Menu
Forum
General Car Audio
Subwoofers
Speakers
Amplifiers
Head Units
Car Audio Build Logs
Wiring, Electrical and Installation
Enclosure Design & Construction
Car Audio Classifieds
Home Audio
Off-topic Discussion
The Lounge
What's new
Search forums
Gallery
New media
New comments
Search media
Members
Registered members
Current visitors
Classifieds Member Feedback
SHOP
Shop Head Units
Shop Amplifiers
Shop Speakers
Shop Subwoofers
Shop eBay Car Audio
Log in / Register
Forum
Search
Search titles and first posts only
Search titles only
Search titles and first posts only
Search titles only
Log in / Join
What’s new
Search
Search titles and first posts only
Search titles only
Search titles and first posts only
Search titles only
General Car Audio
Subwoofers
Speakers
Amplifiers
Head Units
Car Audio Build Logs
Wiring, Electrical and Installation
Enclosure Design & Construction
Car Audio Classifieds
Home Audio
Off-topic Discussion
The Lounge
What's new
Search forums
Menu
Reply to thread
Forum
Car Audio Discussion
Subwoofers
CA&E 10 best subs
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
<blockquote data-quote="Remotia" data-source="post: 2150590" data-attributes="member: 568127"><p>That 12" critical mass driver in detail:</p><p></p><p></p><p>I saw the Bl curve and it’s respectable but not "linear" per say up to 36mm, it a typical 70% Bl around that number, not bad at all, but does that little 7” suspension even permit that kind of excursion? My doubts are in full effect. I have never seen an 8” spider pull past 3” p2p even with large roles with a very linear compliance past that point. Smaller 7” with give you great alignment, but there is no way it will hit 4”p2p without something breaking unless I’m missing something?</p><p></p><p>Dual gap design helps Bl linearity, but that high Q and a Vas of 50l tells me its very under motored even for neo and this driver will not work well in a ported box and my intuition is that 1.2 cubic feet sealed is far too small</p><p></p><p>The typical Enhanced Q alignment reveals 1.5 cubic feet and the Butterworth (deeper bass) yields a box size that is 29.7 cubic feet and I could not even get the Bessel to work. (these are all sealed boxes btw) There is no right or wrong box, but forget about deep bass with this driver in a small sealed box because its undermotored, low Bl and high Q. A compromise for the linear Bl if you will.</p><p></p><p>I used my pieced together T/S parameters below, they may be wrong, but are probably pretty close to the real deal because the Vas, Q and Fs and DCR are listed, we can reverse calculate the Bl product at a whopping 11 Tm. This is about on spec for a linear(esq.) motor such as this dual gap design.</p><p></p><p>Sensitivity: 96.7 db (2.83V / 1m) (coils in parallel) is actually ~10.6 watts.</p><p></p><p>Real SPL is closer to 84 dB.. Right on par with most modest 12" size subs and bested by a lot of high end drivers: Again $2000!?</p><p></p><p>Lastly, a 3" 4-layer underhung coil is not going to come anywhere close to 2500 watts true RMS. 500-600 true sustained RMS is probably closer, but I need to know the winding height first, but under hung wont be very high. Most high thermal overhung 3” coils should outgun it for power handling.</p><p></p><p>My best guess for piecing back together the T/S based on that info up there are this:</p><p></p><p>Sd 0.049 m^2 (close guess)</p><p></p><p>Bl 11Tm (reverse calculated based on Q and vas and the DCR)</p><p></p><p>Cms 139 (quoted)</p><p></p><p>Vas 47 (reverse calculated based on vas and Sd)</p><p></p><p>Mms 182 (reverse calculated based on vas and fs)</p><p></p><p>Fs 31 (quoted)</p><p></p><p>Qms 10 (total guess, this doest matter too much)</p><p></p><p>Qts (0.88) (reverse calculated based on Qms guess and Qts)</p><p></p><p>Qes(0.81) (quoted)</p><p></p><p>Revc (3 ohms) (quoted)</p><p></p><p>SPL @ 1 watt 84.1dB</p><p></p><p>This is not terribly impressive for this price ladies and gents. Granted the guy who reviewed it liked it, I’m sure the sticker price swayed some of that review as it always tends to do, but I’m sure that dual gap with the more than average linear Bl made it sound good above all those non-linear designs he tested it against. Many of those drivers should never have been compared to one another. This is a good example of why linear Bl is very important and we also strive for that, but beyond that, I’m clueless why its 2k.