hi, guys!
I got some 8" drivers from local manufacture. Although these drivers are not famous brand, they are quite great. Here are some information of this driver:
Fo 45Hz
Qts 0.5
Frequency Resopnse 45~20000
pressure sensitivity: 92db
flux densitity: 16000 gauss
with sub cone
Yes, these drivers are full-range drivers.
Now I wonder if it is work using them to build up subwoofer (four unit per channel). I would like them produced some low frequency sound like between 35~1000 Hz.
Can it be done?
Any recommendation or suggestion will be appreciated!
I got some 8" drivers from local manufacture. Although these drivers are not famous brand, they are quite great. Here are some information of this driver:
Fo 45Hz
Qts 0.5
Frequency Resopnse 45~20000
pressure sensitivity: 92db
flux densitity: 16000 gauss
with sub cone
Yes, these drivers are full-range drivers.
Now I wonder if it is work using them to build up subwoofer (four unit per channel). I would like them produced some low frequency sound like between 35~1000 Hz.
Can it be done?
Any recommendation or suggestion will be appreciated!
the JBL control1 subwoofer uses 4 8" cones in a double bandpass enclosure to achieve exactly this. I always thought it sounded a bit crap though. But it certainly can be done. Also the low frequency unit in certain KEF reference speakers uses small speakers facing inwards onto 5 faces of a cube shaped enclosure with a large port on the sixth face to let the bass out. And those sound incredible.
Yes, you can use 4X of those drivers to make a SW.
Put them in an appropriately sized and tuned vented enclosure. You need speaker modelling software. You also need to know the Vas parameter for the drivers in order to run the software.
You will have to be SURE that HF energy does not get into the SW, given the full range nature of the drivers.
Put them in an appropriately sized and tuned vented enclosure. You need speaker modelling software. You also need to know the Vas parameter for the drivers in order to run the software.
You will have to be SURE that HF energy does not get into the SW, given the full range nature of the drivers.
I would say that with a an Fs of 45 Hz and a Qts of 0.5, you can get pretty flat response down to 35 Hz or so in a box that is abut six times the Vas of ONE driver.
Do you know what the Vas of one single driver is?
Also, if you arrange the speakers in a square pattern, two sets of two, like this:
00
00
your sensitivity goes up about 6 dB, to 98 dB. Pretty good deal.
Again, what is the Vas of one driver, if you have the spec?
Do you know what the Vas of one single driver is?
Also, if you arrange the speakers in a square pattern, two sets of two, like this:
00
00
your sensitivity goes up about 6 dB, to 98 dB. Pretty good deal.
Again, what is the Vas of one driver, if you have the spec?
Thanks you guys reply so quickly! 
Thanks!
I don't know of the Vas of this driver, but I can ask the supplier to get the information.
I made my decision to bluild SW using the suggestion form kelticwizard.
Can the enclosure be Onken form? If so, I can put another same dirver on the top to get mid- and hige-ragne sound.
Thanks!
I don't know of the Vas of this driver, but I can ask the supplier to get the information.
I made my decision to bluild SW using the suggestion form kelticwizard.
Can the enclosure be Onken form? If so, I can put another same dirver on the top to get mid- and hige-ragne sound.
Try to get all the Thiele-Small parameters for the driver, including DC resistance.
Don't forget that if you do use a mid/tweet combo with these, the mid has to be about 98 dB sensitive as well to match. This would require either an expensive hifi speaker, or a PA speaker for the mid.
The other method is to take two 8 ohm mids of 91 or 92 dB sensitivity and run them in parallel. The two speaker unit will rate out at 97 or 98 dB sensitive at the 8 ohm voltage rating of 2.8 volts. Will explain in more detail later, if you want.
Would be very interested in knowing if your 8 inchers are 8 ohmers or 4 ohmers, and how that 92 dB sensitivity rating was achieved-at 2.8 volts or at one watt-there can be a difference.
Don't forget that if you do use a mid/tweet combo with these, the mid has to be about 98 dB sensitive as well to match. This would require either an expensive hifi speaker, or a PA speaker for the mid.
