BIB utilising twin CSS WR125ST's?

Brisso57 · 9th March 2009, 08:43 AM

I have 2 pair of WR125ST's to recycle from an earlier project. (Fatally low WAF!)

Is it feasible to mount them together (flat-to-flat) in a BIB?

What adjusted values should I enter into the BIB calculator if I wanted to do this?

I'm assuming that the calculated "z" would actually be the centreline ie where frame touches frame.

Note that a helper tweeter or supertweeter would be needed. I'm just assuming that that's not a big issue once the basics are sorted.

Can anyone assist? For that matter, has anyone tried this?

Thanks

Doug

Scottmoose · 9th March 2009, 08:54 AM

Same as any other time when you double the number of drivers.
If paralleled, Vas & Sd double, Re & Le halve. If wired in series, Vas, Sd, Bl, Re & Le all double.

Brisso57 · 9th March 2009, 09:48 AM

OK. Thanks Scotmoose.

Next question ... Is it better to orient the pair side-by-side or under-and-over?

Side by side would mean, I think, that the actual line length would be the calculated value, but the under and over arrangement would perhaps "smear" the positioning?

Would this "smearing" be detrimental? Or perhaps beneficial, if the FR response was smoother?

cheers

Doug

Scottmoose · 9th March 2009, 11:38 AM

Over-under would be preferable. You'll have to bring the tweeter in quite early to avoid combing effects.

Brisso57 · 9th March 2009, 12:03 PM

Quote:

Originally posted by Scottmoose
Over-under would be preferable. You'll have to bring the tweeter in quite early to avoid combing effects.

5000Hz?
4000Hz?

I presume that having it clearly above the 300-3000Hz band is desirable.

Doug

Scottmoose · 9th March 2009, 12:27 PM

Assuming you can get away with it, yes (although our critical hearing BW is 200Hz - 4KHz &, preferably an octave either side

). MTM should help a little with that, although nominally you're destrutive interference is going to start from the point at which the c-to-c spacing of the drivers exceeds 1 wavelength.

Cal Weldon · 9th March 2009, 03:38 PM

Hi Brisso,

Scott designed a double horn box for the two WR's as well. Something to consider and it's an easy build. It's called the Calhoun. I would recommend running the drivers as I have to remove any problem with combing and to act as a BSC. You have to squeeze every ounce of goodness from those drivers so I chose that route. I am not disappointed.

Cal Weldon · 9th March 2009, 03:40 PM

The previous use of those divers I was not happy with no matter how much I played around with them, mostly as a result of having the two drivers on the front.

chrisb · 9th March 2009, 06:47 PM

Doug:

I've heard Cal's " 'houns", and if you have the space to allow for experimenting with the tricks that the side firing drivers' soundstage / imaging allow, these work great.

You will need a tweeter, and IIRC Cal used an inexpensive Audax soft-domed wave guide unit?

planet10 · 9th March 2009, 08:27 PM

Quote:

Originally posted by chrisb
IIRC Cal used an inexpensive Audax soft-domed wave guide unit?

TangBand i think.

dave

9th March 2009, 08:43 AM	#1
Brisso57 diyAudio Member Join Date: Sep 2005 Location: the leafy west of Brisbane	BIB utilising twin CSS WR125ST's? I have 2 pair of WR125ST's to recycle from an earlier project. (Fatally low WAF!) Is it feasible to mount them together (flat-to-flat) in a BIB? What adjusted values should I enter into the BIB calculator if I wanted to do this? I'm assuming that the calculated "z" would actually be the centreline ie where frame touches frame. Note that a helper tweeter or supertweeter would be needed. I'm just assuming that that's not a big issue once the basics are sorted. Can anyone assist? For that matter, has anyone tried this? Thanks Doug __________________ A speaker-builder's parable: "That burned down, fell over, then sank into the swamp. But the fourth one stayed up. And that's what you're going to get, Lad, the strongest castle of all."

9th March 2009, 09:48 AM	#3
Brisso57 diyAudio Member Join Date: Sep 2005 Location: the leafy west of Brisbane	Driver orientation? OK. Thanks Scotmoose. Next question ... Is it better to orient the pair side-by-side or under-and-over? Side by side would mean, I think, that the actual line length would be the calculated value, but the under and over arrangement would perhaps "smear" the positioning? Would this "smearing" be detrimental? Or perhaps beneficial, if the FR response was smoother? cheers Doug __________________ A speaker-builder's parable: "That burned down, fell over, then sank into the swamp. But the fourth one stayed up. And that's what you're going to get, Lad, the strongest castle of all."

9th March 2009, 06:47 PM	#9
chrisb diyAudio Member Join Date: Aug 2002 Location: victoria BC	Doug: I've heard Cal's " 'houns", and if you have the space to allow for experimenting with the tricks that the side firing drivers' soundstage / imaging allow, these work great. You will need a tweeter, and IIRC Cal used an inexpensive Audax soft-domed wave guide unit? __________________ you don't really believe everything you think, do you? community sites t-linespeakers.org, frugal-horn.com commercial site planet10-HiFi

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9th March 2009, 08:54 AM	#2
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Same as any other time when you double the number of drivers. If paralleled, Vas & Sd double, Re & Le halve. If wired in series, Vas, Sd, Bl, Re & Le all double.

9th March 2009, 11:38 AM	#4
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Over-under would be preferable. You'll have to bring the tweeter in quite early to avoid combing effects.

9th March 2009, 12:27 PM	#6
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Assuming you can get away with it, yes (although our critical hearing BW is 200Hz - 4KHz &, preferably an octave either side ). MTM should help a little with that, although nominally you're destrutive interference is going to start from the point at which the c-to-c spacing of the drivers exceeds 1 wavelength.

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