</p><p></p><p>Now time for the credit:</p><p></p><p>They used a Klippel analyzer, That is very a very respectable way to measure the driver…</p><p></p><p>Now time for my gripe:</p><p></p><p>WHERE IS THE KLIPPEL REPORT!??</p><p></p><p>I have rarely agreed with audio reviews, but at least we have em!</p></blockquote><p></p>
[QUOTE="Remotia, post: 2150590, member: 568127"] That 12" critical mass driver in detail: I saw the Bl curve and it’s respectable but not "linear" per say up to 36mm, it a typical 70% Bl around that number, not bad at all, but does that little 7” suspension even permit that kind of excursion? My doubts are in full effect. I have never seen an 8” spider pull past 3” p2p even with large roles with a very linear compliance past that point. Smaller 7” with give you great alignment, but there is no way it will hit 4”p2p without something breaking unless I’m missing something? Dual gap design helps Bl linearity, but that high Q and a Vas of 50l tells me its very under motored even for neo and this driver will not work well in a ported box and my intuition is that 1.2 cubic feet sealed is far too small The typical Enhanced Q alignment reveals 1.5 cubic feet and the Butterworth (deeper bass) yields a box size that is 29.7 cubic feet and I could not even get the Bessel to work. (these are all sealed boxes btw) There is no right or wrong box, but forget about deep bass with this driver in a small sealed box because its undermotored, low Bl and high Q. A compromise for the linear Bl if you will. I used my pieced together T/S parameters below, they may be wrong, but are probably pretty close to the real deal because the Vas, Q and Fs and DCR are listed, we can reverse calculate the Bl product at a whopping 11 Tm. This is about on spec for a linear(esq.) motor such as this dual gap design. Sensitivity: 96.7 db (2.83V / 1m) (coils in parallel) is actually ~10.6 watts. Real SPL is closer to 84 dB.. Right on par with most modest 12" size subs and bested by a lot of high end drivers: Again $2000!? Lastly, a 3" 4-layer underhung coil is not going to come anywhere close to 2500 watts true RMS. 500-600 true sustained RMS is probably closer, but I need to know the winding height first, but under hung wont be very high. Most high thermal overhung 3” coils should outgun it for power handling. My best guess for piecing back together the T/S based on that info up there are this: Sd 0.049 m^2 (close guess) Bl 11Tm (reverse calculated based on Q and vas and the DCR) Cms 139 (quoted) Vas 47 (reverse calculated based on vas and Sd) Mms 182 (reverse calculated based on vas and fs) Fs 31 (quoted) Qms 10 (total guess, this doest matter too much) Qts (0.88) (reverse calculated based on Qms guess and Qts) Qes(0.81) (quoted) Revc (3 ohms) (quoted) SPL @ 1 watt 84.1dB This is not terribly impressive for this price ladies and gents. Granted the guy who reviewed it liked it, I’m sure the sticker price swayed some of that review as it always tends to do, but I’m sure that dual gap with the more than average linear Bl made it sound good above all those non-linear designs he tested it against. Many of those drivers should never have been compared to one another. This is a good example of why linear Bl is very important and we also strive for that, but beyond that, I’m clueless why its 2k. Now time for the credit: They used a Klippel analyzer, That is very a very respectable way to measure the driver… Now time for my gripe: WHERE IS THE KLIPPEL REPORT!?? I have rarely agreed with audio reviews, but at least we have em! [/QUOTE]
Insert quotes…
Verification
Post reply
Forum
Car Audio Discussion
Subwoofers
CA&E 10 best subs
Top
Menu
What's new
Forum list
