quote: A 15" subwoofer with an ultra-light cone and a ridiculously huge magnet isn't a subwoofer any more..
are u saying thats what my jBL is? it plays 30hz quite nicely.
and it doesnt have cone resonance problems,ppl use them up to 1k
quote:well first of all please tell me what type, size, etc of the box your going to put this sub in to get a decent response in a vehicle because i'm curious??
Sure
175L 40hz Fb
quote: side note on power compression, since you keep comparing your driver to higher spl drivers you do realize that MOST higher end "spl" drivers will be suffering MAYBE a 3rd of the power compression yours does at the 500wrms level mark equating to an easy 2-3db gain
maybe so ur guessing,and hoping. a 1/3 ? have u measured it? cos theres certainly no specs around.
if u showed me measured examples,i would say - 'nice,ur spl sub only exhibits a few db power compression,thats great u chose a good one'
IF their power compression figures were appropriately the same at 1xrms figure,and 0.5x rms figure, then yes it would have less compression.
quote: heck a JL audio 15w3 suffers the same level of power compression as your sub with 400wrms more input...and this is far from a "high end spl driver"
oh good uve measured this 15w3 too?can u show me the figures and graphs.
so quit saying things and
if everyone beleived what other ppl said with no facts,ppl turn at at forums saying 'my mate said square ports have no puffing' like recently at sounddomain.
hmmm, links? pickup almost any magazine that does reviews on subs and you will find power compression levels in there, carsound has a rather old archieve of some subs, mobilesound...pretty easy to locate eh
and about running out of excursion, at tuning the excursion increases only slightly with more power.youl run out of power handling before anything else. ....yes and most people know that cone excursion goes way down at tuning..its not this area of the frequency range that i'm worried about...its the other 95% of it that your driver is way out of its x-max range in
for music ,yes its important,but ur 8db peaking box wont run music.so all that extra xmax isnt always useful.To use it u have to pump in lots of Dbs more power resulting in Not the linear gain u hope for. I don't know what 8db peaking box you are taking about....i did a flat box for your driver as well as the ed 15A and can do it for a brahma as well if you'd like
if XBL2 is what it says,then it should be slightly better.i would like a good comparison.
my jbl is still linear at 500watts(just) it has 23mm xmech,and its only 1mm over its xmax,(assuming winisd is really accurate) how is your driver still linear with 500wrms??? your x-max is 7.6mm which you exceed greatly, i don't understand what your driver,s PtP excursion has to do with linear throw, did you mean Xmech?? and it actually looks like your driver will exceed its Xmech in a 175L box at 43hz and wont go back down below it till about 90hz....that can't be good
Take my sub (03 RE hc 15) slap it in a 4.5cuft box tuned to 35hz and it has a very similar excursion path to the jbl in the 175l Box..however when your driver is past even its xmech specs mean will only be at 55% x-max...resulting in me only losing about 1db from BL compression compared to yours, still being linear compared to yours that is down to almost no BL...not to mention mine wont be trying to rip the spider off the frame
when a sub has higher xmax and higher power handling,one would expect it has WAY more spl,when infact it doesnt. [b] no, most people wouldn't because SPL has to many factors in it, however much less distortion...yes
some one mentioned 12db,and this isnt true. 12db Potential then these things called 'physics' kick in and ur true potential isnt realised,unless its optimised. correct, but there are gains no matter what, look up displacement changes online
for example,if i double the power into a same boxed tempest- it scores slightly higher than jbl,because the box peaks 8db..meaning its crap for SQ. and the xxx15 too,it peaks the same.u cud make it flat,but then it cant beat jbl.
but-its a cheap woofer designed on a budget [b] ...a $200-250 woofer isn't a cheap woofer in my mind
my point is-
my sub CAN play music while doing DECENT SPL
im not saying it will win spl comps,it cannot.
different purpose for it-but u can see how 97db efficiency + a matched amount of excursion so u can use near RMS rating or more,of power,is very effective.
also having resonance at 40hz doesnt hurt its ported box response in SPL and also results in higher efficiency.
can u not admit that the jbl2226 is a versatile piece of sub? this drive looks like it was designed for highly sensitively horn systems to get the most out of small amounts of power
in 280L sealed it doesnt deviated 2db and it works right up to 1k,so u can crossover ur JBL horn for ur HT system right there-2way system
quote:hmmm, links? pickup almost any magazine that does reviews on subs and you will find power compression levels in there, carsound has a rather old archieve of some subs, mobilesound...pretty easy to locate eh
i live in newzealand,these magazines are most definately not available
are any available online/?
