Try to beat this 10" and don't ask silly questions. (And) Prove it!
Note: this in someway relates to "what's the best loudspeaker driver" question that many ask... good question, there's always a better one/application.
hi Rui, excellent response for a 10 inch, the problem is the low 84.6dB... there is always a problem.
Just do the Math, it will clear many doubts.
I have...many times
surely, if it's 20hz you want ... hard to do with a PRO woofer
but -3db at 20hz ? ... I wouldn't
suggestion, better try -6db/25hz instead
closed box, ofcourse
I think you can do that with a 90db SB Acoustics woofer
it will still be 85db at 25hz
Hoffmann's Iron Law: Loud, Low or Small, pick two.
With power available (new) at less than 25 cents per watt, (compared with well over a dollar a watt when the dollar was worth more than double what it is today) low sensitivity is not much of a problem.
If you want high sensitivity at very low frequencies with small diameter cones, horn load them in a large enclosure.
I'm not Rui, maybe you are confusing me with another member from same country (Portugal). He, he...
""Low 84.6dB"", as tinitus said, that's not bad (go read), and pay some attention to what he says and to the roll-off in the low frequencies in measurements and simulations of the big drivers like the 15's" and some of them you need to model them in the big theater/cinema boxes of 300L and plus that it's kind of awkward in your living room HT. Also notice that the Sub 12Pi by Wayne Parham, one of the best in the world has 2x12" and not a 15" or two (or a 18" for that matter).
Also in post #8 sreten put it in very simple terms and easy to understand.
You can not go low (infrasound) with a big driver but you can duplicate SPL (+3/+6dB) with double (10") drivers. You can also make isobarics and push-pulls or horns as was said before - ""horn load them in a large enclosure."", by weltersys on post #44.
And I don't take very serious (or lightly) what others say, that's their experience, just what you need, in your system and what your objectives are. Maybe we agree in something or everything but hey, I'm sorry, I just love to cheat on Hoffmann's Iron Law.
would like to add
if using 'ordinary' PRO woofer with adequate low Fs, just moderate EQ might do
and you can leave out the lower hifi woofer
on the other hand
adding the low Fs hifi woofer gives the opportunity to use a smaller PRO midwoofer with higher Fs
simpler and cheaper semi-pro driver might be ok for this
if using 'ordinary' PRO woofer with adequate low Fs, just moderate EQ might do
and you can leave out the lower hifi woofer
on the other hand
adding the low Fs hifi woofer gives the opportunity to use a smaller PRO midwoofer with higher Fs
simpler and cheaper semi-pro driver might be ok for this
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Is it the Altec 416-8C in a "vertical" 210 model cabinet?OK, nice satellites, but why no pictures of the woofers?
( ...in the original finish "utility gray".)
ok, question variation time.
You are blinded, or the speakers cannot be seen. What you DO know or can see are the two Fr of the bass. They are identical, and neither is driven past it's limit, ie they are level matched and neither is stressed.
So the box build is whatever is required for each situation with the appropriate driver and they have identical Fr's down to 25 hz say. Whatever power needed is there yada yada. Everything else is constant, down to the same in room response, same distortion figures, everything.
One is a ten, the other is an eighteen.
Does the bass sound the same?
You are blinded, or the speakers cannot be seen. What you DO know or can see are the two Fr of the bass. They are identical, and neither is driven past it's limit, ie they are level matched and neither is stressed.
So the box build is whatever is required for each situation with the appropriate driver and they have identical Fr's down to 25 hz say. Whatever power needed is there yada yada. Everything else is constant, down to the same in room response, same distortion figures, everything.
One is a ten, the other is an eighteen.
Does the bass sound the same?
Adding two 10" in a moderate sized box of 30L/50L gives the opportunity to crossover to a smaller 6" or 8" pro midwoofer with higher Fs... at around 90/95dB, flying on top of your head or floorstanding in front of you in your living room or in a disco/cafe/bar PA. You are just reading my mind...