The other method is to take two 8 ohm mids of 91 or 92 dB sensitivity and run them in parallel. The two speaker unit will rate out at 97 or 98 dB sensitive at the 8 ohm voltage rating of 2.8 volts. Will explain in more detail later, if you want.
Would be very interested in knowing if your 8 inchers are 8 ohmers or 4 ohmers, and how that 92 dB sensitivity rating was achieved-at 2.8 volts or at one watt-there can be a difference.
Peleus said:hi, guys!
I got some 8" drivers from local manufacture. Although these drivers are not famous brand, they are quite great. Here are some information of this driver:
Yes, these drivers are full-range drivers.
Now I wonder if it is work using them to build up subwoofer (four unit per channel). I would like them produced some low frequency sound like between 35~1000 Hz.
Can it be done?
In my considered opinion, no not really, it won't work well.
The parameters for the full range driver, especially dual cone
and top end response IMO point to extremely limited excursion.
(This is true for all good efficiency full range drivers)
For 4 drivers efficiency will be high - 98dB/W but power handling
low, and maximum SPL's in the bass extremely limited compared
to using 8" bass only or bass/mid only units.
The endeavour only makes sense if driving power < ~15 watts.
sreten.
hi, Kelticwizard,
I very appreciate your reply.
Today, I got the Vas of this driver and it is 60 around, and the supplied didn't sure the Vas. So, It may not be correct!
The resistence of this driver is 8 ohm, but I didn'g know the DC resistence. As usual, I can ask the supplier.
In my original plan, I will use these 10 full-range 8" drivers to build a loudspeaker. Now I used them to build a open-baffle form loudspeaker and 5 units per channel. The size of baffle is 100cm X 160cm. The speaker now I used is not only quit big but also getting almost no low frequency sound. I check fomula of open-baffle form and found if I need the 40 Hz around sound, the size of baffle will need 2 Meter aquare! That is too huge to build and use. And, most important, my wife will kick me off if I put them in the living room!
So, The ten dirvers are only what I have, and no more budget to buy new ones. If I use four units to build SW, then I got only one for Mid- and High-range. One friedn of mine try to build LS with this driver and Altec 515 B and comment "May not need the mid-range drivers!"
Any suggestion?
Hi, Sreten, thanks for your comments!
Due to the limited budget, I have to use these drivers as well as I can, although they are full-range. One point, I believed, could be a good reason for building SW with this unit. That is high flux densitity, 16000 gauss! May be I am wrong! But I think this point make the unit to produce good bass! My ideal bass is deep and fast!
About the Amp, I will build a se tube amp for the SW, using 5965 DC 6528, or 6C45PE DC 300B. This kind tube amp will produced very dynamic sound. In my personal impression, this kind amp make music kind "fast", coming soon and stop soon.
I very appreciate your reply.
Today, I got the Vas of this driver and it is 60 around, and the supplied didn't sure the Vas. So, It may not be correct!
The resistence of this driver is 8 ohm, but I didn'g know the DC resistence. As usual, I can ask the supplier.
In my original plan, I will use these 10 full-range 8" drivers to build a loudspeaker. Now I used them to build a open-baffle form loudspeaker and 5 units per channel. The size of baffle is 100cm X 160cm. The speaker now I used is not only quit big but also getting almost no low frequency sound. I check fomula of open-baffle form and found if I need the 40 Hz around sound, the size of baffle will need 2 Meter aquare! That is too huge to build and use. And, most important, my wife will kick me off if I put them in the living room!
So, The ten dirvers are only what I have, and no more budget to buy new ones. If I use four units to build SW, then I got only one for Mid- and High-range. One friedn of mine try to build LS with this driver and Altec 515 B and comment "May not need the mid-range drivers!"
Any suggestion?
Hi, Sreten, thanks for your comments!
Due to the limited budget, I have to use these drivers as well as I can, although they are full-range. One point, I believed, could be a good reason for building SW with this unit. That is high flux densitity, 16000 gauss! May be I am wrong! But I think this point make the unit to produce good bass! My ideal bass is deep and fast!
About the Amp, I will build a se tube amp for the SW, using 5965 DC 6528, or 6C45PE DC 300B. This kind tube amp will produced very dynamic sound. In my personal impression, this kind amp make music kind "fast", coming soon and stop soon.
Well if driving power is low it does make sense.
