Attn : Blue LEDz

[JProtege]

Hey man,

I know you've done it. You hit something like 150db with a 10" brahma. I don't need an essay, but how did you do it???

[blue LEDz]

147.2 dB's to be precise, on a term lab mic based system that was freshly calibrated.

the sub was a 10" brahma mark I powered by a power acoustik A3000DB.

the enclosure was a 6th order bandpass. the front chamber was 1.5 cu ft tuned to 54 hz and the rear chamber was 1.25 cu ft tuned to 23 hz.

it burped 57 hz. that was also the day the spider came unglued, but not from the comp. after the first run i was showing it to some of the guys there and played some low freq's before i re-adjusted my settings and over exerted the brahma. but even with only half the spider glued on it still hit a 143.something.

[JProtege]

If i remember correctly did you use some sort of CAD to design your enclosure? I could swear you had some sort of writeup on your progress somewhere . . . maybe on the "other" forum??

anyway, thanks for your input. I guess it never really hit me what kind of accomplishment ~150db is on one sub.

Is there some sort of standardized way of measuring output? I mean like, how far the mic is, what kind of mic, etc.

I know you do comps and whatnot so you must be fairly familiar. (and I use the term 'fairly' very loosely since you did manage 150db from a single woofer)

[jnorion]

Program is WinISD... has a huge database of drivers. You can download it here

[blue LEDz]

Program is WinISD... has a huge database of drivers. You can download it here

yup, that's what i used for the basic design. it's a darn good program for a free one.


as for metering standards, they are usually with the mic placed 4" up from the dash, 12" in from the passenger side A-pillar, and 1" from the windshield. there are other organizations that measure at the port and crap like that. some smaller comps will place the mic in the passenger side foot well because you'd generally score a higher number and that makes new kids feel better about their systems


as for a write up, this was for a different enclosure, and now the pics don't come up because imagestation sucks:http://www.wihandyman.com/forum/showthread.php?t=810