quote: .its the other 95% of it that your driver is way out of its x-max range in
well i dont know what woofer ur using! mines fine.
are u running winisd?
quote: I don't know what 8db peaking box you are talking about....i did a flat box for your driver as well as the ed 15A and can do it for a brahma as well if you'd like
i made the tempest xxx15 and my jbl2226 the SAME box cos when ur doing SPL,u want maximum box for max peaking right? tuned the same..
ok il make them flat,and then show u SPL.
quote: however when your driver is past even its xmech specs mean will only be at 55% x-max...resulting in me only losing about 1db from BL compression compared to yours
i dont have BL compression factor,only Power compression.
if ur using 55% excursion then ul be getting into the power compression effect after a short time. is that with 500watt? so , can u run 1000watt linear?
quote: no, most people wouldn't because SPL has to many factors in it, however much less distortion...yes
but have you noticed how many SPL subs such as xxx15 thud ,causing crap sound. nonmusical thudding,underdamped, uncontrolled resonance..
is ur sub flat in that box?i dont have t/s specs as i cant open respl.com with this crap pc,the fancy stuff kils it.
quote: this drive looks like it was designed for highly sensitively horn systems to get the most out of small amounts of power
it could be ,but not low stuff. the basshorn rear chamber is too large,100L or so,for 30hz. however for a midbass bin,it would excel because its underhung and Already low distortion.
check the low distortion figures with 60watt on 280L sealed.
my point is-
my sub CAN play music while doing DECENT SPL
im not saying it will win spl comps,it cannot.
il make the other subs Flat response also,and il show u the SPL levels with equal power
posted
if u think about it-in a car u have a maximum volume,and u tune for maximum spl
but if u want SPL and SQ with the xxx15 u must choose-do i want flat and nice,or peaky for SPl
but with jBL its already got that efficiency. although it doesnt reach the 20s ,its raw efficiency makes up for that giving SPl where u need it-in the 40s
cabin gain will make up some 30s(to some degree)just like sealed boxes-but to a lesser degree.
posted
First thing I found under a Google search is this... JBL
Quoted from the website...
quote: That's a very efficient pro woofer with an FS of 40Hz. which is about an octave too high and and XMAX of only 7.62mm which is about half of what you should look for. The 15" Adire Audio Tempest driver I use with an FS of 19Hz. and DUMAX of 16.4mm would be a much better choice for a subwoofer driver. It would easily outperform the JBL 2226 and only costs $150. I'd guess the 2226 price is at least triple that amount. I strongly doubt that JBL's product literature recommends the 2226 for use as a home subwoofer driver.
The low distortion specs for the JBL have been misinterpreted -- they only apply to 100Hz. to 500Hz. which are well above subwoofer frequencies. Distortion at under 50Hz. is probably much higher (although output under 30Hz. is likely to be weak unless boosted a lot by cabin gain). Very few people could hear subwoofer harmonic distortion under 5% while listening to music -- often 10% distortion is required before most people would notice. That's one reason subwoofer maximum output tests often use a 10% harmonic distortion limit. Paying a lot more money for a pro woofer to reduce already inaudable harmonic distortion by a few percentage points may please the owner of the driver, but is probably not an audible improvement.
reducing harmonic distortion bhear v
-------------------- $20 Xtant 15's 9 cubic foot box at 45 hertz MTX 81000d at 1 ohm 144.76 decibels on Termlab Posts: 336 | From: Houston | Registered: Jun 2003
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The JBL would work fairly well for high tuned SPL since excursion is not high at resonant frequency.
But, if you put it in any other box, I don't see how its going to rival any other subs. In a sealed box, it will not have near enough excursion to produce decent output.
In a low-tuned ported, you will have nice output around resonant frequency, but its going to exceed it's linear excursion limit at most frequencies on either side of this.
Also, sensitivity is not linear....once again.
WinISD does not take that into account.
-------------------- $20 Xtant 15's 9 cubic foot box at 45 hertz MTX 81000d at 1 ohm 144.76 decibels on Termlab Posts: 336 | From: Houston | Registered: Jun 2003
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The JBL would work fairly well for high tuned SPL since excursion is not high at resonant frequency.
it can work there.
quote: But, if you put it in any other box, I don't see how its going to rival any other subs. In a sealed box, it will not have near enough excursion to produce decent output.
have u modeled it/ or are u quoting a person u dont know ,and have to trust-richard greenes word on that.i have talked to him several times on that forum about jbls woofers.
quote: In a low-tuned ported, you will have nice output around resonant frequency, but its going to exceed it's linear excursion limit at most frequencies on either side of this.
