Closing off the port is what I do if I can get the Q to be .7 and F3 in the range of 80 to 100Hz. But, this only works right if the lowpass in the crossover is 4th order, the highpass 2nd order and you can set the frequency to F3.
Unfortunately, crossovers with a 4th low and 2nd high are not generally available. You could use a full 4th order LR crossover and tap off in between the cascaded highpass sections but that may be more effort than you care to expend.
The option is to not close off the vent and use a full 4th order in the 100 to 120Hz range.
If you are using a plate amp for the sub you are stuck with the slopes they give you so all you can do is hope for the best although you could try it with ports closed and not closed to find out which you prefer.
Unfortunately, crossovers with a 4th low and 2nd high are not generally available. You could use a full 4th order LR crossover and tap off in between the cascaded highpass sections but that may be more effort than you care to expend.
The option is to not close off the vent and use a full 4th order in the 100 to 120Hz range.
If you are using a plate amp for the sub you are stuck with the slopes they give you so all you can do is hope for the best although you could try it with ports closed and not closed to find out which you prefer.
I have actually got a Behringer cx3400, a 3-way 4th order LR crossover. I also already have a stereo poweramp. I have absolutely no idea what the Q of the Cantons is right now, and I have no idea what ik may become when I close the ports.
The Canton has two 8 inch woofers, and already goes pretty deep. There's sufficient output at 40 hertz, and even some usable output at 30 hertz. I don't know what the F3 is. I neither know what the portfrequencie is.
Let's guess this is around 40 hertz. Say I use the crossover to let the subs start at 60 hertz. Then the port wouldn't do much anymore, right?
The Canton has two 8 inch woofers, and already goes pretty deep. There's sufficient output at 40 hertz, and even some usable output at 30 hertz. I don't know what the F3 is. I neither know what the portfrequencie is.
Let's guess this is around 40 hertz. Say I use the crossover to let the subs start at 60 hertz. Then the port wouldn't do much anymore, right?
Bill,
My speaker originally had a 3way passive crossover, crossing @ 300 hertz & 3500 Hertz. The behringer now takes care of the cross between bass and mid/high. This means the two 8" woofers are working from 300 hz down. Since they already go quite deep, wouldn't it be a waste to cut them at 120 hertz?
Say I do cross at 120 hertz, why would it not make sense to close the port?
Martin
My speaker originally had a 3way passive crossover, crossing @ 300 hertz & 3500 Hertz. The behringer now takes care of the cross between bass and mid/high. This means the two 8" woofers are working from 300 hz down. Since they already go quite deep, wouldn't it be a waste to cut them at 120 hertz?
Say I do cross at 120 hertz, why would it not make sense to close the port?
Martin
Hi Martin,
You don't really want your low bass coming from more than one source. Too hard to integrate it. It's better to cut off the small woofers and have the big one do all the lows. It may be that you will want to lower the frequency a bit, down to say 80 Hz or so and let the woofer do the rest. Plugging the ports is probably an OK thing to do.
Cal
You don't really want your low bass coming from more than one source. Too hard to integrate it. It's better to cut off the small woofers and have the big one do all the lows. It may be that you will want to lower the frequency a bit, down to say 80 Hz or so and let the woofer do the rest. Plugging the ports is probably an OK thing to do.
Cal
I want to add subs, to get even deeper bass. Point is that I already have an amp, and a crossover. I also already have 2 Visaton W 300 s woofers (8ohm version). All I have to do is build a box.
I intend to place the subs next to the main speakers, and between them. Would it matter a lot if the subdrivers would be about 12 inches further away from me then the baffle of the Cantons?
I intend to place the subs next to the main speakers, and between them. Would it matter a lot if the subdrivers would be about 12 inches further away from me then the baffle of the Cantons?
I'll concede that I'm no expert in vented box design but I've modeled your woofer in WinISD and have come to the conclusion that they will not reach any deeper than what I imagine your Cantons will do.
The compromises that will have to be made in mid-bass sound quality will overshadow any real or imagined gain in low bass performance, IMO.
Were I in your shoes, I would place the woofer so it is at the same distance from the listener as your Cantons (not 12" back as you would like). I would then cross it at 300Hz. I would then reduce the drive to the Canton woofers by 6db and adjust the the level of the Visiton so it was the same as the Canton woofers. You now have all 3 woofers effectively in parallel reproducing approximately the same frequency band at the proper level. You wind up with a system pretty much like you already have in terms of response and the sound quality should be pretty much unaffected. With each woofer now having an easier time of it in terms of excursion, I would then apply some low frequency equalization to both bass systems. Theoretically you could add a 6db boost at 30Hz.
I know this seems unconventional and some readers may yell and scream at me for such a weird idea but . .
I am curious as to what you gained by bi-amping the Cantons at 300Hz.
The compromises that will have to be made in mid-bass sound quality will overshadow any real or imagined gain in low bass performance, IMO.
