say, 15") as mids, they do cover less range upwards compared to smaller drivers for them to really be called midrange drivers, but importantly they have a power region fullness and realism here that smaller drivers can only dream of. It’s no comparison, period (when they’re high-passed accordingly they’re even low mids rockets, and run actively will give you another level), so all that talk about smaller drivers being more ideal as mids, when also going down into the upper bass area, fails to take both of these aspects into consideration. ESL’s when large enough, or so I gather, are no doubt different beasts with regard to speed and lack of inertia.
If you cross the subs at 100Hz the subs can be localized no matter how steep the slopes. My subs are positioned close to and symmetrically to the mains and configured in stereo, so no issues here. And I fully agree; when the subs are dialed in correctly it’s just a coherent of-a-piece presentation. I love how the lower octaves "morph" effortlessly in intensity and presence depending on the material. Great bass just "happens" in the air, right in front of you between the speakers or as this immersive presence. |
@phusis The Sound quality at stadium concerts is in general awful, but that is not the point. The line arrays project power better which is what it is all about at these concerts. Exactly, the horizontal array of subwoofers forms a horizontal line source. Who says a line source has to be vertical? If the subs are stereo, they are matched to the main speakers in time and phase, and the volume is set correctly you can not localize a sub running up to 100 kHz rolled off at 48 dB/oct. If you could I would not be using that combination. There is no such thing as too much head room:-) There is nothing wrong with a proper point source system. The image will be smaller and the acoustic power will roll off faster with distance. All other aspects of sound quality are the same. Many people prefer the point source presentation. They do not like sitting up front. That is the usual complaint with ESLs, they are too polite and if you make them do low bass you are correct. THEY HATE MAKING BASS! Which is why I got into subwoofers back in 1978. I had Acoustat X's and they were way too polite. Taking 100 Hz and below away from them unleashes a lion. With an 8 foot tall line source ESL in a room with an 8 foot ceilings they are more powerful than most horn systems, but they do not go as loud. I can get up to 105 dB and that is it. The ESLs do not give up. I run out of power. By more powerful I mean things like snare drum snaps and bass drum kicks have more visceral content. The problem for ESLs is, to get reasonable efficiency the stators have to be as close to the diaphragm as possible and the diaphragm has to be stretched tight. There is no suspension. Thus, an ESL does not have enough space or compliance to make low bass at volume. The diaphragm excursions are too long for them. But, take 100 Hz and below away from them and you can not see the diaphragm move at all. The only limiting factor is transformer saturation. The Sound Labs have two transformers separated by a 6 dB/oct xover at 5 kHz. I am going to remove that crossover and use another amp and a digital xover to run the high frequency transformer. The major benefit of both our systems is the controlled directivity of both horns and dipole line sources, minimizing room interaction which produces a much finer image. Both have ultra low distortion. Because of their efficiency, horns will go louder and require much less power to do it. The ESLs will produce a larger image moving you to the front of the venue. All roads can lead to Rome if close attention is given to every aspect of performance from cartridge alignment to matching the amps correctly to proper control of room acoustics. It is much, much easier to obtain great results with a digital preamp in both systems. Having complete control over frequency response allows one to match the channels perfectly obtaining the best image obtainable. Digital crossovers are superior to analog ones and jacking the bass at 6 dB/Oct below 100 Hz produces lifelike results at reasonable ear saving volumes. |
That is a neat trick to use with lower frequencies ( = long-enough wavelengths in-room)! Especially considering the lateral boundaries ( = sidewalls) will be of similar/same composition ( = permeability / reflectivity to lower frequencies) more often than not.
I’m surprised that composition of room boundaries hasn’t come up yet. Of the subwoofer “speed” and surely overall performance, I’ve found it (in my limited experience) to have a profound effect on how multiple subs couple either together or with themselves (in the case of one sub per-Ch), due to variation in room (boundaries-mediated) gain. I get incredible bang-for-the- I suspect the ceiling, in particular, being equally reflective of low frequency, helps. Most sub frequencies should be more vertical line array-like behavior under normal height ceilings (~12’ or less) unless you go by 1/2 or 1/4 wavelength rule-of-thumb. A sub as a point-source (vertically-speaking) seems converse to how wavefronts should work, at least in nearfield, no? [Vertical reflections-mediated] room gain in this way should be considerably skewed anywhere studs and drywall are used over a slab foundation - highly unequal boundaries in the vertical realm for many (most?) listening rooms. |
Just want to point out that the usual raison d’etre for line arrays in a home is to use pistons with much longer combined size than the wavelengths of the frequency they are reproducing. Please, buy as many subs as you can afford, but you are going to have a very tough time creating a line array that is 56’ long. My only point is that yes, I love line arrays, but I’d have a tough time imagining that I’d get the same benefits for the same reason with an array of subs against a wall in my house. Of course, more IS better. 😂 If you are willing and able to put in multiple subs, SWARM may be a better value overall. In my modest home, one sub is my absolute limit. |