Hey, I just spent a week building a nice sub box that turned out to sound quite pathetic. I'm quite disappointed in myself because it "kicked" about as much as my subwoofer that was included with a $30 set of computer speakers. I'll set up the situation and if you can please help me pinpoint what went wrong.
materials:
TB 8" sub (aka PE special 2 weeks ago)(used speaker sealing caulk)
70w dayton plate amp
ported enclosure of .75ft^3 (21L)
-> I put in some cheap foam I had lying around
Problem: Sub is not loud at all, even with amp gain at 100%. I messed with the LPF and gain and neither produced a "kick". The box also produced a "whizzing" type noise (I have no insight about this). I don't know if this help you diagnose the problem but it barely felt like there was any air moving through the port. Could the foam I used be useless and perhaps part of the problem?
Solution: ?. I would very much like to keep this box as I spent so long sanding smooth and putting PE laminate over. It looks quite good, just sounds pathetic. I don't believe I have an air leak. Do I need a more powerful amp?
THe video from realmofexcursion had a 100w kenwood amp with the tb and as you can see it kicks 1000x more than mine:
http://realmofexcursion.com/videos/TangBand/w8740c.2.wmv
materials:
TB 8" sub (aka PE special 2 weeks ago)(used speaker sealing caulk)
70w dayton plate amp
ported enclosure of .75ft^3 (21L)
-> I put in some cheap foam I had lying around
Problem: Sub is not loud at all, even with amp gain at 100%. I messed with the LPF and gain and neither produced a "kick". The box also produced a "whizzing" type noise (I have no insight about this). I don't know if this help you diagnose the problem but it barely felt like there was any air moving through the port. Could the foam I used be useless and perhaps part of the problem?
Solution: ?. I would very much like to keep this box as I spent so long sanding smooth and putting PE laminate over. It looks quite good, just sounds pathetic. I don't believe I have an air leak. Do I need a more powerful amp?
THe video from realmofexcursion had a 100w kenwood amp with the tb and as you can see it kicks 1000x more than mine:
http://realmofexcursion.com/videos/TangBand/w8740c.2.wmv
This guy?
8 Tang Band W8-740C 264-854
Specifications: Power Handling: 150 watts RMS/300 watts max *VCdia: 2" *Impedance: 4 ohms *Re: 3.2 ohms *Frequency range: 28-1,000 Hz *Fs: 28 Hz *SPL: 84 dB 2.83V/1m *Vas: .81 cu. ft. *Qms: 10.53 *Qes: .30 *Qts: .30 *Xmax: 12mm *Dimensions: A: 8-1/4", B: 7-1/4", C: 4-3/4"
See attached.
Recommemed box size is .26ft3 for ported.
8 Tang Band W8-740C 264-854
Specifications: Power Handling: 150 watts RMS/300 watts max *VCdia: 2" *Impedance: 4 ohms *Re: 3.2 ohms *Frequency range: 28-1,000 Hz *Fs: 28 Hz *SPL: 84 dB 2.83V/1m *Vas: .81 cu. ft. *Qms: 10.53 *Qes: .30 *Qts: .30 *Xmax: 12mm *Dimensions: A: 8-1/4", B: 7-1/4", C: 4-3/4"
See attached.
Recommemed box size is .26ft3 for ported.
Attachments
link to recommendations;
http://www.partsexpress.com/resources/indexes/sb_guide.html
Put a few bricks in a sock and put them at the bottom of the box and see if the sound changes. If you can remove any of the panels, partion the box to reduce the volume.
http://www.partsexpress.com/resources/indexes/sb_guide.html
Put a few bricks in a sock and put them at the bottom of the box and see if the sound changes. If you can remove any of the panels, partion the box to reduce the volume.
I ran your design through Unibox..
First, I believe your port diameter is too small..
with a 1.5"/7" length your tuning is ~ 28hz However unibox preduicts you need atleast a 3" port.. The noise you may be hearing is port turbulance...
Not an expert on these things, so you probably want a second opinion...
--Chris
First, I believe your port diameter is too small..
with a 1.5"/7" length your tuning is ~ 28hz However unibox preduicts you need atleast a 3" port.. The noise you may be hearing is port turbulance...
Not an expert on these things, so you probably want a second opinion...
--Chris
You are well over the speed limit for your smallish port.
You are reaching Mach 0.21 or 256 km/h or 155 miles per hour.
I bet your port isn't even flared.
