Top notch speakers with their own sub

Jax2 writes:
>Hey Duke (or anyone else who cares to comment) - Is a flat response always necessarily an ideal target?

The goal is flat on-axis response with a gradual directivity increase (or decrease in total power response). Your ears take a few cycles to pick up low frequencies so total power response comes into play more there although there seems to be some time domain component with steady-state measurements being an incomplete approximation.

Floyd Toole and Sean Olive at the Harmann Group have done studies on this with blind listening and their computer controlled speaker mover. The preferences hold regardless of listeners preferred musical genre, country of origin, and experience/training in critical listening.

>What I've objected to in some other approaches is that you become very aware of the low end to where it becomes distracting. I don't know whether this is due to overemphasis, room nodes, or some other imbalance.

It's the room and speaker+listener placement. Peaks really over-whelm the music. Placement too close to boundaries increases the whole bass spectrum. In-phase bass signals in the music add +3dB to total power response at high frequencies but +6dB at low enough frequencies. The room has up to 12dB/octave of gain below its fundamental resonance.

Reducing modal problems and room/boundary gain does a lot for natural bass which is like music as opposed to some fast, slow, tubby, or thin approximation that's noticeable and distracting.

In re-reading this thread I may have given something of a wrong impression re: EQ vs distributed subs. I love the idea of distributed subs and wouldn't be at all surprised to eventually own a set. I might very well still utilize room analysis/EQ, but mainly to help optimize placement (room analysis) and fine tune for +/- 1db or so for the 1/2 octave above and below my chosen x-over frequency. I suppose that some additional PEq might prove beneficial if any little anomolies survive the placement excercise, but I suspect that it would be minimal.

Marty

PS Duke - is there pricing info on the Swarm and Planetarium systems? I didn't see any on your web site. Not that I'm thinking.....

Spatine writes:
>Discussion on sub equalization and placement going on today is precisely the reason I hesitate straying from the mainstream speaker establishment. Now I have more plausible theory as to why major speaker manufacturers don't want to package non-integrated subs with their main speakers for music listening just yet. The technology is not sufficiently developed.

The technology is _fine_. Existing implementations are audibly, measurably, and theoretically superior in real rooms. "audiophile" exposure to cheap one-note sub-woofers and poor integration have created marketing prejudice against separate woofer enclosures. Spousal acceptance of additional boxes is an issue especially when placement constraints are taken into account. Some products call for more technical setup procedures and measurements for the maker to tailor transfer functions.

Mainstream speakers sound like speakers not live music due to inherently flawed physics which are addressed in alternative designs. You'll end up with a much more natural sound, better decor match (at the fringes it's small companies with made to order products. Figured woods/veneers, inlays, and finishes can be mixed and matched), and spend less money (you're mostly paying for parts and a furniture maker's time).

Speakers like the B&W Nautilus Prestige (acoustically small drivers+baffles with damped transmission line enclosures) and RAAL Requisite Eternity (uniform horizontal polar response, and I'd guess that the vertical response matches up well around the cross-over frequencies) take some steps to get there, although tighter uniform dispersion interacts less with the room. Bass needs separate enclosures and/or dipoles. Room specific bass filter functions are a good idea.

> Secondly, the idea of having 4 sub is quite intrusive, one way to get into major fight with your wife.

All but one location can use smaller woofers (they don't have to extend below the room's fundamental resonance, so they're not really sub-woofers) in smaller enclosures. AFAIK Earl Geddes is using 6th order band-pass boxes which can be 6dB more efficient for a given cabinet size and low frequency cut-off than a sealed design. In theory they ring more than a sealed or 4th order ported design, but the room dominates time domain behavior. In theory they have more group delay, but you need cycles of audio to pick up bass. Generalizing from small "sub-woofers" sold to the mass-market with a strong resonance to substitute for real bass doesn't apply to good ported designs and shouldn't be applicable to 6th order ones.

Spatine,

Didn't your Preludes utilize the RABOS system (IIRC a bass EQ scheme)?. Since you asked for current technological implementations, the answers naturally tended toward sat/sub variations and, eventually, EQ. The separate sub idea allows more placement flexibility. Additional placement flexibility isn't going to hurt things, though it's not 100% guaranteed to help, I suppose. Similarly, multiple subs offer even more placement flexibility. In the end, choose the approach which best suits your needs, but -in your place- I wouldn't be so quick to dismiss the potential advantages represented by some of the ideas here.
At the very least, there's some good food for thought.

Good Luck

Marty

Marty, I do appreciate the discussion. We are not talking and about your intention, and RABOS is definitely an EQ scheme of sort. The differences here are that I already know RABOS works and have been praised as an oddity in light of too many things that don't work. All I am saying is that hearing you guys somewhat disagreeing among yourselves doesn't help me build confidence in the unknown any.

Now what I didn't tell you yet is that even a few tens of dollars is not to be wasted in my life. So an upgrade from the Prelude MTS has to be truly an upgrade. Sort of better kinda thing is money not well spent. Why do I have a sense that in order to have that sufficiently spectacular improvement, thus justification to spend money, the order of improvement would have to be something in the scale of say ... the Wilson Maxx. Otherwise I am better off to sit still. Regardless of outcome, I do appreciate everybody's pitching in.