bmw e30, how to improve spl?
Printed From: the12volt.comForum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=96672
Printed Date: July 07, 2025 at 11:05 AM
Topic: bmw e30, how to improve spl?
Posted By: ishy_101
Subject: bmw e30, how to improve spl?
Date Posted: August 27, 2007 at 3:18 AM
Replies:
Posted By: haemphyst
Date Posted: August 27, 2007 at 11:48 AM
With 200 watts RMS per woofer, 126dB isn't too bad, but not real SPL potential, as you have discovered... 
With those woofers, you won't get but maybe 3 to 6dB more than that, and most likely toward the lower end of the 3-6 dB range...
Three things make SPL. Efficiency, cone area, and power. 89dB with 1000 watt max power handling translates to roughly 119dB peak output, anechoic, with cabin gain making up the difference. Two of them, with 1000w each (again, peak) will make 125dB. Vented enclosure might offer an additional 3dB or so. Those woofers are NOT going to do it. You need something rated MUCH highr, efficiency-wise, like something in the CV lines. You are going to seriously compromise your low-frequency extension, though.
A properly designed bandpass could get you maybe an additional 9 to 12dB, but you still are into real SPL territory...
Basically what am trying to tell you is this: You need a: different and/or more woofers, b: VASTLY more power, c: a proper enclosure, i.e. no pre-fab boxes, period!, or potentially a different alignment (at a minumum, a vented enclosure).
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
With those woofers, you won't get but maybe 3 to 6dB more than that, and most likely toward the lower end of the 3-6 dB range...
Three things make SPL. Efficiency, cone area, and power. 89dB with 1000 watt max power handling translates to roughly 119dB peak output, anechoic, with cabin gain making up the difference. Two of them, with 1000w each (again, peak) will make 125dB. Vented enclosure might offer an additional 3dB or so. Those woofers are NOT going to do it. You need something rated MUCH highr, efficiency-wise, like something in the CV lines. You are going to seriously compromise your low-frequency extension, though.
A properly designed bandpass could get you maybe an additional 9 to 12dB, but you still are into real SPL territory...
Basically what am trying to tell you is this: You need a: different and/or more woofers, b: VASTLY more power, c: a proper enclosure, i.e. no pre-fab boxes, period!, or potentially a different alignment (at a minumum, a vented enclosure).
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: stevdart
Date Posted: August 27, 2007 at 10:13 PM