You need at the VERY least a 2.25 inches diameter port. Please, flare it.
As you can see, it might be hard to fit in your small box, the BEST thing to do would be to get a passive radiator. You could stay with the small box and achieve the same tuning without an ugly long port.
Maybe this would do, I would need to check in WinISD to be sure.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-494
A more powerful amplifier would not help you much because it would increase the speed of air again. With a proper passive radiator, a more powerful amplifier will help for sure.
You could seal the box for a temporary solution with a pair of socks VERY tightly packed and yes I'm serious. You won't have the whizzing sound anymore. Since it will now be a sealed box, a more powerful amplifier could help.
You are reaching Mach 0.21 or 256 km/h or 155 miles per hour.
I bet your port isn't even flared.
You need at the VERY least a 2.25 inches diameter port. Please, flare it.
As you can see, it might be hard to fit in your small box, the BEST thing to do would be to get a passive radiator. You could stay with the small box and achieve the same tuning without an ugly long port.
Maybe this would do, I would need to check in WinISD to be sure.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-494
A more powerful amplifier would not help you much because it would increase the speed of air again. With a proper passive radiator, a more powerful amplifier will help for sure.
You could seal the box for a temporary solution with a pair of socks VERY tightly packed and yes I'm serious. You won't have the whizzing sound anymore. Since it will now be a sealed box, a more powerful amplifier could help.
If you decide the PR route, these are quite reasonable and have a bolt for adjusting the amount of weight
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-494
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-494
I went with 2 x 2" x 14" ports in my approx 1 ft3 box, it sounds good:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=26845
http://www.diyaudio.com/forums/showthread.php?s=&threadid=26845
Here's what I've summed up:
(1)I need to decrease the int. vol. of the box. I'll try and think of something light-weight and solid, after testing it.
(2)Need to fix flawwed port. I will either make the current one a dummy port and seal it and add a passive radiatior to the bottom of the box or enlarge the port and make it flared (will probably buy one off PE)
(1)I need to decrease the int. vol. of the box. I'll try and think of something light-weight and solid, after testing it.
(2)Need to fix flawwed port. I will either make the current one a dummy port and seal it and add a passive radiatior to the bottom of the box or enlarge the port and make it flared (will probably buy one off PE)
Just to point out:
- There is no "kick" at all below the classic 80Hz subwoofer crossover frequency. "Kick" frequencies are in the 70Hz to 400Hz range.
- Subwoofers are intended to play rumble and vibrations, and that's how they sound when they are not mated with a proper "bass" system capable of playing "kick" frequencies properly.
- Sets of $30 computer speakers use the "sub" to play also the "kick" frequency range, they are crossed over quite above 80Hz (more like around 300Hz, since the tiny satellites doesn't go much below that).
- There is no "kick" at all below the classic 80Hz subwoofer crossover frequency. "Kick" frequencies are in the 70Hz to 400Hz range.
- Subwoofers are intended to play rumble and vibrations, and that's how they sound when they are not mated with a proper "bass" system capable of playing "kick" frequencies properly.
- Sets of $30 computer speakers use the "sub" to play also the "kick" frequency range, they are crossed over quite above 80Hz (more like around 300Hz, since the tiny satellites doesn't go much below that).
Obviously you havent heard my system... sub crossed ~60hz. When a real bass drum kicks, you feel the impact. At close proximity the rest of the system 'smears' over the true fundemental, but you get 75feet away and all you hear is the lowest punch. I'm also talking a 15" driver with around 3inches peak-peak excursion and 1200watts to it.
I say seal the sub, take out all the stuffing. If that doesnt help, double check the amp settings and your connections. A smaller box leads to less efficiency and LESS apparent loudness(unless of course you make it highly resonant in which case it will just sound one-note boomy)
EAG don't reduce the volume of the box. You'll just run into more problems.
Your port will need to be even longer if you wish to keep the same tuning point. Your box tuning is quite good as it is now. I would just try to fit a longer port in that box, maybe a slot port.
Instead, going with a passive radiator or closing the port are better solutions.
BTW you could remove the foam to see if it makes a difference.
Start by closing the port to see if the whizzing noise is still there.
Your port will need to be even longer if you wish to keep the same tuning point. Your box tuning is quite good as it is now. I would just try to fit a longer port in that box, maybe a slot port.
Instead, going with a passive radiator or closing the port are better solutions.
BTW you could remove the foam to see if it makes a difference.
Start by closing the port to see if the whizzing noise is still there.
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