Sub output: Is it the woofer size or the rated RMS

Stanwal

I didn't attack manufactures at all, I simply stated that the reason they build small subwoofers is marketing. (the wife part was half in jest, and half not). A lot of people want subwoofers, in this day of hometheater. And many of those people can't, or won't buy huge boxes, they want small...and for many reasons.

Manfactures cater to market demands...thats called marketing, in case you didn't know?

I also didn't mention money (although you seem high on that subject...what a snob), didn't mention your $3,000 subwoofers, didn't mention my system...or my subwoofers...you did all that.

I simply stated that your "cone linearity" statement was hogwash, and that the large drivers of old that you mentioned (and implied was the wrong direction), were a product of their time, and of that times technology.

Actually, the two huge drivers you used as examples, saw limited use....smaller 18", 15", 12" drivers were used in most designs as I recall it.

I fully understand that many manufactures make "very fine" small/med/large subwoofers for todays "market" needs....but they don't make the small subs, because they found out they were better than the large subs (although they probably are better than the large subs of years ago, given todays advanced technology).

I may be wrong, but I believe the Sunfire True Sub (I bought mine 2 months after they came on market)was the first "small" sub (12" cube). As Drew posted, it takes a lot of power to produce a FR response down to 16Hz in such a small enclosue (even though a 12" speaker is not "small").

Bob Carver designed the 2700w RMS amp to compensate for the small box. Was Carver motivated by market demand for a small sub? I think so and more power to him.

Sogood, it is strange to see me called a snob because I pointed out that not all subs that used small drivers were cheap. The idea that marketing was behind sub design implicitly assumes that it is money that drives the market. I will point out to you that Wilson has just replaced 2 18" drivers with ONE 12" in their latest sub, the Watchdog, which runs $10,000. Do you really thing that this is to make it more paltable to wives? The top REL sub, at the same price, uses 2 10" and is widely regarded , IN THE AUDIOPHILE COMMUNITY, as being possibly the best sub available. I am becoming aware that the HT community has a completely different set of priorities. When REL brought out the T series for HT use they were quite different from the S series designed for music reproduction. The T series has no real bass below 30hz ( as opposed to below 20hz for the bigger S series) and the lowest filter setting is 60hz. With my subs I start rolling them off at 22hz. The idea that cone linearity and speed are irrelevant can be instantly falsified by looking at the speaker compliment of large speakers. The new Snell Illusion , which is their best speaker, uses 2 10" magnesium cones and is specified to be -3db at 27hz. Do you think that when a company is trying to get $50,000 for a speaker they will not use the best possible driver combination? The Avalon Eidolon Diamonds , which are specified to be 1.5db down at 24hz use 2 11" woofers. They are about $34,000. Why do I mention money? Because I am a snob? No, it is to point out to you that at this price range the only consideration has to be performance. All of these are far out of my own price range, the $2600 I paid for the Duettas is my high water mark. Ah, you say, but these speakers are not subs; while smaller cones may have an advantage at the range these speakers operate in they do not at the low end. This assumes that there is some magic frequency at which physical law inverts itself and what was true at 100hz is no longer true at 50hz. Someone mentioned that smaller cones have no advantage in the range 20-80hz. If this were true why do the speakers mentioned above not use larger drivers? I have never heard anyone suggest that the B&W 800d needs subs, yet it uses 2 10" woofers. The less mass something has the quicker it can react. The smaller it is the more linear is the movement. this is simple physics. But, you say, speed in subs is unimportant/nonexistant. There we differ. The search for a sub that will mate with Quad electrostatics is over 30 years old. As they react much faster than cones most subs are hopelessly slow. But some do work; i.e. those with smaller drivers. It is also important in matching the main speakers, larger drivers have more momentum, they do not keep up as well as those 12" and below. All of this is regarded as self evident in the music reproduction community. The HT community obviously has different ideas. As I am not a member of the community, even though I do have a video system, I will refrain from deriding the ideas of its members if they will extend me the same courtesy,

>In any subwoofer output, how important is the Watt output versus the woofer size?

This also depends on the frequency range of interest.

The air you need to move quadruples with each octave decrease in frequency.

A driver with twice the area (say a 15" driver versus a 10" driver) can play 6dB louder. A longer stroke often goes with the larger diameter; if that doubled from 12 to 24mm you'd get a total of 12dB more output at low frequencies given enough amplifier power to use the excursion.

At higher frequencies you're limited by the power needed to overcome the stiffness provided by the air spring in the box + suspension; and at the highest frequencies you're limited by the power needed to accelerate the driver.

Stanwal

Some good points, so I'll keep this short:

Regarding Wilson:

(They have Thor's Hammer subwoofer?)...two 15's

Regarding Rel subs:(and in no way intended as a knock)

(Fine subs, but mostly over rated at Audiogon, and probably under rated, at most other forums? To be honest, there has never been a time as now, when so many good subwoofers are in the market, and we are very lucky. The "AUDIOPHILE COMMUNITY" is much larger than Audiogon, and much of the hype around Rel subs stays here, or at least your statement about them " being possibly the best sub available")

Regarding subs, or mains using multiple drivers:

(Multiple drivers give you more cubic inches, they move more air...see the Wilson Thor as an example that works along with your examples. Multi driver subwoofers were not in my subject line, they are a "whole nother subject"...although an interesting one that does bring some advantage, in some systems. My Apogee MiniGrand subwoofers use a pair of 8" drivers in each cabinet, and my VMPS subwoofers use a 12" and 15" driver in each cabinet, and a single VMPS subwoofer, uses only a 12" driver).

Like you, I'm not a hometheater guy...although I wouldn't be without one, and I do enjoy it now and then. My main music system is no longer using subwoofers (except when I play my little MiniGrands). My Duetta Signatures don't need subwoofers to keep up with the MiniGrands, and the large subwoofers rarely came into play, when I did use them for music in the past (so, I thought it a poor return on value)....and I moved them to the movie system where they get more work.

Regarding 20-80hz:

(Two octaves, the first one....one 15" has a clear advantage over one 10" driver in the 20-40hz range)....the winner?, the 15"

(The second octave, 40-80z?...I can't think of any reason, why a single 10" would have any advantage here either)....the winner?, probably an "equal result" at best.

This would seem to give the larger driver an edge?....a 50% win rate at least, while the smaller driver gets no clear win...0% win rate from 20-80hz.

At freq's above 70-80hz, and using a subwoofer at these higher freq's, your on to something, or at least your ear may be....as the small driver, begins to take any advantage away from the larger driver...no rocket science here.

Regarding hometheater subwoofers:

While they do make hometheater subwoofers (I like to call them "west coast subwoofers"....I'm sure you remember the west coast sound)...any "good" subwoofer can reproduce music and movies just fine.

Regarding Quad and subs:

Dipole bass and monopole bass, does not sound the same. In order to mate "monopole subs", with dipole speakers (at least in my experience, and to my ear)...you must use a filter slope that does not allow the sub, to be active above 40-50hz... 70hz max. (lower is always better)....it's not a speed thing at all. While subwoofers do need to be "linear" (except the west coast ones(-:)...they don't need to be fast? If any one driver is playing faster than another, it's playing a different freq. yes?

Any driver only needs to play, as fast as the freq. calls for, and no faster. Large drivers do have a speed limit, because of their size and weight, but 20-80hz is well within that limit for a 15" driver.

So, I'm going to end this short post, and say I agree with you 50% on subwoofers...and 100% on speaker choice...(-:

Dave