One "big" woofer or four "small"?

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dirkwright

dirkwright

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Joined 2011
mdocod said:
4x6.5" woofers will have over 500cm^2 of Sd in most cases.

1x10" woofer will have around or under ~350cm^2 of Sd.

I don't think they can be compared very fairly.

A single 12" woofer is a much better comparison, as they tend to have ~500cm^2 Sd.

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If the question really is 1x10" vs 4x6.5", Assuming typical average characteristics, I would lean towards the 4x6.5" for reasons of efficiency. However; If we go with the fair comparison of a 12" driver. I would lean towards the 12" unless I needed higher frequency reproduction from it.
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I think he was talking about 1 10" vs 2 6.5" per side.
 
Inductor

Inductor

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Joined 2006
tinitus said:
... you cannot 'isolate' a certain sound' aspect, without compromising other areas
and you may not like those 'compromises', or didnt expect them

its a bit like when they say, know your 'enemy'
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Wise info that the op may not think about now.
planet10 said:
One can do a whole lot of generalization, selection of real drivers could well change things.

In general a 10" will go lower giving deeper bass, 6s will extend higher and likely be easier to integrate with what comes above.

Personally i like to use pairs in push-push so as to get active vibration cancelation, and reduce the load going into the box.
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Dave, would you mind to give an example of the box you are talking about for better visualization of the mechanics involved.
planet10 said:
... Push-pull also uses 2 opposed woofers, but is harder to mechanically. It does indeed reduce 2nd order distortion but at the expense of 3rd order (but only if you are using "cheap" woofers out of their linear range. If the balance is tipped such that 3rd is larger than 2nd then it likely willsound worse.

dave
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Can you give a broad example (pic)...
Dave I would suggest a new thread, for better handling of this subject by us/members. I have been thinking about this the last couple of days.:)
 
planet10

planet10

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Inductor said:
would you mind to give an example of the box you are talking about for better visualization of the mechanics involved.
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An early illustration of an all out assault on the idea, using a woofer specifically designed to make it possible.

toobz woofer

pushpushPR2.gif


More practical examples can be seen in many of my FR bipole drawings, microTower and Thirlmere-R are 2 good examples.

microTowersx2.gif


(the 2nd set are Castle versions and don't take advantage of the push-push)

KEF were the 1st (that i know of) to introduce push-push with one of their 104s (?) -- 2 8' in a bandpass box and a connecting rod between the drivers. I had been introduced to the idea before this, but didn't take advantage until i started building subs. It has been used more and more often (by a number of vendors), and the latest incarnation is the KEF blade.

Anytime i can, i use this technic, particularily in woofers where the most can be gained -- almost for free it gives you the opportunity to remove, say, 90% of the mechanically transmitted load into the box. allowing for an easier to build, lighter box with a lower noise floor (and one that doesn't walk across the floor).

dave
 
AllenB

AllenB

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I've heard good things about these outside this thread although I haven't pursued it...yet. Dave, how would you rate (in order of importance or magnitude of the issue considering a typical high crossed sub or low crossed woofer, and possibly considering using a lighter box as has been suggested).... dealing with the three issues...mechanical vibration as in box walking, even order harmonic cancellation, and standard panel vibrations?
 
AllenB

AllenB

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planet10 said:
cancelling even order HD is not that important (Geddes)
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Thanks. Yes, I was trying to reconcile this looking at your diagram while wondering about the sound of SETs.

and if done (ie a push-pull pair) may increase 3rd over 2nd which is not the best scenerio.
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and this reminds me of that scan-speak woofer motor. Very clean but has you reaching for that SET again ;)
 
weltersys

weltersys

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Joined 2008
sumaudioguy said:
6.5" are not woofers, that is a midrange.
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Back when multi-cell horns like in your avatar were first created, your statement held some degree of truth.

Now there are 6.5" (and smaller) drivers with adequate excursion capability and low Fs that can put out far more low frequency than many 15" drivers of that era.

Cone diameter does not determine frequency response.
 
Pano

Pano

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weltersys said:
Now there are 6.5" (and smaller) drivers with adequate excursion capability and low Fs that can put out far more low frequency than many 15" drivers of that era.
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Sure, and with plenty of distortion at no added cost! I have owned a few 6.5" and 8" "subs." They are cute and do very well at moderate levels. Just don't ask them to play loud AND clean.
 
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