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Break-in is done. T/S parameters stabilized after 85 hours. No change at all after 100 hours now. There really was a parameter change during the testing.

My conclusion is this; If the driver is not broken in -

Q is higher than spec.
Fs is higher than spec.
Vas is lower than spec.

I'm making a front plate for HD testing tonight, I'll post the results later. I'll try some other new driver and see if the results is consistent with these findings.
 

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Discussion Starter #64
interesting- T/S parameters took ~ 85 hours to stabilize. unless i am imagining things this corresponds with my noting different sound characteristics up until ~ 90 hours of use in my car.
 

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Hello guys, I bought one today, could you give us more data with your impressions and subwoofer box, please? avanti1960 what sort of equalization did you set up? I want to try the same box you did in my golf GTI, gonna make a false floor to put the new box.
Do you think the orientation of the subwoofer would help spatializing? Firing rearward or firing upward, or it doesn't matter?
 

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Hello guys, I bought one today, could you give us more data with your impressions and subwoofer box, please? avanti1960 what sort of equalization did you set up? I want to try the same box you did in my golf GTI, gonna make a false floor to put the new box.
Do you think the orientation of the subwoofer would help spatializing? Firing rearward or firing upward, or it doesn't matter?
All of this is exclusive to your car's unique cabin environment. Nothing is going to help you narrow down what works in your car other than what works in your car.
 

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Discussion Starter #67
Hello guys, I bought one today, could you give us more data with your impressions and subwoofer box, please? avanti1960 what sort of equalization did you set up? I want to try the same box you did in my golf GTI, gonna make a false floor to put the new box.
Do you think the orientation of the subwoofer would help spatializing? Firing rearward or firing upward, or it doesn't matter?
hi horuspeed, location of a sub can make a noticeable difference to the sound you hear in the driver's seat. i have had "portable" subs that i would move around and try to find the place that sounds the best. generally for my car the right rear corner was the best place, sub woofer facing away from the nearest wall or upward / downward (if there were feet on the enclosure).
for me it all came down to practicality- i wanted to get the sub out of the main cargo area and under the floor that covers the sub cargo area.
fortunately the sub cargo area in my vehicle gave me just enough room build a nice solid enclosure and of the appropriate volume for a sealed 12" sub.
my enclosure was 1.4 cuft net volume including some allowance for a lb. bat of polyfill. Dimensions 29 x 14 x 8.375 inches, sub firing upwards and located on the end of the enclosure for rigidity. the sound is fine despite not being in the best location in the vehicle.
you may have limited options trying to fit and position a sub enclosure in your vehicle and difficulty trying to find the best location until after you build it. focus on the enclosure design- make it rigid with lots of internal bracing. mine is as solid as a concrete block and i believe it made a positive difference how the sub sounds.
the only EQ I have is some reduction around 50 hz to smooth out a peak in the response. good luck!
 

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any idea of SPL numbers this can make?
One realistic way to look at this, is the overall volume that can be displaced (cone area times the stroke). The linear stroke is 12.5mm one way and the cone area is typical of a 12 inch subwoofer. Considering 12.5mm is pretty average, I guess the SPL is comparable to what's produced by an average 12 inch sub in a sealed box (e.g JL W3), but Scanspeak may fill the lowest bass better. The overall stroke distance is something like 1 inch each way, which can be considered pretty good, but beyond the xmax distance distortion will be rising. Realistically, for a bit more SPL, you may want to check out the Image Dynamics IDQv3. It's a good SQ subwoofer, which has 19mm of xmax, and costs about the same as Scanspeak or cheaper. My understanding though, the IDQ's distortion will rise rapidly beyond its xmax as its overall stroke is still something like 1 inch each way. So in the end, their SPL may be equal at the limit.
 

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any idea of SPL numbers this can make?
probably not exactly what you are looking for but the attached pic was the sub measured yesterday- no EQ, crossed at 20Hz 36db and 100Hz 24db.

500 watts of clean power, approximate 2/3 volume.

this was some loud bass and it was shaking the whole car- i thought i was in a space capsule re-entering the earth's atmosphere!
 

