This I would disagree with.
The 1745 might be a bit larger, but in the same size horn the 1425 is as good or better. The only real limitation becomes power handling.. and domestically that shouldn't be much of an issue.
So did I.
To the best of my knowledge there aren't any good horns that are *cheap* that extend that low (and high).
The least expensive that's good.. is presumably what jzagaja will be providing.. specifically the JMCL 400.
http://www.diyaudio.com/forums/group-buys/166312-waveguides-horns-7.html#post2188035
http://www.autotech.pl/pdf/audio_en.pdf
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"I guess it puts this experiment firmly in the expensive category."
-exactly.. depending on your notion of expensive. Certainly more expensive than the 85 dollar combo I suggested.. (..which is limited to about 1.6 kHz.)
..the JMCL400 apparently can be done for 1 or 1.4 exits. The Celestion 1425 1" exit is about 70. You'll pay more than double that for just about any decent 1.4" exit driver.
The Radian looks to be a good choice for the price for 1.4".. Here it is with eq. on a massive OS profile waveguide (post 10):
http://www.diyaudio.com/forums/multi-way/149085-testing-big-waveguide.html
..note the "dip" at 4-5 kHz near the 0 degree axis is part of the waveguide's profile.
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What are you, stuck in a limbo dance?
i.e. "how low can you go man?".. This depends on what sort of high-pass response you want. Can it reach 700 Hz near the average in a horn like the JMCL400? Almost certainly.
Take a gander at it's response in a simple plane-wave tube:
http://professional.celestion.com/pro/pdf/CDX1-1425.pdf
Substantial output lower than 600-500 Hz.. less likely.
(..though my guess is that it would be better than you would think.)
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Zilch and I both confirmed that Celestion 1425 does not play below 2KHz very well at all. It has some hugh impedance issues. I tested not only on the HPR-122i waveguide but the HPR-152i waveguides.
Im sorry Scott but we have to disagree here. Do you know how small and light the 1425 is? I think above 2KHz its a great value but if you see the impedance curves for it you will know what Im talking about. The manufacturer measurement isnt a good choice to look at. Augerpro's measurements are better, although there isnt a off axis measurement.
http://sites.google.com/site/driver...s/acoustic-elegance-td12m/celestion-cdx1-1425
I own both the 1745 and the 1425. Their price is very similar so I would pick the 1745 over the 1425 period....no reason to get the 1425.
Here is my 1425 Impedance measurement on the HPR122i, Fs is around 1200
Im sorry Scott but we have to disagree here. Do you know how small and light the 1425 is? I think above 2KHz its a great value but if you see the impedance curves for it you will know what Im talking about. The manufacturer measurement isnt a good choice to look at. Augerpro's measurements are better, although there isnt a off axis measurement.
http://sites.google.com/site/driver...s/acoustic-elegance-td12m/celestion-cdx1-1425
I own both the 1745 and the 1425. Their price is very similar so I would pick the 1745 over the 1425 period....no reason to get the 1425.
Here is my 1425 Impedance measurement on the HPR122i, Fs is around 1200
An externally hosted image should be here but it was not working when we last tested it.
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I'd thought the horn was creating the lower rise.. but Brandon clearly has it stated as "naked" (or presumably without horn).
2 LCR's instead of one..
Makes me wonder what a little work on the rear chamber would do.. It also make me wonder about the differences in fatigue between the manufacturer's data and Brandon's and yours. (i.e. perhaps their driver's had more "break-in".)
Distortion doesn't appear to b a problem however.
Interesting..
Here is the 1430 in just the stereolab 400 (and also the 1000):
Imageshack - celestiontractrixxb9.jpg - Uploaded by Imageshack user
Clearly it would need significant equalization AND impedance compensation.. BUT it does provide plenty of output down to 500 Hz.
Here is the 1430 in just the stereolab 400 (and also the 1000):
Imageshack - celestiontractrixxb9.jpg - Uploaded by Imageshack user
Clearly it would need significant equalization AND impedance compensation.. BUT it does provide plenty of output down to 500 Hz.
Nice find,
The horn (stereolab 400) can definitely push it lower but how much EQ does it need to make it flat to 500Hz...it actually looks great and wouldn't need much EQ from 1500 to 28Khz.
I wonder how it sounds though and what the max SPL at something like 700Hz would be for that driver. Off axis, distortion, CSDs would be need to see what is happening down low.
I also wonder what the cost of the 1430 is.
The 1430 is nearly identical to the 1425, and maybe 10 US more from a similar discount reseller.
With a design like that basically you subtract rather than add (looking at about a 100 db average design).. so you aren't really pushing it any lower on a non-filtered comparison. THD will be about the same. Dido for max spl.. (..the crossover really "sets" the design limitations, and many designs use a compensation filter that radically lowers THD at lower freq.s. so it most certainly isn't "equal" from this design to a more "normal" design.)
Liner decay has more to do with the high-pass nature of the system + any dominate resonance at the mouth. Of course it also matters depending on the axis measured because of the waves bounding to the walls of the horn. Most horns and waveguides have this problem though (..unless the expansion rate is really "fast" with very little transmission-line like properties).
A Le Cleac'h flare will have more output lower than the Tactrix for a given "cut-off" freq.. But it's also larger as well. It should also be better off-axis with respect to linear decay as a result. The best part though is requiring a less "steep" crossover for better "blending" of dispersion patterns to the lower freq. driver.
Depending on how steep the crossover is, a lower limit of 600 Hz (high-pass) on the Stereolab should work (with a LR4 or higher).
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I looked around for a more suitable 1" exit driver.. for lower freq. use. Radians are a natural here.. but I wanted see what else was available..
Obviously the B&CDE250.. though tough impedance compensation work.
