In Martin Colloms book on High Performance Loudspeakers he discusses dome mids in a pretty objective manner with pros and cons listed. I wont quote in full but he observes that they can be v.good. But he does make an interesting point about angular dispersion. If we start with a size of 2", which is probably a popular size for a dome, the dispersion may well be worse than a cone driver as a cone will tend towards radiating from approx if 1" (or less) at the apex as the frequency rises while the dome will tend to radiate from twice that area despite being nominally smaller than most cone-mids.
Alan- by ring-radiator, do you mean that the tip may not function as speedily as the edge and almost act as a bending-wave driver to emulate a slight ring-radiator effect?
That's the only way I can call domes ring radiators, since the tip is not mounted physically in space like the SB29, XT25, and other variants.
Later,
Wolf
That's the only way I can call domes ring radiators, since the tip is not mounted physically in space like the SB29, XT25, and other variants.
Later,
Wolf
Last edited:
Have to DIY then
You might want to apply foam to the parallel surfaces above and below the tweeter to control standing waves. Shaping the foam into deep V shapes, with the tips of the Vs almost touching the tweeter dome, would work a treat.
Yeah, his is an excellent book. I wish I had it too, but it is rather expensive. I have however read portions of it.
From what I know about dome mids, at some frequency the circumference of the dome begins to radiate out of sync with the apex. It mechanically decouples due to the dome flexing and bending, etc, that is when the dome mid no longer acts like a point source.
Last edited:
Has anyone checked Beyma 2,5" dome? MC115 - Beyma midrange dome 25W 600-12.5 kHz 8 Ohm - Europe Audio
I was wondering if ordinary 6,5"+1" 2-way speakers mid driver is moving too much and modulating higher frequencies because it is playing bass also. Yes, cone movement is high. Still, is nothing gained if speaker is turned into 3-way using 2,5" dome in area, say 1200 - 5000 Hz? 2,5" dome has only 15% of the area of 6,5" so dome is also "moving" a lot even if it is mid driver, 'cos it is so small.
I was wondering if ordinary 6,5"+1" 2-way speakers mid driver is moving too much and modulating higher frequencies because it is playing bass also. Yes, cone movement is high. Still, is nothing gained if speaker is turned into 3-way using 2,5" dome in area, say 1200 - 5000 Hz? 2,5" dome has only 15% of the area of 6,5" so dome is also "moving" a lot even if it is mid driver, 'cos it is so small.
I have seen some where a test with the beyma a obsolete 2"monacor titanium mid dome and a other I do not know any more, what I can remember that the THD raises fast of the beyma at low frequency XO.
And zaph tested the dayton titanium dome very good . Morel has some a nice one's. Also HIVIRESEARCH/SWANS has several 2"ones. Scan speak and Tangband have 3"dome's.
Ciare has also nice dome's see this topic.
http://www.diyaudio.com/forums/multi-way/183727-ciare-design-idea.html
Seems that you are usually designing speaker whose midrange carries most of load? 6 octaves for small fullrange driver. I think you not sign design idea where one driver should cover around 3 octaves?
What was low XO? I think if there is speakers which 1" dome is crossed around 1,5 kHz 3rd order, must 2,5" dome handle 1,2 kHz XO quite good.
---
It is true that 2-3" domes seem to be more like big tweeter than mid driver (if midrange driver is understood so it could cover some lower mids or even upper bass).
Last edited:
25 years ago now 3" dome midranges were all over the place from all sorts of mfrs... try to find one today!
But if you want a dome mid like that you could "cheat" and take a nice dustcap off a big woofer and glue it to the edge of a properly sized cone midrange!
Of course the "thing" with the dome mids was that the VC was the diameter of the outside of the dome.
Thing of it is that I need to replace a 3" dome mid in a nice old 3 way with something, and I'm having trouble finding a decent cone driver to drop in the hole - and I have latitude as far as size, I can go up to a 5.25" mid - the problem is price vs. performance. I'm not psyched to spend $50 on a mid driver that is not really really excellent AND has decent sensitivity (>90 dB). As in where have all the decent and inexpensive mid drivers gone, forget about finding a 3" dome to fill the opening!
_-_-bear
PS. as you can likely tell I have not been building speakers now for a while... hee hee.
But if you want a dome mid like that you could "cheat" and take a nice dustcap off a big woofer and glue it to the edge of a properly sized cone midrange!
Of course the "thing" with the dome mids was that the VC was the diameter of the outside of the dome.
