The dome midrange thread

[soundbloke]

Did they finally get rid of these oversized ferrite motor?

It is not oversized, it is the size it needs to be to achieve the performance it achieves. The amount of metalwork helps with power dissipation too, so using a smaller motor would likely cause some compromise. Having said that, ferrite magnets are not the best and offer worse distortion than even the AlNiCo magnets that came before them. Rare earth magnets offer similar potential gains.

 

[daanve]

The gigantic motor is also the reason why this beast has to be rear mounted.

In a high performance low-signature cabinet, rear mounting makes things very complicated. First it means that the baffle that the mid is mounted into is limited to 18 mm thick. All my recent baffles have been 36 mm. Second, it means that either the baffle must be removable, or the rear wall must be removable. In my view, removable cabinet walls are a major complication because it is very difficult to maintain the high structural stiffness and effective load transfer through all the bracing. We must rely on mechanical fasteners rather than adhesive bonds, and adhesive bonds are more effective.

To me, this is the major drawback of the gigantic motor on both the Volt and the ATC. The driver spacing issue is not so important to me, because I would use a 1.2x wavelength criteria, and at 3k I think it would be fine. But rear mounting is almost a non-starter for me.

For even an average woodworker, it's no problem to rear mount the driver flush with a 36mm thick front baffle. A router is your friend...
I guess you chamfer the inside edges of your woofer and midrange holes??

 

[stv]

So domes needs to have voice coils the same size of the dome itself?

They don't have to but it's one if the main features of classic mid domes, in contrast to cones:

• high power capability
• potentially high efficiency
• very good structural connection between voice coil and diaphragm

With the peerless midwoofer-domes the question is if they have any advantage compared to cones at all (besides visual appearance and eventually dispersion?).

 

[soundbloke]

They don't have to but it's one if the main features of classic mid domes, in contrast to cones:

• high power capability
• potentially high efficiency
• very good structural connection between voice coil and diaphragm

With the peerless midwoofer-domes the question is if they have any advantage compared to cones at all (besides visual appearance and eventually dispersion?).

...not forgetting no vibrating cone edge to terminate

 

[juanitox]

Appears to be 'boxer' branded, only reference I could find was here, a 10cm dome

https://audio-database.com/BOXER/speaker/t2.html
https://mjq.co.uk/equipment/boxer-t5-monitoring-system-for-sale/
Boxer T5

interesting be interesting as well To know if atc still support that larger mid dome

@soundbloke Yes, fully agree that a book can't be judged by its cover. Cheap Chinese knockoff stuff isn't going to use the same quality adhesives, materials and processes which by themselves and together will affect performance. The reputation of this ATC mid dome is proven from the many years its been in production.

You are however trading the last ounce of resolution for reliability and the double suspension has its pluses and minuses in that regard when comparing it with single suspension domes.

The main drawback of using a spider is unavoidable resonances affecting resolution and low level detail. In all sincerity, this driver's forte is its dynamic range and durability.

The Bliesma M74A/B are overall better performing drivers where it counts with superior detail and depth to the ATCs. I'd rate the D7608 better in those areas as well. The cost of the ATC is also outrageous for what you get in return and the final Achilles heel is its massive footprint, making tight CTC spacing difficult.

For these reasons alone I prefer the D7608 despite its drawbacks, which are not that significant if you don't need the last word in bandwidth or SPL. I've lived with the ATCs, Volts and ScanSpeak mids in various speakers I've owned over the years and came to the conclusion that I prefer the ScanSpeak and Bliesma (A and B version) for resolution and detail.

The D7608 is overall the smoothest and easiest to listen to for my ears. The PMCs I had with the D7608s sounded very open and transparent and had sufficient output in most mid field setup situations.

The Bliesma M74A/B are the most accurate 3" domes with the best being the Alu version. The Silk version is good too, but for the same price the M74A is a much better deal while oddly still being smoother. Its breakup peak is very easily dealt with, much more so than the M74B. I'd use the Be version with active filtering and supplement a passive HF notch to keep spurious DSP transient artifacts from exciting the breakup area.

How many liter do you charge the D7608 ?

