Sealed vs Ported (Best Guess)!

[Surtsey]

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?

 

[Sonce]

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.

 

[chris661]

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

 

[TBTL]

'Bass driver', '6.5 inches' and '92 dB' is an unusual combination.

 

[Surtsey]

The measurements were external. Maths is not my best subject but I have an internal volume of 15 litres - not 50.

 

[JensenHealey]

Are there any other identifying labels or numbers on the driver?

 

[chris661]

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

 

[Sonce]

The measurements were external. Maths is not my best subject but I have an internal volume of 15 litres - not 50.

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.

 

[Surtsey]

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.

 

[Sonce]

70-80Hz? Those 5.1 systems are toys, any half-decent 6.5" should be tuned below 65Hz. Try at 60Hz for a start.

 

[Surtsey]

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.

 

[GM]

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

 

[Surtsey]

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

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.

 

[GM]

On your workbench or........?

GM