Were I in your shoes, I would place the woofer so it is at the same distance from the listener as your Cantons (not 12" back as you would like). I would then cross it at 300Hz. I would then reduce the drive to the Canton woofers by 6db and adjust the the level of the Visiton so it was the same as the Canton woofers. You now have all 3 woofers effectively in parallel reproducing approximately the same frequency band at the proper level. You wind up with a system pretty much like you already have in terms of response and the sound quality should be pretty much unaffected. With each woofer now having an easier time of it in terms of excursion, I would then apply some low frequency equalization to both bass systems. Theoretically you could add a 6db boost at 30Hz.
I know this seems unconventional and some readers may yell and scream at me for such a weird idea but . .
I am curious as to what you gained by bi-amping the Cantons at 300Hz.
Hi Bill,
I have also ran the woofer through (very basic) program, and I could manage a F3 round 35 hertz with a ported design. Considering its Qts, I think ported should be the way to go.
My Cantons reach pretty deep, as I mentioned before. Maybe an inroom response that gives a F3 even a bit lower than 40 hertz. But that estimate was based on inroom response.
Wouldn't you think the actual F3 anechoic would be a bit higher? Than it would still make sense to use the Visatons below that, right?
I thought the benefit of biamping wouldn't be very big. The greatest advantage I think is that you can remove the passive components from the chain.
The difference is clearly audible. Bass is more controlled, and seems more dynamic. The midband is clearer and sounds even less colored. Instuments are more clearly seperated. I don't think the extra amp amounts in less audible amp distortion, as the distortion from one amp is already below audible level. The Cantons were previously driven with one 120 Watt amp. I always thought this was enough, but by adding a 135 watt amp (for the bass) I now have nearly 500 Watts effectively for each speaker! It now sounds much more relaxed, at even reasonably high volumes.
I have also ran the woofer through (very basic) program, and I could manage a F3 round 35 hertz with a ported design. Considering its Qts, I think ported should be the way to go.
My Cantons reach pretty deep, as I mentioned before. Maybe an inroom response that gives a F3 even a bit lower than 40 hertz. But that estimate was based on inroom response.
Wouldn't you think the actual F3 anechoic would be a bit higher? Than it would still make sense to use the Visatons below that, right?
I thought the benefit of biamping wouldn't be very big. The greatest advantage I think is that you can remove the passive components from the chain.
The difference is clearly audible. Bass is more controlled, and seems more dynamic. The midband is clearer and sounds even less colored. Instuments are more clearly seperated. I don't think the extra amp amounts in less audible amp distortion, as the distortion from one amp is already below audible level. The Cantons were previously driven with one 120 Watt amp. I always thought this was enough, but by adding a 135 watt amp (for the bass) I now have nearly 500 Watts effectively for each speaker! It now sounds much more relaxed, at even reasonably high volumes.
Thanks for your bi-amping impressions. I bi-amp myself at 90Hz.
Canton claims response down to 17Hz for your system and no doubt they are taking the room into account.
I use sealed bass myself because in my room the lift gets me fairly low and, I'm sure, fairly flat.
Sure, without room lift F3 will be at a higher frequency.
I think you should build a vented box for your woofer with a facility to close the vent off. You can play around with crossover frequencies and slopes and explore all the options (including my hairbrained idea) with two enclosure types. I'd definitely be interested in hearing about the results.
Canton claims response down to 17Hz for your system and no doubt they are taking the room into account.
I use sealed bass myself because in my room the lift gets me fairly low and, I'm sure, fairly flat.
Sure, without room lift F3 will be at a higher frequency.
I think you should build a vented box for your woofer with a facility to close the vent off. You can play around with crossover frequencies and slopes and explore all the options (including my hairbrained idea) with two enclosure types. I'd definitely be interested in hearing about the results.
IMO there are three options that I might try for this sytem, given the existing mains and the "sub" woofers that you have at your disposal for DIY cabinets:
(1) Bill's idea of paralleled "woofers" consisting of the Visaton and Canton's, both with low pass of 300Hz.
(2) Model the Canton driver/enclosure (or better yet, measure it groundplane) with ports plugged to determine the F3 and Q in sealed configuration. With a little luck, and perhaps some stuffing material of appropriate nature, you might be able to cross the sub 4th low pass at the Canton's F3 and the Canton's 2nd high pass at the same frequency.
(3) Model or measure the Canton's with ports unplugged, and cross the sub 4th at the Canton's F3. Run the Canton's fullrange. This is my least preferred option. The second is my preferred if you have the ability to properly measure and if the results are within a workable range. Bill's suggestion is a safe one that will extend the system F3 a bit without much chance of doing something really bad.
(1) Bill's idea of paralleled "woofers" consisting of the Visaton and Canton's, both with low pass of 300Hz.
(2) Model the Canton driver/enclosure (or better yet, measure it groundplane) with ports plugged to determine the F3 and Q in sealed configuration. With a little luck, and perhaps some stuffing material of appropriate nature, you might be able to cross the sub 4th low pass at the Canton's F3 and the Canton's 2nd high pass at the same frequency.
(3) Model or measure the Canton's with ports unplugged, and cross the sub 4th at the Canton's F3. Run the Canton's fullrange. This is my least preferred option. The second is my preferred if you have the ability to properly measure and if the results are within a workable range. Bill's suggestion is a safe one that will extend the system F3 a bit without much chance of doing something really bad.
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