 

[profiguy]

Is this any good?

https://www.amazon.com/dp/B01GAS8U20?ref_=cm_sw_r_apan_dp_2WFCTKAF69J85KKECPVR&language=en-US

This cheap Peerless was mentioned?
8,6 mm dome from what I can see on low resolution spec sheet.
https://www.soundimports.eu/en/peerless-by-tymphany-gbs-115n25al01-04.html

Cheers!

I ordered that mid a while ago and sent it back immediately. It wasn't put together very well as with some of the other domes made by Hivi. it's a weird hybrid of their older ferrite 3" dome. Not worth it, especially when you have to buy a few to get a close pair.

The older Morel and Dynaudio 3" domes were similar in their design. Sensitivity was relatively low, even for a mobile application. The lower xover can't go low enough to benefit from it being a larger dome.

 

[profiguy]

@juanitox I recommend between 0.7 to 1.5 ltrs with loose sheeps wool or mineral wool stuffing and modifying the rear felt layer by at least opening the smaller motor vent holes on the outer perimeter. Leaving these holes restricted by the OE felt causes a small peak just under 2k which hurts midrange clarity a little. I'll dig up my pictures for you to look at to explain it better.

 

[juanitox]

Thanks , a picture will help a lot 👍

 

[Paul Ebert]

The Bliesma M74A/B are the most accurate 3" domes with the best being the Alu version. The Silk version is good too, but for the same price the M74A is a much better deal while oddly still being smoother. Its breakup peak is very easily dealt with, much more so than the M74B. I'd use the Be version with active filtering and supplement a passive HF notch to keep spurious DSP transient artifacts from exciting the breakup area.

Have you worked with the M74P? If so, thoughts?

 

[IamJF]

Have you worked with the M74P? If so, thoughts?

Nobody here seem to have personal experience with the P version. For my projects it's not the right tool.
A friend of mine uses it and is very happy with the sound, but I could not make comparisons to S, A or B.
I'm pretty sure it delivers what Bliesma intended to do - less details as an A, more details as the S.

 

[piotr z]

Does anyone else think that much better match for T34 would be dome in size 90-100mm? Wondering if Bliesma is thinking about something like that because that would kind of fill their lineup quite nicely.

 

[IamJF]

You heared about M142? It's just not particularly cheap ...
http://www.bliesma.de/products.html

 

[piotr z]

I don't think that pairing M142 with T34 would work, but correct me if I'm wrong.

 

[IamJF]

I don't think that pairing M142 with T34 would work, but correct me if I'm wrong.

You are wrong.


no seriously - why shouldn't it work? Look at that: www.bliesma.de/M142%20Series%20Application%20Note%20AN1.pdf
They overlap for more than 1 octave.
You could even use a T25 if you really want to. It's a 142mm diameter membrane ... how often way bigger membranes are combined with 1" tweeters ...

 

[piotr z]

Application note changes a lot, thanks. Interesting option for a pricey 3 way

 

[matsurus]

Question: Wharfedale opus M 1
I have change to get this quite cheap locally, so:

Thing is, what is that middome? Vifa? Scanspeak?
Does Wharfedale make their own drivers completely or source some of those outside?

 

[IamJF]

Application note changes a lot, thanks. Interesting option for a pricey 3 way

The behaviour of M142 is very typical for drivers without back chamber. The speaker designer has to take care - as with some AMTs, Vifa 3" or when you remove back chamber of MD60N. You have to take care about the rear SPL.

On the other side - I find the backside frequency response quite interesting! Starts at 95dBSpl and rises, very wide sound distribution up to about 1,5-1,8kHz. Combined with a T34 ... and a few 12" ... You could probably even use it as horn driver ...

 

[PKAudio]

Accuton cell 6" midrange exhibits the same behavior. It is actually very nice of Bliesma to provide this App note how to arrange the rear chamber.

 

[Lojzek]

Thing is, what is that middome? Vifa? Scanspeak?
Does Wharfedale make their own drivers completely or source some of those outside?

I advise, if you really could get it quite cheap, to not give it a second thought.
Either a Scan Speak unit or something similar.

 

[IamJF]

Their mid dome drivers sit in between Accutons cell - 3" and 5". Price is also compareable. But sensitivity is way higher - I prefer the Bliesma way to do it.