expensive VS cheaper subs....

[SkinnyBoy]

whats the diff??? I mean, say a $100 subwoofer is 100watts rms, and 91db efficient, vs a $200 subwoofer thats 200watts rms, and 88db efficient? I know you may need a larger box for the higher efficient sub to get the same response, but... welll.... so what?

I mean, the CVR12 (12inch Kicker Comp VR) has an efficiency of 86.4dB and power handling of "400watts rms" not sure on the price however, but how is that any better than a 12inch Venom subwoofer, which is 180watts rms, and almost 88dB efficient? (not a very good example I know)

[SkinnyBoy]

a better example....

two 15inch ReSponse subs with 300watts each, 200litre box tuned to 20Hz is almost as good as a single 15inch Brahma, with twice the power, in the same box... except, the ReSponse subs cost about $AU600 and the brahma will set you back twice this..... and yet, car audio people tend to always diss da cheaper brands...

[mikee12345]

at low levels the sound will be similar.

At high levels
Power compression
BL compression
Distortions-nonlinear and linear.
Cms nonlinearity ,cone resonance..

http://www.klippel.de/pubs/default.asp

Thats why i bought a jbl2226 not a tempest

[tktran]

Sometimes price has little to do with anything other than the ability of the retailer to mark up the units to whatever they think is appropriate.

Consider looking at all T/S data to determine suitability of driver for intended use.

Power handling and efficiency is important, but all it suggests is how loud (potentially) it can go...

[cowanrg]

the easiest examples i can think of are comparing full range speakers to subs... ie - comparing the bass from a REALLY big speaker that's passive with a subwoofer. the integration of the bass from the speaker is almost always better. it just sounds natural where subs tend to sound more separate. a good sub will sound (should sound) much more integrated, like its supposed to be there...

another example is the ability for bass to be very natural or to come from unexpected places. for instance, piano has very subtle bass that is sometimes hard to really accurately produce. same with a stand-up bass or cello or something. they have deep rich bass, but most cheap subs will make it sound like boomy rap music.

[GRollins]

I've said it before, and I'll say it again...the numbers:
A) Won't tell the whole story
B) Can't tell the whole story
C) Are likely lies made up by the market guys, anyway
My favorite example is the Shiva/Titanic class of drivers, since they're so popular. If you enter the T-S specs into a simulation program you'll get this really nifty looking plot that shows flat from 200 or so down to about 15-25 Hz. Makes you want to get out your checkbook, right? Wrong.
Build the sub.
Measure it.
Holy smokes, the reality isn't anything remotely like the simulation. What you find is that the things have a broad peak around 80-100 Hz or so, then a 6 dB/oct rolloff on the low end. This results in the 20 Hz response being something like 15 dB down from the peak.
Don't argue with me until you've actually built one and measured it.
If they don't show real plots made from real drivers in real cabinets don't trust 'em.
As an aside, this shows the weakness of the whole T-S approach. Not that we have anything better at present, but T-S isn't the be-all, end-all that some would have you believe.
Incidentally, there's much more to it than efficiency vs. price.

Grey

[Hybrid fourdoor]

Heres a question, more about sensitivity though, but since were comparing woofers.

How does sensitivity (spl/1W) compare to excusion (Xmax)? I mean if two 12" speakers have one watt going into them and one is playing at 92db and the the other is playing at 89db, is there much difference in the amount of excursion? Or is this a matter of efficiency? Like 1 watt "should" produce a certain SPL for a given surface area (say a 12" driver should produce 100db at 1W), but due to driver inefficiencies, they deliver less.

So lets say you have a PA woofer that has a sensitivity of 94db, but only has a Xmax of 6mm and one of these "uber" woofers with like 18mm of Xmax, but a sensitivity of 85db. The heavy duty woofer would need like 8 watts to reach 95db, but once there at 94db would the heavy woofer have alot more excursion movement than the PA woofer?

It just seems that a speaker can be more efficient, but to be louder you have to move more air, which simply requires more raw movement. Of which I can understand a 15" driver being louder than a 8" due to more surface area (bore X stroke = displacement)

[richie00boy]

Grey,

I'm intrugued by your findings. Were the measurements you took in anechoic or outdoors, i.e. in the middle of a field, conditions? Is it possible some room effects were happening if not?

Regards

[sreten]

Originally posted by Hybrid fourdoor
Heres a question, more about sensitivity though, but since were comparing woofers.

How does sensitivity (spl/1W) compare to excusion (Xmax)? It just seems that a speaker can be more efficient, but to be louder you have to move more air, which simply requires more raw movement. Of which I can understand a 15" driver being louder than a 8" due to more surface area (bore X stroke = displacement)

Hmmm.......

Excursion at any given SPL and frequency is identical
for the same size drivers in the bass (pistonic) range.

High sensitivity PA drivers are capable of producing very
high levels in the range where basically excursion is not
a concern.

Excursion quadruples for every octave you go lower
so it rapidly becomes a concern for low bass capability.

Maximum low bass levels are determined by excursion.
Sensistivity determines how much power is needed to
reach that excursion, and basically the lower the sensitivity
the more power you need but also the smaller the box
you can achieve your bass alignment.

If you compare different drivers in ~ the same size box it
rapidly becomes apparent high sensitivity has no advantage
when it comes to low bass levels - low bass levels are very
similar. So it makes sense to reduce sensitivity by making
the coil longer, i.e. more excursion for a subwoofer.

sreten.

[Jay]

I'm 100% agree with cowanrg based on experience. Good quality bookshelf is relatively cheap, but it is expensive to find a sub that match the bookshelf. Bad integration, delayed bass, all lead to a tiring sound. I suppose we hear music for enjoyment not for impressing neighbours with the bass.