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any idea of SPL numbers this can make?
If you know the transfer function of your car it can be simulated somewhat accurate, assuming placement remains the same. Output is calculated from Xmax*Sd, this gives to the volume displacement.

Gonna post some tests I've done later.

Sent from my Samsung Galaxy 3 via Tapatalk.
 

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probably not exactly what you are looking for but the attached pic was the sub measured yesterday- no EQ, crossed at 20Hz 36db and 100Hz 24db.

500 watts of clean power, approximate 2/3 volume.

this was some loud bass and it was shaking the whole car- i thought i was in a space capsule re-entering the earth's atmosphere!
Wow, you do seem to have quite a larger peak than I do at about 40 Hz. I have a peak there but not 10db! I would say we do have some cabin gain going on there. Also, why did you put the 20 Hz cross on when looking at the response? I would think that could be why it looks like the response is tailing off. I know I noticed a difference when I had a subsonic on my Ultimo. I figured I have never heard it bottom before and it is in a sealed box so I killed the subsonic completely and am way happier for it. Just my 2c
 

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All right. First set of tests. My simulation of the box size and port length was off. My intended tuning frequency was between 30-31Hz, it ended up at 25-26Hz instead. Don't know why this happened really, but anyway - I'm sharing my tests before I modify the enclosure size.

These test was measured at 1m with a calibrated ECM8000 mic. Input voltage was 18-18.5V (avg). Above 35Hz, excursion was pretty high, I'd say around Xmax rating. I also provide measurements on tuning frequency, how it changes by adding dampening wool. Measurements done outside the car in a large room. Applications: RoomEQ 5 and DATS.

Notice the increased amount of distortion that coincides with box resonance /40Hz.

HD tests:

20Hz:


25Hz:


30Hz:


40Hz:


50Hz:


60Hz:
 

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Impedance sweeps, tuning frequency is slightly affected by adding wool. Efficiency is not affected very much.

Without wool (Fb ~28Hz):



50% added wool (27Hz):



100% added wool (27Hz):

PM sent for info on how DATS works.
 

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Discussion Starter #78
Wow, you do seem to have quite a larger peak than I do at about 40 Hz. I have a peak there but not 10db! I would say we do have some cabin gain going on there. Also, why did you put the 20 Hz cross on when looking at the response? I would think that could be why it looks like the response is tailing off. I know I noticed a difference when I had a subsonic on my Ultimo. I figured I have never heard it bottom before and it is in a sealed box so I killed the subsonic completely and am way happier for it. Just my 2c
the 50Hz peak is either cabin effect or a glitch in the RTA software / mic calibration or sound calibration. It shows up even when i am measuring the midrange / tweeters.

even though the enclosure is sealed i have been running with the subsonic on through the headunit as an HPF. It helped to tighten the sound of my JL sub and was noticeable. I also read where it conserves amp power by not using energy generated inaudible pulses- helping to divert the power to audible frequencies.

however after reading this i turned it off and it does seem to play a little deeper- I will have to measure on the RTA now to see if there is a difference, thanks.
 

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Discussion Starter #79
"Subsonic" filters are not very useful in sealed enclosures.
OK, thanks for the suggestion- although the filter helped with my sealed JL sub.

But having run the ScanSpeak sub with no sub or high pass filter all I can say is WOW! It took the lid off this speaker!
The bass notes are deeper and they sustain- / linger and taper off- in a very good way.
Impact is noticeably better- especially on kick drums- which sound as life like as any system I have heard.
It literally sounds like a new (and much better) sub- and still blends incredibly well. Unbelievable.
I will definitely RTA it this week-end and post a comparison - filter / no filter.
 

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"Subsonic" (weird naming that is, hence the " ") filters are basically simple highpass filters, sometimes tall order filters. The only thing they do is basically lowering amplitude on the frequencies below the set point. Depending on type of filter, rolloff might begin slightly above this frequency. As with any filter it affects phase and as a result transient response, note that this effect is practically inaudible in this case. These subsonic filters are normally used with vented enclosures and are placed like 10Hz below (Fb) to prevent unloading, since a sealed enclosure controls excursion infinitely low it's not needed. If you tune a vented enclosure in 20's or low 30's they are not needed either imo.

Here's a good read about filters:

Active Filters
 
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