I am listening to new SB 23NRX45-8 woofers in flimsy cardboard boxes sitting on top of my 12p Pensils and I am puzzled. They sound great! I bought them as woofers after reading about a posters use of them on OB with the 12p so I cut some holes in cardboard boxes and hooked them up to my 300b mono blocks to break them in. Maybe my hearing is shot but they sound rich and full and only just missing treble as I listen to a cello concerto. Anyways, I wondering if anyone has any experience using these as full rangers with a super tweeter or such. I know that makes them 2 way so this can be moved to the multiway forum.
Jp
Jp
I'm not to surprised, but your plan to add a super tweeter is a bad idea. Stick to your initial plan.
Lets take a look: http://www.solen.ca/pdf/sb/sb23nrxs458.pdf
Beautiful until 1khz. Still not bad until 2khz. Then it starts to have some fairly aggresive break up. Listening full range might sound decent right now, and anything "wrong" in the high frequencies might sound like they can be fixed with a tweeter, but not so. We can see that driver makes sound all the way to 8khz! So it sounds like all it needs is some upper end fill in. But it won't be good sound. Especially when you start to turn things up. That break up will start to really scream at you.
Very nice woofer though. I'd try and keep everything from 1khz and up, at least 24db down from the rest of the speaker output. 48db would be much better. Maybe 30db down at 1khz and 42db down at 2khz using a 12db/oct filter. That would put the fc around 250hz. That's -6db at 250hz. You'd likely have to reverse the polarity of the alp12p.
Lets take a look: http://www.solen.ca/pdf/sb/sb23nrxs458.pdf
Beautiful until 1khz. Still not bad until 2khz. Then it starts to have some fairly aggresive break up. Listening full range might sound decent right now, and anything "wrong" in the high frequencies might sound like they can be fixed with a tweeter, but not so. We can see that driver makes sound all the way to 8khz! So it sounds like all it needs is some upper end fill in. But it won't be good sound. Especially when you start to turn things up. That break up will start to really scream at you.
Very nice woofer though. I'd try and keep everything from 1khz and up, at least 24db down from the rest of the speaker output. 48db would be much better. Maybe 30db down at 1khz and 42db down at 2khz using a 12db/oct filter. That would put the fc around 250hz. That's -6db at 250hz. You'd likely have to reverse the polarity of the alp12p.
For that kind of ap the A7.3 in an ~5 litre sealed box works well. Box for the SB i'm not sure, haven't yet looked at it yet.
Easiest to biamp, a PPLXO 1st order somewhere between 160-250 Hz would do the trick.
Passive XO would be more difficult, but given the frequency range a simple series XO could work out well. Pulling some numbers from the air one could start with 5mH + 50 uF.
dave
Easiest to biamp, a PPLXO 1st order somewhere between 160-250 Hz would do the trick.
Passive XO would be more difficult, but given the frequency range a simple series XO could work out well. Pulling some numbers from the air one could start with 5mH + 50 uF.
dave
I'd use the smaller full ranger (alp 7.3). Mating them wouldn't be a problem at all. Still shoot for the 250hz range. Or lower like Dave suggests is going for a 6db/oct slope.
If you don't know much about cross overs, and not using someone else's design, can I suggest the minidsp. Cheap to buy, works very well, easy to use, can experiment with many options. In this case, you could try 1st order all the way to 8th order and at various frequencies too. You'll need extra amps though. Or PPLXO like Dave suggested, which is a little less intuitive, but even cheaper.
If you don't know much about cross overs, and not using someone else's design, can I suggest the minidsp. Cheap to buy, works very well, easy to use, can experiment with many options. In this case, you could try 1st order all the way to 8th order and at various frequencies too. You'll need extra amps though. Or PPLXO like Dave suggested, which is a little less intuitive, but even cheaper.
Ya, don't cross at 1000hz. Here is what I do. If you want a prescription, follow this. If you don't, read and ask questions.
Buy a minidsp.
You'll need 4 channels of amplification. (if your receiver is integrated, this might be an issue)
Get the 2 way plug in (the advanced biquad plug in is better, but it's all features you won't need and will only confuse you)
Build a large ported box with the help of those here. I can try.
Build the box to include a 5 to 7L sealed enclosure inside for the alpair 7 near to the mounting hole of the SB woofer.
All that make sense so far?
Once you have the speaker built, you'll need to hook everything up. Preamp - minidsp - amplifiers - drivers.
