Dayton DC28f discrepancy?

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#21
silver, micro means 1 millionth of something. 345m/s equals to 345/1,000,000 m/us = 0.000345 m/us, for 22.77 us= 0.007855m=0.7855 cm

thump, people have a clue alright, you're just not willing to converse.


edit: silver, your calculus in post #19 is correct on the left side, only the result was a glitch
 
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#24
Lojzek said:
thump, people have a clue alright, you're just not willing to converse.
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No, they don't. Unless you are the person that did the actual measurement AND are aware of what went wrong, (and for some perverse reason, didn't care to correct it) you don't know.

I was never interested in why it was wrong, as everyone else that has commented in MY thread has seemed to try to explain. 6-7db can NOT be explained by any answer given so far that any semi-competent person doing the measurements wouldn't catch. Even PE said they weren't sure, hence my calling all of this here "speculation". If the source isn't sure...............

All I cared about was getting the .frd file correct and the easiest answer to that was a remeasure of the Dayton DC28F-8 driver, which PE has done.

You wanted conversation, Lojzek. Well, there you have it.
 
#27
THUMP LUMP said:
"Silverprout" made an assumption and everyone else (particularly you) went with it. Even AFTER I had told you what PE said when you asked.
This wasn't a "conversation" problem but an unwillingness to listen to what I DID say.
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😉 Sorry i can't resist... but i must say that your avatar is scary and it has an effect on what you've wrote in front of it (it's stupid but human)
Now i'm not afraid anymore 😀
 
#28
Thump, thanks for asking this question. Very helpful since I'm using this tweeter as well.

Looking at the impedance graph, would you use a zobel network to smooth out the humps? Would you use a zobel network on a tweeter?

Thanks,

Vince
 
#29
Actually, Silverprout, I believe it was your link that drove those that followed down the path they went.

vdi, attached is the Dayton BR-1 modded MurphyBlaster Xover. The BR-1 uses the Dayton DC28F tweet and a DC160-8 woofer. This is just an example. How you will need to tune the xover for the DC28F will depend on what you want out of it as well as what woofer you are using with it.
 

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#32
THUMP LUMP said:
Curious at this. PE specs put the SPL at 89db @ 1w/1m where as the FRD graph and FRD file put the SPL around 95+, depending on were you look. What gives?
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I use this tweeter and I like it. However, it is not efficient and I'm more likely to believe the 89db curves. When I measure it against a claimed 90db woofer its always 2 db lower although in the higher freq range of course. I don't have a calibrated mic or anechoic chamber so its a relative measurement.
 
#35
system7 said:
Grasshopper, you have much to learn... :hypno2:

Robin Marshall: A Modicum of Genius | Stereophile.com

Soft-domes produce a facsimile of music, because your Brain makes a correction. It's not the real thing. Once the centre of the dome goes into breakup above 7kHz, they have just lost it completely. IMO. 😀
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So........ you're one of those. You let specs and measurement make up your mind as to how something sounds and not your ears.

OK........Pick another tweeter, UNDER $20.00 (U.S. Dollars and not that stuff you use), that sounds better.

I suppose you also think that everyone should listen to one type of music because it's, in your opinion, sonically correct?

I'll ignore that fact that you obviously missed were I said "For an inexpensive tweeter"

Just wondering.....have you ever come close to drowning when it rains????
 
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#37
Actually, Thump Lump, soft domes measure beautifully. Except, if you are really measuring the right thing, on the waterfall of stored energy and phase. Just that they sound like dreck, IMO. Spitty and overly bright. The Yamaha NS-10 was a popular monitor, because it represented what most people were listening to.

I did a rather sophisticated Acoustic Butterworth filter for my Morel CAT 298 soft dome. It still made my ears bleed! 😱

More recently I listened to Robin Marshall and tried cone tweeters, which cost about $10. Here the Monacor HT-22. Some dispersion issues, but very musical. And I could do something about the very top end dispersion with a supertweeter. I don't mind mylar domes either.

I'm also happy enough with metal domes too. SB Acoustics and Vifa Ring-radiators might be a future project. They have theoretical strengths, but were not around in Robin's day. Who knows about Beryllium...

The fact is, with soft-domes, is you always spend a lot of time reducing their output to make them bearable. Well, maybe there's a better way. Ditch them altogether. But don't let me stop you wasting time on them. 🙂
 

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#38
system7 said:
Grasshopper, you have much to learn... :hypno2:

Robin Marshall: A Modicum of Genius | Stereophile.com

Soft-domes produce a facsimile of music, because your Brain makes a correction. It's not the real thing. Once the centre of the dome goes into breakup above 7kHz, they have just lost it completely. IMO. 😀
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No need to be condescending or snide. It won't help or further your case.

Dome breakup and resonances are certainly there for anything mechanical. The question is, "do you have an independant test report for this DC28F". Secondly, is it important to liking the tweeter when you listen to it.

I have many tweeters : silk soft dome, poly soft dome, Al-Dome, and Ti-Dome tweeters and I prefer the soft dome.

As for the article link. Its just an interview with a guy who claims to have invented the metal dome tweeter arguing as to why it's superior to soft domes. Somewhat biased. I'm not from Missouri, but I certainly understand them.
 
#39
Don, whatever I say to Thump Lump, I'm going to come over as more polite than him. N'est pas? 😀

Most people wouldn't know a phase plot from a hole in the ground IME, though they tell me a lot about stored energy. But here's a waterfall by Troels Gravesen of a 3" soft dome ATC mid. Some horrors there above 4.5kHz. A smaller 1.125" tweeter is going to do the same thing at a higher frequency.

With science, it is best to leave your ego outside the door. Because the science always wins. 😎
 

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#40
system7 said:
Don, whatever I say to Thump Lump, I'm going to come over as more polite than him. N'est pas? 😀

Most people wouldn't know a phase plot from a hole in the ground IME, though they tell me a lot about stored energy. But here's a waterfall by Troels Gravesen of a 3" soft dome ATC mid. Some horrors there above 4.5kHz. A smaller 1.125" tweeter is going to do the same thing at a higher frequency.

With science, it is best to leave your ego outside the door. Because the science always wins. 😎
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I'm still waiting for science to appear.

We are talking about this particular 28mm soft dome. Do you have a test report? I'm sure all physical devices have mechanical resonances. Are they relevant? Even in the same class of device there can be huge variation in performance. Presenting one graph of a 75mm soft dome and claiming it is relevant to all soft domes of all sizes everywhere on the planet is not science. You are extrapolating from a single data point.

I have an open mind, I'm just asking for proof, and I have not seen it.
 
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