500watts just linear,and very high SPL my mate has 23db cabin gain, just before i modeled about 120db in winisd,143db.-minus power compression(if not a burp)6db. (notice no one takes into acount power compression when selecting SPL woofers.
quote: Also, sensitivity is not linear....once again.
i presume ur talking of SPL gains with increasing power. i have already addressed power compression in previous posts.and also stated how 'spl 'woofers do not show that spec.
quote: WinISD does not take that into account.
u cannot model non linear effects with a linear model.
quote: Paying a lot more money for a pro woofer to reduce already inaudable harmonic distortion by a few percentage points may please the owner of the driver, but is probably not an audible improvement.
oh sure distortion is very good,particurly how it makes the signal NOT what it was
therefore since distortion doesnt matter we should all look for the most highest distortion
why do u think ppl love well designed horn systems? because they PRESERVE the input signal and DO NOT distort
its called SOUND QUALITY and HI FIDELITY
if a woofer is low distortion in the normal range,then as u increase excursion,it will distort more,and at a 'normal 'excursion, this 'low distortion'woofer will distort less than- some woofer that has high distortion but we dont care because 10% is fine,that 10% will go up
have u see www.mfk-projects.com ? the 2nd and 3rd harmonics are often just a Few db below the fundamental
posted
all drivers suffer from BL compression, as soon as power is introduced the bl starts to drop...drivers like the XXX and brahma can keep a flater BL for much longer then most resulting in less distortion and better sensitivity, the power compression is not what you should be worring about...its the BL compression with your driver that would kill you on the sensitivity
when the driver gradually increases x-max and eventually exceeds it the BL really starts to drop
load up your driver in the 175 box..or any for that matter in winISD pro and use the cone excursion graph...look at the x-max from your sub...that is what i'm trying to get at
carsounds website has some reviews on woofers you can look at...all are really old but you can get an idea of power compression levels on different drivers, the average middle end drivers have about the same level as your sub(about 3.5-4db at 500wrms) then you look at drivers like the aw1508 and the jugg(i guess what you'd describe as a higher end driver)and they have about 1db of power compression at 750-1kwrms
posted
near? there is only one tiny point on that frequency chart where it isn't PAST x-max
Posts: 3421 | From: Owosso MI, USA | Registered: Apr 2001
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posted
HAs anybody EVER measured sensitivity? The ones that are usualy labeled by companies are TOO HIGH! Untill now only the Brahma did what it was declared...(i must say I live in Slovenia and we haven't tested many USA-made subs...) Look at the DLS SP15 then, buy it now(it has 99,9 dB declared senstivity-if you actually belive it)! IF A SUB HAS REAL SENSITIVITY AROUND 91 dB, you can be very happy with it!
-------------------- Team Audiox-165,2 dB(dBdrag E1-2) Posts: 184 | From: Slovenija | Registered: Feb 2003
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posted
It seems to me that the issue here got a tad out of line. As for the magnet's size, weight etc.., that means nothing in comparison to the GAUSS strength of the magnet, that's why there are different types of magnets out there, from Ferrite(most common) to Neodynium, and injection formed magnets. As for "hitting hard" that is more reliant on the cabinet design, and airspace to be filled. The most common problem with SPL vehicles that prevents their systems from attaining the results shown on their computer graphs is from "doubling",(when a speaker can't react fast enough to a signal, because it hasn't reached max. excursion from the last note) which is most always from improper box design, and application. As for relying on spec sheets, keep in mind that the specs for whatever you are looking at , wasn't tested in your car, with music, or with speakers connected. so unless test tones is what you like, I suggest you trust your ears (did you know that it would take $20Million dollars to have scientific equipment that will equate what your ear can do? you got 2 of them, and in stereo!
-------------------- E.C. Wuz here Posts: 1057 | From: Vancouver, British Columbia, Canada 'eh | Registered: May 1999
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> As for the magnet's size, weight etc.., that > means nothing in comparison to the GAUSS > strength of the magnet, that's why there are > different types of magnets out there, from > Ferrite(most common) to Neodynium, and > injection formed magnets.
