making a small (4th order)bandpass sub box and have the plate amp at the back - I'm wanting to place the port on the back panel too, above the plate amp. Seeing as all the bass output from 95 hz down to 35hz is coming out of this port, is it ok to have it facing away from the listener? I guess its non directional .. ?
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Thanks for replying - its a bedroom system, the bandpass starts rolling off acoustically at 83hz, f3 @ 100hz f6 @120hz or so but I can adjust the x/o point. I've never attempted a bandpass before so its weird not having the driver outside, just the one port
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I did think about a PR, there's a discussion on Tech Talk about this, but if it doesn't work..quite alot of time and expense
Bjorno, using a W6-1139sif, 4th order volume is 9 litres. The calculator is saying i need a v large diameter port, altho I'll go smaller as i won't reach nr it. The port is still long tho and I'm not sure how I'll fit this in the cab.
Thank you Bill, I'll give this driver a trip in my number crunching environment to see what I can do.
b🙂
Thanks Bjorno, interested to see what you get.
what i meant to say is I won't reach nr xmax(so can reduce the port diameter slightly), the amp is 50W into 4 ohms so shd be well within.
what i meant to say is I won't reach nr xmax(so can reduce the port diameter slightly), the amp is 50W into 4 ohms so shd be well within.
First: Here is a sort of large ported box (an OD-TL) that should be stuffed with damping material in order to work well:
Maybe an OD-ML-TL would minimize the needed volume...
b🙂
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Hi,
There is no reason why it cant be done in principle, but I don't like 4th order
bandpasses. Bass extension is no better than the sealed section. The extra
section forming a second order low pass is hardly every smooth, and it limits
the range of the low pass filter on the sub-amplifier, if this is set low the
extra section serves no useful purpose whatsoever (in reality).
It gives high SPL around the high pass cutoff, and generally to work well
it should be matched to small speakers with no bass at all matched to the
mechanical Q built into the subs low pass roll-off - not easy to arrange.
Poor also because the Q of the mechanical low pass is extremely sensitive
to all parameters, and the low pass output is generally nowhere near smooth.
I'd never consider one for hifi, can't see the point, AV I can, needs to be right.
rgds, sreten.
There is no reason why it cant be done in principle, but I don't like 4th order
bandpasses. Bass extension is no better than the sealed section. The extra
section forming a second order low pass is hardly every smooth, and it limits
the range of the low pass filter on the sub-amplifier, if this is set low the
extra section serves no useful purpose whatsoever (in reality).
It gives high SPL around the high pass cutoff, and generally to work well
it should be matched to small speakers with no bass at all matched to the
mechanical Q built into the subs low pass roll-off - not easy to arrange.
Poor also because the Q of the mechanical low pass is extremely sensitive
to all parameters, and the low pass output is generally nowhere near smooth.
I'd never consider one for hifi, can't see the point, AV I can, needs to be right.
rgds, sreten.
Sounds like a plan! Size it to be a bed pedestal. Even a twin size would be big enough for a low tuned TQWT.
GM
Confess I'm completely lost guys- I've looked at every type of enclosure, sealed, bandpass, reflex, PR, TL - the aim is for a very small sub(9-15 litres internal vol) with a 50W amp and at the least 40 hz f3. Its for a small room.
I looked at a W5 1138 in a TL, the Hivi M8n in a sealed and the W6 1139 in various (bandpass or BR).
I looked at a W5 1138 in a TL, the Hivi M8n in a sealed and the W6 1139 in various (bandpass or BR).
In a small [bed] room, making the sub a platform for a bed or sofa is about the best compromise, but in a sim, the MCM 55-2421 + long throw PR will do it in < 15 L net, though with just 50 W it will peak out around 100 dB/m/40 Hz.
Not current on what PRs are available, but I'm guessing you'll have to use at least a 12" to get the desired tuning unless they now offer long throw 8" or 10" PRs.
GM
Not current on what PRs are available, but I'm guessing you'll have to use at least a 12" to get the desired tuning unless they now offer long throw 8" or 10" PRs.
GM
WinISD would suggest a ~12L (internal volume) cabinet with a 2" dia port 12" long.
F3 ~38Hz, and more than enough SPL for a bedroom.
Chris
The Tang Band W6-1139.
I'm using a pair of them up to 500Hz, where they cross to Fostex drivers for the rest of the range.
For lots of bass with limited space, I'd go for this every time.
You'll be nudging 100dB in half space, so you could get considerable volume by sticking it in a corner.
Chris
I'm using a pair of them up to 500Hz, where they cross to Fostex drivers for the rest of the range.
For lots of bass with limited space, I'd go for this every time.
You'll be nudging 100dB in half space, so you could get considerable volume by sticking it in a corner.
Chris
Hi,
Ive posted a design here using the same driver that may suit your thread as well:
http://www.diyaudio.com/forums/subwoofers/221731-small-tower-subwoofer-project-2.html#post3206402
b🙂
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