That SEOS plot is real (minimal if any smoothing), done outdoors (though that is with a particularly good DE250, not all look that good at the highest frequencies).
But I think your 2425 might be messed up (or the meas system isn't being used correctly). 20dB rolloff to 17kHz doesn't seem reasonable.
But I think your 2425 might be messed up (or the meas system isn't being used correctly). 20dB rolloff to 17kHz doesn't seem reasonable.
Earl Geddes and Tom Danley are smart guys 
Compression drivers sound very similar when eq'd the same. Most high quality drivers are similar in performance. Bigger ones go louder and lower but sacrifice top octave performance. The latest generation of large format drivers seem to have very nice compromises though.
Compression drivers sound very similar when eq'd the same. Most high quality drivers are similar in performance. Bigger ones go louder and lower but sacrifice top octave performance. The latest generation of large format drivers seem to have very nice compromises though.
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No surprise. Plastic diaphragm plus eq = similar sound
For a different flavour try a different diaphragm
Aluminium done well = radian
Titanium done well = RCF N450
Both sound very different but equally good
Thanks for your input.
I think you're right, something must be wrong. I've used LMS for many years, so I doubt my technique is the problem.
I will swap the 2425 with another driver to see whether it still exhibit the same slope.
I guess you don't see the ( historical ) significance of having just compared ( & found that they sound the same once EQed ) one driver that employs a ( plastic coated ) titanium diaphragm vs another that uses a plastic ( polyimide ) diaphragm.
Being devoid of any ( forum-learned ) anti-titanium bias is ( in it's own way ) a double-blind test of some sort .
Couldn't find data 2342 horn other than a picture where its mounted in cinema speaker system and from that picture it looks a lot like Bi-Radial 2344A.
At this link (2344) is JBL official data 2425 mounted in 2344A (look the non EQ one) and that looks not so crazy different from your own posted measurement if that is also without any EQ.
In below REW overlay plot traced your 2425/2342 and that from JBL 2425/2344A datasheet and it seems those Bi-Radial horn need EQ : )
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Without EQ is a non-starter, they naturally need EQ in the crossover. In the case of constant directivity systems, that EQ can sometimes be as simple as tweaking the transfer function of the XO to provide the attenuation to the midband, which is the case in my setup running the tymphany to about 1300 I only need a 3rd order XO (due to unit matching one has a hotter >10k so has an RC link across the driver to suppress this)
Yes, compression drivers roll off at higher frequencies. Unless used with beamy horns like exponentials they need EQ to be flat. With constant directivity horns they need to be straightened out at least to first order.
I dont get the bias against EQ, if its not in the crossover with usually well behaved electronic components its likely in the mechanical construction with clunky parasitic prone mechanical ones. Nothing pure about 'without eq' imo.
I dont get the bias against EQ, if its not in the crossover with usually well behaved electronic components its likely in the mechanical construction with clunky parasitic prone mechanical ones. Nothing pure about 'without eq' imo.
Hi BYRTT
Thanks for taking the time to check it out. I'm relieved. For a moment, I thought there's something wrong with my 2425 drivers.
My measurement was without any EQ. You're right, it looks very close to the 2344A. So there's hope.
Completely agreed, these CDs are unlistenable w/o EQ IMO, unless you like boosted 5-10db in the 1-5k hz range.
Javad
POOH, that is almost hard-to-believe low end for such a small driver... 500Hz? I don't have any easy to try horns that go that low (without taking something else apart, which would be a mess). That's not boosted on the low end at all? Can you post a photo of what your horn looks like? I'd be curious about how the distortion of the driver does at lower frequencies at, say, 90dBSPL or so, might be worth ripping into one of my old wood horns to find out.
BTW, I think JShadzi was saying that the response without EQ on the drivers will sound as if it IS boosted in the 1k to 5k range (not how to EQ it). At least that's how I read it.
BTW, I think JShadzi was saying that the response without EQ on the drivers will sound as if it IS boosted in the 1k to 5k range (not how to EQ it). At least that's how I read it.
It's a big horn - like this
Community Fiberglass Horn Lens 1" Bolt on Single w O Driver Clean See Photos | eBay
I am using a resistor and cap to pad down the midrange attempting to use it in a 2 way - no eq on the low end.
Community Fiberglass Horn Lens 1" Bolt on Single w O Driver Clean See Photos | eBay
I am using a resistor and cap to pad down the midrange attempting to use it in a 2 way - no eq on the low end.
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