I tryid to say: difference between bright and distorted. Looking at a spectral analysis of these 2 different anomalies, they are very different of course.
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In theory, more info = good.
However, in the testing example you gave earlier:
At 2.83V the distortion started to rise under 500Hz
at 22.5V, the distortion started to rise under 500Hz
...so the higher power tests tell me exactly the same thing as the low power tests.
David Morison made the point: "If you look at 300Hz however, you can see that your top 2 sweeps show a much bigger step up in distortion than the relatively consistent increments between the lower driver levels."
...which is correct, but is (or seems to be) 100% hypothetical, for my situation. If I'm making a battery powered, personal use system, I'll never see (hear) anything like those top two sweeps.
Maybe mine too. My high noise floor may be partly due to user error 🙂
I found this on a forum when I searched for "REW clipping" -->
"I should have done a search first - someone else had the issue, and was also using the mic-in rather than the line-in. Fixed it. Thanks for the reply."
So far it looks like I will stick with the smallest - and cheapest - driver that I tried: the little Tymphany DFL-2525R00-08.
Short version: The HF is very good. The mid/LF capability is good enough, at my listening distance + level.
An important bonus for the lazy DIY dabbler: it is a bolt on driver that you don't have to bolt on from the front.
I think I'll use it on a MEH (Multiple Entry Horn).
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Long version: measured solo, the HF is better (flat and extended) than other compression drivers I've tested. Subjectively it has no nasty "steely" quality.
This is important, for me. I've tried and dumped a number of other drivers, some of them quite upmarket, for their HF breakup / steely sound.
e.g. I got irritated with this driver and sold my pair. It cost 20 times as much as the little Tymphany. The breakup should be "benign" because it is well past 10kHz - but to my ears, it wasn't benign.
https://www.bcspeakers.com/media/W1siZiIsIjIwMTMvMDMvMTEvMTUvNTMvNDMvNzgxL2ZpbGUiXV0
The little Tymphany performs well on the stress test music I tried.
e.g. the start of (The Creatures - Sky Train):
e.g. the busy parts of this (The Blood Brothers - Set Fire To The Face On Fire):
The flipside is that it is a tiny device (25mm dia), so almost anything else will beat it for demanding use (high power / PA / whatever).
To see if I could ease its LF requirements, I made (another) rough test MEH.
Test mule is 80cm wide, 40cm high, with straight side walls, curved top and bottom walls. Mids provided by one 6" driver, firing through a small tap about 7cm from the horn apex. Passively crossed at ~1500Hz, the little HF driver sounds excellent*, and does not seem at all stressed.
I compared it to the same 1+6" drivers mounted in a regular horn stack (of similar dimensions).
The Tymphany measures worse (on axis ripple) on the crude test mule, but sounds better (nicer HF / ease of listening). I changed too many variables at once to say for sure why the test mule is better subjectively, but given that it is better, and given that I can't test every variant on the planet, this combo is what I think I will progress with.
Interesting driver, woodscrew on! 😀 The response looks nice in datasheet, impedance blip and corresponding resonance in frequency response seems to be past 20kHz.
Have you popped the driver open, what the phase plug looks like? The top end performance is probably due to smaller diaphragm and associated benefits, phase plugs always interesting though 🙂
Have you popped the driver open, what the phase plug looks like? The top end performance is probably due to smaller diaphragm and associated benefits, phase plugs always interesting though 🙂
Just tried to look. The driver breaks into 2 parts - the magnet, and everything else.
The black snout holds the diaphragm and phase plug and bug screen as one piece, so the only way to get a really good look at the phase plug would be to cut out the bug screen or saw the snout in half. I'm too lazy to order another driver, so don't want to do that 🙂
Peering through the screen does not afford a very clear view, but as far as I can tell, the phase plug appears to be of the usual concentric slit type, like the one pictured, except the middle section - the part that looks like a 3-armed starfish - is black (plastic?) while the outer ring(s) are normal looking (steel?).
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Currently trying to work out whether the horn's effective depth includes all of the snout (which is ~3cm deep).
That is, for mid drivers on the horn, the 1/4 wave cancellation distance should be the distance from the midrange tap to the bug screen + 3cm, but in practice it seems to be less simple.