High quality subwoofer - which one?


I’ve owned my C4’s for about six months now, and they are excellent. But, you can’t ask a speaker to things it isn’t big enough to do. What that is, is to go FLAT to 20 Hz. The Vandersteen Quatro’s had built-in 250 watt class B powered subwoofers that are to die for once you hear them. The blemish on the Quatros, and it is a small one, was the slightly veiled lower midrange. The C4’s are absolutely seamless everywhere they go. The lowest bass can be fixed and most would probably say it’s not even necessary...until you hear a real sub system that is. Once you hear the effortlessly smooth low-end of a dedicated sub woofer you just can’t forget about it.

I started looking at subwoofers, and they are expensive, but relative to what this hobby’s cost(s) can be on some item(s), they are affordable. Well, ONE is affordable, anyway. I have three models that seem to all be nice products, and was curious what the feet on the street have used and your likes / dislikes. One model that I have not included needs an external hi-pass filter and I may be dismissing this model out of hand…and shouldn’t be and if you use this model, convince me.

I have a pretty large room (16’ wide x 40’ long x 8.5’ high (ceiling is split at 7.5’ and 9’)) so a bigger sub may be needed. Right now, I’m thinking ONE sub crossed-over pretty low. The C4’s do go pretty deep, but I probably agree that two would be “best” but expensive and the narrower room might make double placement hard. One is a snap, between the speakers away from the wall or near the right corner. I do not play “loud” (80-85 dB SPL average based on my radio shack SPL meter) but still like the smooth deep bass of a sub. Crazy loud isn’t the issue, but the sound quality is.

The choices are mind boggling in cost (JL Audio in mono or stereo) or mono (VELODYNE DD15+) verses stereo (SVS PB13 Ultra) set-ups at the same price. I have three options below to illustrate this.

The set-up that seems too expensive but outrageously good;
JL Audio Fathom f113 - $3600.00 / 13” / 2500 watts peak class D amplifier / sealed box.
But the sub needs a high-pass Cross-over like a Bryston 10B-STD @ $3,500.00

This is expensive compared to the SVS, but is it better than TWO SVS units?
Velodyne DD15 Plus - $4,000.00 / 15.0” / 1250 watt continuous class D amplifier / sealed box.

This seems like a good price but is the product good enough even if the price is? Use TWO of these in place of one DD15 Plus?
SVS PB13-Ultra - $2,000.00 / 13.5” / 1000 watts continuous class D / ported box.

So what have we done with subwoofers and why? This got real complicated real fast. Ported, vented, stereo at the same price as a mono sub ETC. The odds of auditioning these monsters are about zero as you hear the room. My room seems to be pretty good down low based on my Quatro set-up with powered subs. If a decision isn’t easy, I’m missing something…a lot of something’s it turns out.
rower30
I love to hear that the high-pass isn't needed but...

If I use the C4's full range and use the digital room processor function on the sub, WHAT pray tell smooths out the C4's room bass response? It seems like the mish-mash of the C4's and the sub would be unmanagable...and the advantage of limiting intermodulation distortion would be lost.

I thought that this was "AUDIO" and not an LFE web site. Yes, movies are fun, but I use a high-end AUDIO system for 2.1 (or will be once I get all this sorted out). I'm not being mean, but MUSIC is my main objective not sound effects.

I agree subs are probably HT biased, but the one's that are "supposed" to me music biased seems to me should offer a quality HP filter system as an option, or outboard option. Why KILL audio 2.1 or 2.2 buyers? OK sure, make it at least an option!

So I seem to be stuck on the Velodyne DD-18 Plus / JL Audio Fathom f113 or the Paradigm SUB1. The Velodyne has a High-Pass, so I can go either way with it. All are expensive, but they seem pretty good. The SUB1 probably is the best "active" EQ unit where the DD-18+ is pretty good if you use the manual EQ and learn to cut peaks and leave holes alone if a few dB of boost don't fill them.

Still, I'm learning. The REL seems like a good idea (witness Vandersteen's powered speaker internal sub solution)that I know works. I need to look into this product.
Rower,

WHAT pray tell smooths out the C4's room bass response?

The obvious answer is "nothing". Most folks who run the main speaker full-range simply fit the sub's response "under" the rolled off bass response of the main speaker and live with the same ragged bass FR they had before adding the sub - they just get more extension, "air", etc. The point of this approach is to leave the main speakers' response intact. I think that this is rarely the best idea, but many others here disagree.

In any event, manual adjustment of the subwoofer's FR via parametric EQ (Velodyne DD) will let you really customize the fit as you "snug up" the top of the sub's output to the bottom of the mains'. I have run the Carver Cinema Ribbon Monitor (which have very little response below 100hz in-room) full range with DRC subs and gotten pretty good results. (Obviously, your C4 is a somewhat different animal than the CRM.)

But there is another approach, albeit one that is not ideal for a speaker that has extended bass response: You simply overlap the the sub and the main speaker up to a desired x-over frequency.

If you do want to try this approach with your C4, you could (depending on the DRC solution you choose) face different issues:

Full range DRC (ala Audyssey in an AVR) will smooth both sub and main until the "hand-off" is smooth. There should be no issue there.

Sub specific DRC (ala Velodyne) will allow you to attempt to manually "mold" the subs' response around the C4's output in the bottom octaves. That is, during set-up, you will see a video display of the summed bass response of the C4 run full range and the subwoofer. You adjust the sub via a combination of master sub volume level, placement, phase and (perhaps a touch of) parametric EQ such that you get enough subwoofer output to smooth all meaningful bass nulls. You then EQ the peaks via parametric attenuation until you have the smoothest possible overall FR below the sub's high cut frequency.

I can't swear that this approach will work well in any given room with any given sub/main combo, but it might work with some combos in some rooms. I'd recommend it only for those who REALLY don't want to interrupt the main signal path.

As I've indicated above, I definitely prefer to low cut the mains - but I described this "pure path" alternative to illustrate that you might be able to use DRC for the subwoofer without "corrupting" the sacred source->pre->power-> main chain. Not the way that I'd do it, but you could try.

Marty

As to optional high cut units, it sounds good, but you'd have to build a workable business case.
The Vandersteen 2Wq subs come with a high-pass filter.....which IMHO......makes a huge difference to the headroom available for the main speakers.
They have three 8" woofers per sub driven by its own 300 watt amp.
The passive W2 high pass filter is good.....but the active W5 is just better (and able to be adjusted for impedance matching).
Two of these subs can be made to blend seamlessly into most rooms and as they are sealed (rather than ported) boxes.....the bass is tight, fast and tuneful.
I have also had success with a single REL (older Q150e). It really loads my room up nicely and has lots of adjustment/tuning options. At this point I would never NOT have one.