Subwoofer speed is in the room, not the box

@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. 

mijostyn

8,010 posts

02-24-2024 at 08:48pm 

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Exactly, the horizontal array of subwoofers forms a horizontal line source. Who says a line source has to be vertical?

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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-buck-driver surface area due to all boundaries being 6” solid concrete, except the front wall which is basically floor-to-ceiling glass (behind softwood blinds) - so essentially, strong retention along all boundaries and minimal reflections from the front wall. Back wall is far behind listening area.

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.

I was surprised to see the REL recommendation on gain and crossover.  I was under the impression that most had the gain set too high.  I did.