I have a 6.5" Bass driver in a cabinet measuring 240 x 240 x 360. I have no T/S parameters for the driver apart from SPL of 92dB and frequency response from 40hz to 5Khz.
Given the cabinet size which enclosure type would be best?
Given the cabinet size which enclosure type would be best?
Assuming the dimensions are in mm and are internal measure of the cabinet, its volume is almost 50 liters, which is adequate for ported type.
Best bet is to learn to measure the driver for T/S parameters, and model accordingly.
50L is a huge box for a 6.5" driver.
Chris
50L is a huge box for a 6.5" driver.
Chris
The measurements were external. Maths is not my best subject but I have an internal volume of 15 litres - not 50.
Yeah, I just ran the numbers. Just under 21L external, so 15L internal probably isn't far off.
Much more sensible for a 6.5" driver.
Chris
Sorry, my bad, didn't noticed - my finger must have slipped on the numerical pad, it is 20 liters (external), not 50.
Anyway, it is adequate for ported enclosure.
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One more question: bearing in mind small size of the driver and cabinet is 65Hz too low a port tuning frequency. I have reverse calculated a couple of subs from off-the-shelf 5.1 systems and they are tuned between 70 and 80hz.
70-80Hz? Those 5.1 systems are toys, any half-decent 6.5" should be tuned below 65Hz. Try at 60Hz for a start.
I think it's close enough. I deal in recycled parts. I have a pair of flanged ports kicking around. If I use both Boxnotes puts me at around 65Hz, If I use only one I'm close to 45Hz. I'll try with one port then if I'm not satisfied I'll use the other.
This sub is not the love of my life. I work part-time at a charity shop. When I happen upon an 8" driver - I'll try that. And when I'm done the finished unit will go back to the charity shop.
Based on Small's vented chart [attached], ~15 L is good for ~89 dB eff./~42 Hz, ~92 dB eff./~55 Hz, so will be interesting to know which you prefer 😉: Efficiency and sensitivity conversion - loudspeaker percent and dB per watt and meter loudspeaker efficiency versus sensitivity vs speaker sensitivity 1 watt = 2,83 volt box chart - sengpielaudio Sengpiel Berlin
GM
GM
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The results thus far are unimpressive. Tuned to 45Hz I have a lot of cone movement and very little sub-bass. Don't get me wrong, the bass is good and tight, I can't dispute the quality but there's not very much of it. It's definitely there. My stereo speakers have 5" bass drivers and I can hear if the sub's on or off. I feel Boxnotes may be steering me wrong. I'm going to go with your calculations and add a second port, retuning to 65Hz.