Box volume

[57459]

I have a pair of MW 267. These are Morel speakers. Their specifications are as follows:
frequency response 25-3000 Hz
resonance frequency (fs) 25 Hz
effective piston area (S) 219 cm squared
equivalent gas air load (VAS) 113 liters
moving mass (MMs) 24 gm
total Q. factor (Q/T) 0.33
electrical Q. factor (QES) 0.4
mechanical Q. factor (QMS) 2.08
suspension compliance (CMS) 1680 uM/newton

if I'm missing any information needed to calculate the appropriate closed box volume please inform me. You can find the rest of the information at the Morel web site. www.morel.co.il/drivers/woofers/mw/frameset.htm

as this is my first speaker I don't want to make a reckless mistake. Can someone tell me what the optimal volume from my enclosure is? My calculations came out to around 22 L. my enclosure is a closed enclosure. Thanks for all the help.

Eitan Waks

 

[richie00boy]

You have supplied enough T/S parameters, but one mans optimal is another mans trash can. What kind of sound are you looking for? How close to walls will the speakers live?

 

[planet10]

My sw generates boxes between 17.5 litres (0.9 Qt) and 87 litres (0.5 Q) -- a Q of 0.707 needs a 31.5 litre box.

It is hard to make a sealed box the "wrong" size. as long as it isn't too, too small (and if that is the case you can make it aperiodic)

dave

 

[Dave Jones]

My sw generates boxes between 17.5 litres (0.9 Qt) and 87 litres (0.5 Q) -- a Q of 0.707 needs a 31.5 litre box.

It is hard to make a sealed box the "wrong" size. as long as it isn't too, too small (and if that is the case you can make it aperiodic)

dave

What he said. But be aware that no sealed box is going to give you bass (F3) below the low to mid 50's. Are you planning on using a subwoofer?

 

[planet10]

What he said. But be aware that no sealed box is going to give you bass (F3) below the low to mid 50's.

But in a real room, the f10 is probably more important to getting low bass... note that the Q=0.5 curve has an F10 of 25 Hz, the lowest of the 3 curves despite having the highest F3 at 60 Hz. It also has the lowest group delay.

If you've ever heard a set of properly set up Linn Isobariks you know sealed can produce bass.

In this case bass is probably more limited by excursion capabilities.

dave

 

[57459]

Richie00Boy,
the speakers will be quite close to the wall due two architectural limitations. By quite close I mean around 50-100 cm. Maybe even closer. As to the type of sound that I am aiming for, I am not quite sure because this is my first project. I enjoy a full sound is, nothing to tight. However, I also like a very dynamic speaker. I listen to a wide-ranging of musical genres, anything from opera and classic to rap and rock.

Dave Jones,
I am not currently planning and using a subwoofer. In the beginning I was opting to use a 6 in. driver however, I decided on not using a subwoofer therefore a move to an 8 in. driver.



Thank you everyone for all replies. This form is proven to be very helpful. I attach the plans for my speaker. I would really love some critique. What your thoughts?
Total height: 425 mm
total width: 327 mm
total depth: 438 mm

 

[richie00boy]

That's a very nice design. 22 litres will give you a peak before roll-off and slightly higher -3dB point. I would say that your speakers are fairly close to walls at 0.5m and so they will gain a small amount of reinforcement. I'm not sure that your box is big enough but won't be able to check until I get home.

Can you consider a vented box? You will get quite a bit deeper output that way.

 

[planet10]

I'm not sure that your box is big enough

By my preferences & the models i generated, i would make it a bit smaller... but if you can't it would be easy enuff to make them aperiodic to lower the Q and smooth the bass peak.

dave