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-   -   Top opinions for a pair of SB Acoustics SB29NRX75-6 10Ē Woofers (http://www.diyaudio.com/forums/multi-way/124137-top-opinions-pair-sb-acoustics-sb29nrx75-6-10-woofers.html)

Jimmy154 1st June 2008 08:27 PM

Top opinions for a pair of SB Acoustics SB29NRX75-6 10Ē Woofers
 
Hello friends :Popworm:

I recently purchased a pair of SB Acoustics SB29NRX75-6 10Ē woofers: http://www.sbacoustics.com/specprodu...%20SB29NRX75-6

Madisound has slightly different Qms spec, I don't know why: http://madisound.com/catalog/product...oducts_id=8303

I modeled these with dosbox to go into a TL 1.6-1.8 meters line length, 600 cm^2 straight line with 8 kg/meter stuffing and it modeled well, I thought. Are frequencies below 20 Hz reproduced by typical amplifiers? I have a Yamaha amplifier I might be using to power these. I ask because some TL's modeled much better for driver excursion under 20 Hz than others

This woofer seems to function well up to 900 Hz, so I need to something to reproduce sound from that point up, I figure. I thought of a full-range, a horn, a Heil tweeter, and a dome midrange and tweeter combination. What would be a good option to match with this speaker? I was just going to go with a full-range because it's the easiest and I already have 4 Cambridge Soundworks full-range speakers, just lying around.

I plan to use an active cross-over at the 900 Hz point or lower, but I donít have one yet. I have seen some schematics and they seem pretty simple to build, no?

Iím having a hard time finding a single driver that covers 900-20000 Hz, which I assumed would be a 2-3Ē driver, but they arenít any that have a flat response, with good distortion figures. Maybe that is why I mostly see a dome midrange with tweeter paired with larger than 8Ē woofers; and sometimes a full-range or horn. I also like that large Heil tweeter but don't know much about it.

tomtom 1st June 2008 10:44 PM

http://markaudio.com/alpair5_intro


these are new and not much information
but they are +- evolution/continuation

of Jordan's JR6 HD and they go to 30khz

http://www.esotericaudiodevices.com/...vers/jxr6.html

they are not very sensitive - you may thinking about using 2

Jimmy154 9th June 2008 10:40 PM

Those are great 2Ē drivers. But I think I have figured out why I have not seen any many match a 10Ē and 2Ē driver. So I have decided to go with the mid/tweeter combination of http://zaphaudio.com/ZDT3.5.html I would like to use this with an active cross-over between the dome midranges and my woofers, but I canít figure out which cap(s) are responsible for high passing the midrange. I will not need that part of the cross-over, since Iím going to use an active cross-over.

Also I donít know if I want to build a TL anymore, do to its size and poorer low frequency extension vs. a ported enclosure of about half the size, according to dosbox. I donít know how a TL sounds, but I seem to dislike all the ported enclosures Iíve heard with respect to a sealed ones. The only TL I have heard (not sure if thatís what it is) is the Bose waveguide one and it sounds much better than Boseís ported designs. Is there any place near Boston I can listen to some TL enclosures?

Jimmy154 9th June 2008 11:20 PM

Quote:

Originally posted by Jimmy154
So I have decided to go with the mid/tweeter combination of http://zaphaudio.com/ZDT3.5.html I would like to use this with an active cross-over between the dome midranges and my woofers, but I canít figure out which cap(s) are responsible for high passing the midrange.
Should say: "cap(s)/components"

Dave Bullet 9th June 2008 11:44 PM

Quote:

would like to use this with an active cross-over between the dome midranges and my woofers, but I canít figure out which cap(s) are responsible for high passing the midrange
From Zaph's description of the ZDT3.5 with some edits:

The midrange uses a single capacitor (C7) for the high pass to reach LR2 along with a impedance flattening notch (L13/R14/C12) to keep the rolloff under control.

L8 and C11 are the lowpass (to the tweeter)

C10 is a notch to flatten the breakup peak at 13KHz

R6 provides level matching attenuation across the midrange bandpass

Cheers,
David.

Jimmy154 9th June 2008 11:58 PM

Oops, I think I figured out the cross-over or rather reread what zaph wrote.

Lol, yeah I read that whole page several times I thought.

Sorry, I post some really moronic questions.

I would like to listen to a TL before I build one, maybe some retails stores around me have some for sale I can listen too.

Oh! This question is not moronic :D Or maybe it is :scratch: I plan on building a Avalon Diamond type enclosure http://www.diyaudio.com/forums/showt...ghlight=avalon Of course it looks better if the woofer is about 15-20 cm away from the midrange, is this acceptable for a cross-over point of 900Hz? I'm aiming for a 4th order crossover.

tinitus 10th June 2008 12:20 AM

I wouldnt count on such a 10" to sound very good at 900hz ... also you must remember that it should be controlled/sound good past the xo point ... I think you are bound to use a 4" or 5" cone driver and cross around 300-500hz

Jimmy154 10th June 2008 12:47 AM

!
 
Quote:

Originally posted by tinitus
I wouldnt count on such a 10" to sound very good at 900hz ... also you must remember that it should be controlled/sound good past the xo point ... I think you are bound to use a 4" or 5" cone driver and cross around 300-500hz
I was thinking this earlier . . . lol . . . but it was ruining my happiness :clown: because I didn't want to build a 3-way with a cone midrange for some reason. So I decided to ignore that this woofer probably didn't sound that hot out too 900 Hz or past. But also I thought I could solve this problem by crossing it over at 900 Hz between 12-24 db/octave electrically. Small woofers made by this company seem to be able to be used until the point where you see that sudden dip in the response, so I guess in a way I convinced myself it would sound okay up to 900 HZ and a little past.

I'm so sick of this! I don't even want to build speakers, lol. All the dust gets stuck in my beautiful hair for days :( lol.

Jimmy154 10th June 2008 10:31 PM

Ok, I think I got it.

I'm going to get a CSS FR125 for the top end. I think this should be a good match, since I've never met a tweeter I liked. Maybe it won't sound as good as a 3-way, but it doesn't matter to me. I'm more of an arteest than a technical wizard ;) lol

Are there any problems with this match? :scared:

tinitus 10th June 2008 11:05 PM

With the FR125 used as a midrange distortion ought to go down so it should be able to take a little more power ... it may be worth a try, but sorry to say theres no guarantee of anything

Is it a good match with the SB 10" ?
It may depend on how the small peaking/rise around 100hz sounds
It may not be any problem at all ... you will have to try to know
But above that its a 88db, and that ought to work fine with a mid driver of a little less than 85db
A closed box of 40-50 liter ought to tame it very well

btw ... it seem theres a new model FR125 with different (better?)chassis


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