You'll also need to program the minidsp. I can help you with that, but it's pretty easy. Just install the plug in, make the setting changes, and sync to your mini.
For starters, I'd suggest these settings.
Woofer
Level = 0db
Delay = 0ms
Low Pass = Linkwitz Riley 24db/octave at 300hz
PEQ = none needed
Full range
Level = 0
Delay = 0.6ms
High Pass = Linkwitz Riley 24db/oct at 300hz
PEQ = 6000hz, -2db, q = 3.0
Start with that and see how it goes. If it's bloated, the woofer level may need to be -1 or -2.
Buy a minidsp.
You'll need 4 channels of amplification. (if your receiver is integrated, this might be an issue)
Get the 2 way plug in (the advanced biquad plug in is better, but it's all features you won't need and will only confuse you)
Build a large ported box with the help of those here. I can try.
Build the box to include a 5 to 7L sealed enclosure inside for the alpair 7 near to the mounting hole of the SB woofer.
All that make sense so far?
Once you have the speaker built, you'll need to hook everything up. Preamp - minidsp - amplifiers - drivers.
You'll also need to program the minidsp. I can help you with that, but it's pretty easy. Just install the plug in, make the setting changes, and sync to your mini.
For starters, I'd suggest these settings.
Woofer
Level = 0db
Delay = 0ms
Low Pass = Linkwitz Riley 24db/octave at 300hz
PEQ = none needed
Full range
Level = 0
Delay = 0.6ms
High Pass = Linkwitz Riley 24db/oct at 300hz
PEQ = 6000hz, -2db, q = 3.0
Start with that and see how it goes. If it's bloated, the woofer level may need to be -1 or -2.
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That is probably an OK start, but in the end you want to dial in the XO sucj that a simple change of woofer level can be used for BSC.
I have founf that that puts the XO in the K x 4560/(width of box in inches) K is in the range root(2)/2 > 1
dave
I was thinking a 10" box is pretty likely for him. So 300hz was my first stab. I've also found with Linkwitz Riley slopes, the simple raising/lowering of the woofer achieves exactly as you say, BSC. Butterworth is to high of Q at the knee of the slope to allow for that.
There's the 6db of baffle loss, but then there's the 1 to 2db of cab diffraction right at the top of the baffle step point. I often find the diffraction to be a bigger deal than the baffle step actually. So he may need a PEQ of 650hz, -2, 1.0q.
EDIT - You may recall from the measurements I gave you on the SDX7 / LD25x speaker a wicked little diffraction peak around 650hz. You remember the baffle width of that one off hand? I couldn't take that out with a passive filter. At least not without a pricey notch.
There's the 6db of baffle loss, but then there's the 1 to 2db of cab diffraction right at the top of the baffle step point. I often find the diffraction to be a bigger deal than the baffle step actually. So he may need a PEQ of 650hz, -2, 1.0q.
EDIT - You may recall from the measurements I gave you on the SDX7 / LD25x speaker a wicked little diffraction peak around 650hz. You remember the baffle width of that one off hand? I couldn't take that out with a passive filter. At least not without a pricey notch.
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About the same width as the waveguide.
Since a diffration anomaly will be very much listener axis dependent, kinda hard to EQ it.
dave
Attachments
OK. Had way too much fun making 1 cu ft foam core cabinets and am now listening to my creation with a crude 1000hz
first order cross over consisting of a 1.5mH inductor on the woofer and a 22uF film cap on the MA 7.3. Sounds gorgeous! The cab, if you can call it that, is 20" tall by 12" wide by 9" deep with a bit of poly fill and no vent. I have them sitting on the floor toed in a bit and Gillian Welch has never sounded better. I am new to this so I am willing to call this a starting point. Anyone want to suggest incremental changes that I can easily implement? It is minus 15 Celsius here in St.John's, Newfoundland, and it is a great way to spend a Friday evening. Thanks to all!
John
first order cross over consisting of a 1.5mH inductor on the woofer and a 22uF film cap on the MA 7.3. Sounds gorgeous! The cab, if you can call it that, is 20" tall by 12" wide by 9" deep with a bit of poly fill and no vent. I have them sitting on the floor toed in a bit and Gillian Welch has never sounded better. I am new to this so I am willing to call this a starting point. Anyone want to suggest incremental changes that I can easily implement? It is minus 15 Celsius here in St.John's, Newfoundland, and it is a great way to spend a Friday evening. Thanks to all!
John
That pic didn't turn out so well. Here's another.
An externally hosted image should be here but it was not working when we last tested it.
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