hello,
what do you think of this design for a vented concrete box?
the driver is Tang Band W8-2145 8"
spec-sheet
the box volume is ~ 5550CM3
can you help me figure out if the box volume is big enough and what are the port measurements?
and one more question, would you use a close or ported design for this driver?
what do you think of this design for a vented concrete box?
the driver is Tang Band W8-2145 8"
spec-sheet
the box volume is ~ 5550CM3
can you help me figure out if the box volume is big enough and what are the port measurements?
and one more question, would you use a close or ported design for this driver?
Attachments
Sealed comes in at 31.14 liters for an f3 of 71 hertz...ported will get you well towards the bottom at an f3 of 36 hertz, for deep bass, unfortunately at a price of 79.28 liters worth of inside volume.
Both of which is a greater inside volume of your design.
------------------------------------------------------------------------Rick........
Both of which is a greater inside volume of your design.
------------------------------------------------------------------------Rick........
Some thoughts:
- The cabinet, as Richard points out, is on the small side for this driver. You might get away with the sealed box option if you can throw some EQ around. You could also consider an 8" passive radiator on the back (instead of the port), but that will also need lots of EQ.
- Having the driver at the focal point of a curved surface is the worst-case for diffraction (on the outside edge of the cabinet) and internal reflections. The former cannot be fixed without altering the surface finish (although a big roundover would go a long way to alleviating the issue), and the latter would need lots of internal absorption.
Chris
- The cabinet, as Richard points out, is on the small side for this driver. You might get away with the sealed box option if you can throw some EQ around. You could also consider an 8" passive radiator on the back (instead of the port), but that will also need lots of EQ.
- Having the driver at the focal point of a curved surface is the worst-case for diffraction (on the outside edge of the cabinet) and internal reflections. The former cannot be fixed without altering the surface finish (although a big roundover would go a long way to alleviating the issue), and the latter would need lots of internal absorption.
Chris
thank you all for the quick response ! i am learning a lot, also i'm sorry for any grammar mistake, English is not my native Tongue.
Richard Ellis, if you say 79.28 liters that's 16 times bigger then what i design!
on one hand because the "looks" of the box are a major major factor i guess that i prefer a sealed design, on the other i am very in to bass (RNB,elctronic,Hip-hop...).
question - if a sealed box job is to kill all sound waves from going out, why dose size matters?
question 2 - if the Tang Band W8-2145 specs graph show 85db in 50HZ isn't that what i will get from a good sealed box?
i will try WinISD, and will post another design soon, thank you.
chris661, using a passive radiator is interesting, can you elaborate? if i understand it's a way to produce more bass on a small sealed box. what is the down side.
Having the driver at the focal point is something i did not think of as an issue, thank you i will consider that.
Richard Ellis, if you say 79.28 liters that's 16 times bigger then what i design!
on one hand because the "looks" of the box are a major major factor i guess that i prefer a sealed design, on the other i am very in to bass (RNB,elctronic,Hip-hop...).
question - if a sealed box job is to kill all sound waves from going out, why dose size matters?
question 2 - if the Tang Band W8-2145 specs graph show 85db in 50HZ isn't that what i will get from a good sealed box?
i will try WinISD, and will post another design soon, thank you.
chris661, using a passive radiator is interesting, can you elaborate? if i understand it's a way to produce more bass on a small sealed box. what is the down side.
Having the driver at the focal point is something i did not think of as an issue, thank you i will consider that.
This driver works in big cabinets, not in small. And getting real bass out of the size you prefer won't happen, with any fullrange driver. That is pure physics.
The smallest i know, and that i build is a 17.9L ported cabinet with the Mark Audio 10.3M driver. That is tuned to 45Hz. I have the plans ready if you want them. But the driver you want to use needs a much bigger cabinet. There is no way this driver will give you the response you want in that size.
The smallest i know, and that i build is a 17.9L ported cabinet with the Mark Audio 10.3M driver. That is tuned to 45Hz. I have the plans ready if you want them. But the driver you want to use needs a much bigger cabinet. There is no way this driver will give you the response you want in that size.
Your English is fine, and better than some native speakers! 
A sealed box will try to stop the cone from moving - the air inside will resist compression.
A smaller sealed box resists compression more, so the cone finds it harder to move. ie, lower efficiency. A larger sealed box (NB - the frequency response published by the manufacturer is usually made with a very very large sealed box) will allow the cone to move more easily.
A passive radiator can be used instead of a port, if we want to tune fairly low in a small box. The downside is typically cost, especially since the PR needs to have 2x the available cone excursion of the main driver.
Given your musical interests, I'd consider moving to a multi-way speaker. I usually find that full-range speakers struggle when lots of bass is required. Dedicated woofers do a much better job.
Chris
A sealed box will try to stop the cone from moving - the air inside will resist compression.
A smaller sealed box resists compression more, so the cone finds it harder to move. ie, lower efficiency. A larger sealed box (NB - the frequency response published by the manufacturer is usually made with a very very large sealed box) will allow the cone to move more easily.
A passive radiator can be used instead of a port, if we want to tune fairly low in a small box. The downside is typically cost, especially since the PR needs to have 2x the available cone excursion of the main driver.
Given your musical interests, I'd consider moving to a multi-way speaker. I usually find that full-range speakers struggle when lots of bass is required. Dedicated woofers do a much better job.
Chris
if the problem is aesthetic due to the imported clutter of the box, you can study a solution that takes advantage of the space behind the TV to develop the volume necessary for the proper functioning of the driver
a 43-inch TV has an average width of 35 inches by a height of 20 inches. if you can distance it 8-10 inches from the rear wall you have a total cubic volume of at least 3 cubic feet
a 43-inch TV has an average width of 35 inches by a height of 20 inches. if you can distance it 8-10 inches from the rear wall you have a total cubic volume of at least 3 cubic feet
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