No, thats not correct. The gauss strength is a measure of the magnetic flux at the measured point, essentially its a measure of the strength of the magnet. It doesn't indicate mechanical force though, something must interact with the magnetic field to generate force. BL is a measure that includes the voice coil interaction, so it describes motor strength rather than just magnet strength.
The different magnet materials have their different characteristics, such as curie temperature, strength vs size, costs, resistance to atmospheric changes, etc. All can achieve high strength levels though. It's just that materials like ceramic need more size to achieve the same flux levels as a more "powerful" material like neodymium. So the ceramic magnet will be bigger and heavier for the same gauss strength as something like neodymium or alnico.
> As for relying on spec sheets, keep in mind > that the specs for whatever you are looking > at , wasn't tested in your car, with music, or > with speakers connected. so unless test tones > is what you like, I suggest you trust your > ears (did you know that it would take > $20Million dollars to have scientific > equipment that will equate what your ear can > do? you got 2 of them, and in stereo!
Are you talking about the T/S parameters? If so I think its pretty widely accepted that its an accurate way to model the low end performance of a system. Design work requires just that - and its possible to simulate an entire system beforehand before the first piece of wood is cut. But I'd never use just my ears if I was looking for anything remotely good sounding.
Adrian
Posts: 2 | From: Australia | Registered: Oct 2003
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quote:Originally posted by kan3: near? there is only one tiny point on that frequency chart where it isn't PAST x-max
what xmax chart are you using? il show.
same power ,same box (for some sort of comparison )
notice how the jbl doesnt need the unmusical high peaking action to maintain SPL.
but ofcourse 600watt is the maxium rms rating of jbl,the xxx15 has 1.6kw rms,so in theory could get.3-5db more assuming it has very good Bl,Power compression.
quote: The most common problem with SPL vehicles that prevents their systems from attaining the results shown on their computer graphs is from "doubling",(when a speaker can't react fast enough to a signal, because it hasn't reached max. excursion from the last note)
what are you talking about.
'cant react' 'doesnt reach xmax'
you realise that a speaker follows the input voltage with its own characteristics such as-
delay-time when the speaker hasnt started moving overring-when the speaker has now reacted,but the resonant circuits cause the speaker to not stop moving..like a Qtc=1.0 or higher sealed box(for example) a highly boomy SPL ported box wil exhibit this characteristic.
it has a lack of damping at this port resonance ,and high output.
excursion will be higher also.
it isnt musical.perhaps this is what your talking about.
quote: It seems to me that the issue here got a tad out of line
if off topic discussion results,and the person has had their question answered,theres nothing wrong with that.
quote:Originally posted by shizzzon: well, let me say this-
Audiobahn has told me that we should only use subs with the highest efficiency rating such as their Immortals which the 15 is 97 Db with 2000w RMS.
Treo engineering has subs that they manufacturer where the efficiency rating is rated in between 85 - 90db which i have never used before but their magnets on these subs are outstanding, 500 to 870 OZ! That's what i am wondering.
According to a few programs i use to calculate all that stuff, it told me the treo engineering subs would do worse than these 1 subs i was looking at would-
1200w rms treo engineering subs with 700+ oz magnet would do 8 Db lower than a 900w rms sub that has only a 120 oz magnet. Both of these programs were lowering the treo cuz of efficiency but the Xmax of the treo vs the other 10 is 4.5x longer!, yet still 8 Db lower???
I also noticed if you change the xmax number in these programs that your SPL chart does not move!
That's a bad sign.
So the main thing is, how do you know you are buying a good sub or not?
In my opinion, efficiency specs are absolute crap and the worst possible indicator of performance that you could begin to use. Efficiency is rated differently by many manufacturers and is easily manipulated. In a real world install your efficiency is affected by the enclosure size and accoustic loading. In my hunble opinion, it is very bad advise to tell someone to use efficiency ratings to make a decision.
Now on a positive note, I have been very surprised by the Inhuman series of Audiobahn subwoofer. Please understand, I have been very openly negative in the past when discussing Audiobahn products. Maybe more negative then they have deserved. I did an install for a customer that brought us one of these subwoofers recently and we were all surprised by the output capability of this sub. Now I wouldn't go so far as to compare it to some of the true SPL subwoofers on the market because it hasn't proven itself yet. But it's the first Audiobahn product that I have spoken positively in a long time. It is good enough to make me re-consider their products from retail sales point of view. I would not call it an efficient subwoofer thou
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