~ 60L / 2cuft Vas per driver and Q = 0.5.
For 4 units indicates some seriously big boxes.
I'd be tempted to go Isobaric speaker pairs, reflexed.
Indications are this would need ~ 75L box tuned to
36Hz, this would give you -3dB at 40Hz.
Really a question of what box size is acceptable.
sreten.
~ 60L / 2cuft Vas per driver and Q = 0.5.
For 4 units indicates some seriously big boxes.
I'd be tempted to go Isobaric speaker pairs, reflexed.
Indications are this would need ~ 75L box tuned to
36Hz, this would give you -3dB at 40Hz.
Really a question of what box size is acceptable.
sreten.Keep in mind, too, that when used as a sub these will have to displace some air. Four 8s have about the same cone area as a single 15, so it has some potential, but depends upon the linear stroke of the driver. Would you run a 15" driver with 3mm of linear stroke as your sub? If not, you may be doing that unwittingly with the quad 8 woofer setup. And limit yourself to under 90 dB linear at 20 Hz because of that small stroke.
Personally, I'd look at other drivers with a lower Fs and make sure they have some stroke capability - 8+mm would be a good starting point. You'd be surprised how much stroke you need just to get to 95-98 dB peaks without excessive compression or distortion...
Dan Wiggins
Adire Audio
Personally, I'd look at other drivers with a lower Fs and make sure they have some stroke capability - 8+mm would be a good starting point. You'd be surprised how much stroke you need just to get to 95-98 dB peaks without excessive compression or distortion...
Dan Wiggins
Adire Audio
Subwoofer
A lot of people use the Fostex units in a similar manner, always trying to squeeze more bass out of them. It rarely works, and most end up adding a sub later. "Full range" is a figment of someone's imagination.
Agree that what you have there is not a bass unit. Excursion is probably only a few mm. By forcing the tuning as low as possible, you will probably lose some fidelity in the midrange, and roll the efficiency off as you go lower. That is, they are probably 92dB midband, but 82dB at 50 Hz.
Why not just use them as intended, say down to 65 Hz, and add a sub when you can. An array of four would be quite a set-up with your tube amp if not forced to go low, and may provide very nice bass extension, if not terribly low.
You will need the rest of the TS parameters for you or someone else to pick the appropriate box (Qes, Qms, Vas, Xmax, Re, etc.)
Tim
A lot of people use the Fostex units in a similar manner, always trying to squeeze more bass out of them. It rarely works, and most end up adding a sub later. "Full range" is a figment of someone's imagination.
Agree that what you have there is not a bass unit. Excursion is probably only a few mm. By forcing the tuning as low as possible, you will probably lose some fidelity in the midrange, and roll the efficiency off as you go lower. That is, they are probably 92dB midband, but 82dB at 50 Hz.
Why not just use them as intended, say down to 65 Hz, and add a sub when you can. An array of four would be quite a set-up with your tube amp if not forced to go low, and may provide very nice bass extension, if not terribly low.
You will need the rest of the TS parameters for you or someone else to pick the appropriate box (Qes, Qms, Vas, Xmax, Re, etc.)
Tim
Hi, Sreten, thanks for your quickly reply!
UK is a beautiful country, my wife and me choosed London for our honeymoon one year ago. Until now, UK is still the only country we must revisit.
For size of the enclosure, I and my wife should accept king size. I more like the Onken form enclosure.
Any suggestion about the size of enclousre?
UK is a beautiful country, my wife and me choosed London for our honeymoon one year ago. Until now, UK is still the only country we must revisit.
For size of the enclosure, I and my wife should accept king size. I more like the Onken form enclosure.
Any suggestion about the size of enclousre?
Just thought I would point out that you can make an enclosure that is both Onken and isobaric at the same time. Jaycar of Australia builds the boxes ready-made, but of course you can build one yourself.
http://www.diyaudio.com/forums/showthread.php?postid=183512#post183512
I have never built an isobaric enclosure, so I cannot vouch for them. But I figured I would let you know the option is available.
http://www.diyaudio.com/forums/showthread.php?postid=183512#post183512
I have never built an isobaric enclosure, so I cannot vouch for them. But I figured I would let you know the option is available.
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