Westlake Audio BBSM-10‚ÌŽd—l ƒEƒGƒXƒgƒŒƒCƒNƒI�[ƒfƒBƒI (pic)
http://www.gyraf.dk/schematics/Westlake BBSM-10.pdf
http://keycorner.org/pub/midi/Westlake-ProBroch.pdf (pic)
Westlake Audio BBSM-10VNF — Reviews and News from Audioholics (pic)
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That's not a problem. Actually it's very good, because that's one of the best drivers in the world, until another one it's made... and you compare that, if you like, since you are the one comparing a 10" vs. a 15" to start with,
A JBL 2242H (18") and, lo and behold in a horn loaded sub (JBL ASH-6118WH Horn-Loaded Subwoofer). (pic)
This picture from JBL (1x driver in 2 Pi space) showing ~85dB's is very similar in SPL to the simulation of the 10" woofer I presented in post #37 (from the point of view of the lower frequency roll-of). So where is the difference? The difference is in the upper frequencies and sometimes max. power between different drivers, nothing else.
http://www.diyaudio.com/forums/subwoofers/229349-sub-project-pa-help-needed.html#post3357260
If you want to make more comparisons you can pick the Eminence Lab12 used in the most/best SUBS in the world (like the 12π Basshorn Subwoofer by Pi Speakers) and it's only 89.2 (Sensitivity) from the spec sheet (and in a simulation was calculated as a 85.7 dB/2.83V/m for 2 Pi space/loudspeaker or 89.9 dB/2.83V/m for 2 Pi space in a baffle/"free field") or for that matter with my recent post for a ~140 L (BR) enclosure of the Stereo Integrity HT 15" Subwoofer here.
And after all this is very similar to the picture presented here by tinitus in post #50.
It is a natural characteristic of almost all the the drivers and in this case I don't see any difference besides the quality of the concept and that of the designer.
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The 10" has to work harder with bigger extrusion to make the same SPL as the 18".
This will cause more distortion with the 10". The cone of the 18" is bigger and maybe less stiff so that can cause thd to.
There are many mechanical differences that cause the colouration of sound.
If a 10"doesn't distort and the 18" also then they will not sound different at low frequency.
At high frequency the 18" will beam earlier so that can cause differences in that area.
So differences by THD and Dispersion pattern.
Then in the real world you get differences by linear distortion. Also the baffle plays a roll there.
Hi helmuth.
Was beginning to think my questions were of no interest to anybody else!
Ok, well I tried to cover your first point by limiting the spl of the test so that the 'lesser capable' driver is NOT distorting. Did not want that to the the thing under test.
IF you are saying that the smaller driver will always be distorting more (in some audible way) then the answer to the thread's question hos to be no, a smaller driver can never give you the same bass as a bigger.
Well mechanical differences could work both ways, maybe a better constructed smaller driver is better than a poorly constructed larger driver.
Also forget beaming as such, they are passed too low for that to be a factor (if that is possible). In other words I have constructed the thought experiment to try and only test the one thing.
Actually, I missed it the first time I read it, see it now replying.
If a 10"doesn't distort and the 18" also then they will not sound different at low frequency.
Thanks for the answer. (just as an aside, some of your points actually show that the smaller in most (?) cannot give you the same bass. Just turn it up a notch and get to the point where the ten is distorting and the 18 is not, well there is your point where the ten can no longer give you the same bass.)
Anyway, I gotta say I can't quite accept your point as true. I have NO idea technically why, I mean it seems reasonable 'they both have the same in room FR so they sound the same' (all other confounding factors like distortion being excluded).
In my 'group' I was by far the first to have something different than what you normally find 'in hi fi land'. We have all heard a lot of systems in our times seein as how we are into hi fi. Many with what is considered 'very good bass'.
But here was me, the first to come along with 18 woofers. You simply do not see that in (commercial at least) speakers.
Anyway, every one who heard it were 'shocked' at the bass. I mean it does other stuff very well (so it annoyed me in some ways) that the only thing people commented on in wonder was the bass. (haha, I go 'yeah, great bass but what about the imaging?' They say, man, that bass! I go 'yeah, great bass but what about that amazingly huge soundstage?' and they go, 'man, that bass'. I say 'look, shut up about the fvcking bass and tell me what you think about the dynamics' haha
)Now these are pro driver 18's, so they don't go low at all. I forced them with eq and power, the best they do is 35 in the room tbh. (since added subs but that is another question) And they are eq'd flat in the bass (smooth)
So, we are not talking extra extension that no-one has heard before (ie most/any other system with 'normal bass drivers' can match 35 in room.) The comparison is in the same area as any other system they had heard, bass (as opposed to sub bass)
The obvious explanation is simply the size of the woofer covering the same FR. And it IS easily heard as being completely different to any other bass you have heard. There is 'just that something about it'.
I don't know what that something is, hence my question. It ain't FR tho!
Maybe you are right, and all it comes down to is lower distortion?
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