Thing of it is that I need to replace a 3" dome mid in a nice old 3 way with something, and I'm having trouble finding a decent cone driver to drop in the hole - and I have latitude as far as size, I can go up to a 5.25" mid - the problem is price vs. performance. I'm not psyched to spend $50 on a mid driver that is not really really excellent AND has decent sensitivity (>90 dB). As in where have all the decent and inexpensive mid drivers gone, forget about finding a 3" dome to fill the opening!
_-_-bear
PS. as you can likely tell I have not been building speakers now for a while... hee hee.
Hi Wolf
Would you mind sharing your views on the Dayton RS52? I have a pair which I have yet to use. Would be nice to know what I'm up against.
Hi bear
I'm building a 8" 3-way with a VIFA 3" Dome (D75MX) right now. It may be what you're looking for. I believe they are no longer in production but they do pop up on ebay once in a while.
25 years ago now 3" dome midranges were all over the place from all sorts of mfrs... try to find one today!
But if you want a dome mid like that you could "cheat" and take a nice dustcap off a big woofer and glue it to the edge of a properly sized cone midrange!
Of course the "thing" with the dome mids was that the VC was the diameter of the outside of the dome.
Thing of it is that I need to replace a 3" dome mid in a nice old 3 way with something, and I'm having trouble finding a decent cone driver to drop in the hole - and I have latitude as far as size, I can go up to a 5.25" mid - the problem is price vs. performance. I'm not psyched to spend $50 on a mid driver that is not really really excellent AND has decent sensitivity (>90 dB). As in where have all the decent and inexpensive mid drivers gone, forget about finding a 3" dome to fill the opening!
_-_-bear
PS. as you can likely tell I have not been building speakers now for a while... hee hee.
Is 3" dome 92dB 1Wmtr enough? http://www.scan-speak.dk/datasheet/pdf/d7608-920010.pdf
Save on the tweeter low and mid qaulity is of most importance.at what price?
Madisound wants ~100$ USD... too much for this project.
_-_-bear
MFG SWAG
Cannot implement a dual suspension (surround-spider) system easily that supports the larger excursions required while mitigating the modal rocking that can occur at lower frequencies. Competing cone driver of same performance quality typically cost less to make.
Regards,
WHG
That's the entire question!
Cannot implement a dual suspension (surround-spider) system easily that supports the larger excursions required while mitigating the modal rocking that can occur at lower frequencies. Competing cone driver of same performance quality typically cost less to make.
Regards,
WHG
Disagree completely - a rotten tweeter and you can throw the thing in the garbage immediately. Besides these have old Panasonic Leaf Ribbons that work fine... I need mids. They had 3" domes, but they died a sad death, the death of time. It has 10" woofers and 15" PRs, also dead of foam rot and being played that way (ha ha)... this is a 1970s speaker system called the "Pentagram"... hardly state of the art, but the cabinet was made by a first class cabinet maker, it's a three way, and makes for a good sounding system. It needs refurb, thus I seek a wideband mid to fill the physical hole and the acoustical hole as well!
Where's a good $25 midrange driver when you need it??
_-_-bear
Disagree completely - a rotten tweeter and you can throw the thing in the garbage immediately. Besides these have old Panasonic Leaf Ribbons that work fine... I need mids. They had 3" domes, but they died a sad death, the death of time. It has 10" woofers and 15" PRs, also dead of foam rot and being played that way (ha ha)... this is a 1970s speaker system called the "Pentagram"... hardly state of the art, but the cabinet was made by a first class cabinet maker, it's a three way, and makes for a good sounding system. It needs refurb, thus I seek a wideband mid to fill the physical hole and the acoustical hole as well!
Where's a good $25 midrange driver when you need it??
_-_-bear
ALTEC CF404-8A.. you should be able to purchase it for about 20 US.
92 dB at what frequency? Hardly 91 dB/W and at very narrow bandwidth.
Very strange dispersion that has.
Beaming is much stronger than in ordinary 4,5" cone mid.So what pros of dome mid? Lesser beaming in mids than large sensitive cone and usually more sensitive than small cone (that does not beam that much)? Seems that directivity in transition from woofer to mid (700 ---> 3000 Hz) is always getting bigger which narrows listening area.
Someone reported that 2,5" mid dome played wonderfull wide image and piano plays in room, not between/in speakers. Does that come from wide dispersion?
Someone reported that 2,5" mid dome played wonderfull wide image and piano plays in room, not between/in speakers. Does that come from wide dispersion?
In fact a cone is some kind of inverted dome when you look at it.92 dB at what frequency? Hardly 91 dB/W and at very narrow bandwidth.
Very strange dispersion that has.
You can not hear wide dispersion. You can hear very small dispersion on your sweet spot. That is why I think you do not need very wide dispersion but a equal dispersion at a limited angle to prevent unwanted reflections.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.