But the one that seemed more interesting (at least as spec.ed) on a *value* basis was this driver:
http://www.parts-express.com/pdf/294-817s.pdf
Lower Fc (larger diameter). "Easier" impedance rise (assuming accurate data). Basically a surround-less design that's vented. Neo Motor. etc.. AND I've found it for a modest price (at least in the US).
RCF ND350 Driver 1.75-Inch Diaphragm, 1 Inch Exit Throat, 40W AES, 80W
Obviously the B&CDE250.. though tough impedance compensation work.
But the one that seemed more interesting (at least as spec.ed) on a *value* basis was this driver:
http://www.parts-express.com/pdf/294-817s.pdf
Lower Fc (larger diameter). "Easier" impedance rise (assuming accurate data). Basically a surround-less design that's vented. Neo Motor. etc.. AND I've found it for a modest price (at least in the US).
RCF ND350 Driver 1.75-Inch Diaphragm, 1 Inch Exit Throat, 40W AES, 80W
I've been looking at those... although, operating them below the resonance frequency is a scary proposition. The Radian drivers look best.... easily reaching down into the 500s.
How about the Radian 450PB? Maybe worth the extra $.
Radian 450PB-8 1" Aluminum Horn Driver 8 Ohm 2-Bolt | Parts-Express.com
http://www.parts-express.com/pdf/294-700s.pdf
How about the Radian 450PB? Maybe worth the extra $.
Radian 450PB-8 1" Aluminum Horn Driver 8 Ohm 2-Bolt | Parts-Express.com
http://www.parts-express.com/pdf/294-700s.pdf
some of the one inch drivers I have used-
The old Peavey 22 with the aluminum diaphragm and salt shaker phase plug is a fantastic driver (maybe without peer in a one inch)in the midrange and can be used quite low (500 hz) in a large horn at moderate spl. Hard to find with the original diaphragm though because most were abused in PA use and blown - nothing past 12K - be careful and do not damage if you find an original pair because you can't get the real aluminum diaphragms anymore and I doubt if you'll find a small format driver to equal this
The JBL 2470 can be used that low but it sounds horrid.
Small format Altecs are good to 800 Hz - nothing really good or bad about these. boring
The 1" and 1.5" radians don't sound very good. The old emilar/renkus were better but forget running them below 1200 regardless of what the manufacture claim
I've used the B&C 250, Beyma CP380, BMS 1", in 200 hz hypex horns and 300 hz tractrix horns as well as various smaller horns and they all crap out at around 1K, BMS is unlistenable imo, the B&C is better. Problem with the B&C is the better the electronics/source material used the less they impress. Both BMS and B&C suffer from the "all sounds the same" syndrome - Beyma is a little better, best of the bunch.
The TAD 2001 is OK to 600 hz and very transparent (to the point it is etched, maybe HF resonance?) but is expensive and the Peavey is better in the midrange in the same horns by quite a margin
The Celestion drivers mentioned in this thread look to be interesting but only above maybe 1200, I'd like to have some to play with
The old Peavey 22 with the aluminum diaphragm and salt shaker phase plug is a fantastic driver (maybe without peer in a one inch)in the midrange and can be used quite low (500 hz) in a large horn at moderate spl. Hard to find with the original diaphragm though because most were abused in PA use and blown - nothing past 12K - be careful and do not damage if you find an original pair because you can't get the real aluminum diaphragms anymore and I doubt if you'll find a small format driver to equal this
The JBL 2470 can be used that low but it sounds horrid.
Small format Altecs are good to 800 Hz - nothing really good or bad about these. boring
The 1" and 1.5" radians don't sound very good. The old emilar/renkus were better but forget running them below 1200 regardless of what the manufacture claim
I've used the B&C 250, Beyma CP380, BMS 1", in 200 hz hypex horns and 300 hz tractrix horns as well as various smaller horns and they all crap out at around 1K, BMS is unlistenable imo, the B&C is better. Problem with the B&C is the better the electronics/source material used the less they impress. Both BMS and B&C suffer from the "all sounds the same" syndrome - Beyma is a little better, best of the bunch.
The TAD 2001 is OK to 600 hz and very transparent (to the point it is etched, maybe HF resonance?) but is expensive and the Peavey is better in the midrange in the same horns by quite a margin
The Celestion drivers mentioned in this thread look to be interesting but only above maybe 1200, I'd like to have some to play with
I'd like to have all those drivers you just mentioned
Considering this will be my first foray into horns and CDs, I want to keep it simple and cheap. Although, it looks like its not going to be a cheap affair anymore.
Well, I just checked ebay and there is a a pair of the 22a Peavey with some horns on there for 98 bucks, see if the seller knows they are original and snag them up. You'll need a tweeter if you want response above 12Kand some better horns. the parts express 12" round conical horn is not bad when mounted on a baffle (will work down to 1k with the peavey) and can be tweaked a bit to make it excellent with the Peavey driver. I am no way affiliated with the seller so beware and make sure they have the aluminum diaphragms.
Peavey 22A Horns.Tweeter Speakers.8 Ohms.Pair.PA.22-A - eBay (item 160478683139 end time Sep-15-10 17:30:28 PDT)
That's just it, the RCF's look *better* to me than the Radian's, even the 475. (..manufacturers claims are marketing on a more "pro-sound" basis, not really for domestic use.)
Operating a driver below Fc, may not be much of a big deal because of the horn loading.. it's something you have to look at for each design.
IMO a good bit of what TrueSound is describing can be related to driver fatigue - both suspension and diaphragm. Older fatigued aluminum drivers tend to sound better.. they *age* better (..until they break). . Based on the description I suspect that the mentioned JBL 2470 had a titanium replacement diaphragm.
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