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Multi-Way Conventional loudspeakers with crossovers

Classic monitor designs?
Classic monitor designs?
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Old 5th August 2017, 05:19 PM   #511
exurbia is offline exurbia  Australia
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If I didn't have to p#ss fa!t around cropping pictures I would put some up of my krixes.
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Old 5th August 2017, 10:55 PM   #512
Ro808 is offline Ro808  Netherlands
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Quote:
Originally Posted by wesayso View Post
I want it as perfect as I can get it, with a touch of personal preference
Obviously, I am not talking about major deviations from "the ideal", but something along the lines of Troels' tiny XO tweaks by playing around with different resistor values.
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Old 5th August 2017, 11:05 PM   #513
Ro808 is offline Ro808  Netherlands
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Quote:
Originally Posted by exurbia View Post
If I didn't have to p#ss fa!t around cropping pictures I would put some up of my krixes.
Are you familiar with this?

It's a kind of 'Photoshop ultra light' and allows you to easily convert formats, resize etc.

Last edited by Ro808; 5th August 2017 at 11:18 PM.
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Old 5th August 2017, 11:14 PM   #514
Bigun is offline Bigun  Canada
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Classic monitor designs?
Quote:
Originally Posted by Ro808 View Post
Obviously, I am not talking about major deviations from "the ideal", but something along the lines of Troels' tiny XO tweaks by playing around with different resistor values.
I'd rather do that in the drive electronics, somehow that seems a more appropriate place as you can control things at smaller power levels than in the XO.
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Old 13th August 2017, 03:32 AM   #515
system7 is offline system7  United Kingdom
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This is one of my backburner projects, which I have been playing around with.

This old Monitor Audio MA7 12L reflex box:

Click the image to open in full size.

It seems to have improved with a bit of run-in. I'm not surprised, because electrolytic capacitors that get no voltage lose their insulating layer over a few months. It's a chemical thing IIRC.

The simulation is not exact, but close enough to tell us what goes on. It, like the classic BBC LS3/5A is a BW3 design. You really ought to know about BW3 in a World that seems obsessed with LR2 and LR4. See, 90 degree BW3 phase is a constant power filter. You can get impedance exactly flat with a bit of effort.

And it sounds good all round the room. No deep nulls above and below axis.

I'm growing to enjoy this paper bass 5" speaker in the near field of a small room. The bass is really very good. And my modelling suggests it (third Order) might work well with the notoriously difficult 6" bass. I have very little time for soft domes, but those old 3/4" mylar tweeters work well. They just don't seem to make 'em any more.

Couple of good driver selections by Troels, not that I'd use his filter ideas. This idea is better, IMO. Classic monitor designs?

Click the image to open in full size.

Peerless HDS PPB 830860
Vifa PL14WJ-
Attached Images
File Type: jpg Monitor Audio MA7.jpg (70.9 KB, 1218 views)
File Type: png MA7 Phase Response.PNG (10.8 KB, 371 views)
File Type: png MA7 Directional Response.PNG (32.0 KB, 368 views)
File Type: png Third Order Theoretical values 3kHz.PNG (18.6 KB, 63 views)
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Last edited by system7; 13th August 2017 at 03:35 AM.
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Old 4th September 2017, 09:58 PM   #516
Ro808 is offline Ro808  Netherlands
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Quote:
Originally Posted by system7 View Post
I have very little time for soft domes, but those old 3/4" mylar tweeters work well.
Steve, what is wrong with a proper soft (i.e. silk) dome?

Here's an intering paper on light metals and
alloys, ceramics, CVD diamond, and/or composite materials for cone, dome and surround applications.
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Old 5th September 2017, 01:30 AM   #517
system7 is offline system7  United Kingdom
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Since 80-90% of the World's speakers have soft domes, I'd possibly offend a lot of people by suggesting there is a better way of doing things. Nobody wants to hear this sort of thing.

But here's a history lesson. 50 years ago or so, most speakers used 2-3" cone tweeters. And very fine they sounded if implemented well. But they fell off badly off-axis. Very directional, you see. Enter the 1" soft-dome, mainly by Philips. Great dispersion off-axis. But not so musical. Not so engaging into the audio-illusion of the live performance.

I read Robin Marshall years back on rigid metal domes versus soft-domes: Robin Marshall: A Modicum of Genius | Stereophile.com

The problem with soft-domes, IMO, is the centre of the VERY floppy soft-dome plays different tunes from the edge. Sometimes it is moving in the opposite direction from the edge. This, IMO, ADDS distortion, whereas some other types simply dip into silence due to more damping applied.

Back in Robin Marshall's day, ring-radiators were unheard of, but pinning the uncontrolled soft-dome centre seems like a plan if you avoid the more rigid metal types. We now have Vifa XT25 and SB Acoustics soft material ring-radiators, below.

I am forming some theories these days. I think flat impedance is a good thing, especially for cheap amplifiers. And I have built a lot of exotic amplifiers, so I'm no fool about how difficult they can be to keep stable with certain electrical loads. I think BW3 is a good thing that musical types like, who know how live music sounds.

Classic monitors is about the tested ideas that work well. Here's the waterfall plot of a very high-end Morel soft-dome. A lot of nasties there, IMO. I've never had much luck with my similar soft-dome Morel CAT298 tweeters. Everything else worked better. Monacor HT-22/8 Cones and Visaton DT94 Mylar and aluminium SEAS 19 TAF/G included.
Attached Images
File Type: jpg SB Acoustics SB29RDCN.JPG (49.9 KB, 59 views)
File Type: jpg Morel Soft Dome Waterfall.JPG (45.4 KB, 338 views)
File Type: jpg system7_speaker_picture.jpg (84.5 KB, 56 views)
File Type: jpg Modified_MA-R300MD_HT22-8.jpg (79.0 KB, 35 views)
File Type: jpg Sony E44 Modified.jpg (72.5 KB, 160 views)
File Type: jpg Monitor Audio R300-MD.JPG (35.2 KB, 37 views)
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Last edited by system7; 5th September 2017 at 01:40 AM.
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Old 5th September 2017, 01:26 PM   #518
Alex M is offline Alex M  Europe
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Surely the problem with soft domes is much the same as with midrange drivers, which are mostly used well outside their pistonic range too, and dealing with cone breakup modes is accepted as being critical to clean performance.

That Morel is obviously poorly designed! Here is a waterfall plot (not my measurement) for the SEAS 27TFFC soft dome I used in Troels' 3-Way Classics:

Click the image to open in full size.

MUCH cleaner than the Morel.

Alex
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Old 5th September 2017, 02:15 PM   #519
Zvu is offline Zvu  Serbia
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Here is waterfall for Morel MDT32s from the same guy:

Click the image to open in full size.
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Old 5th September 2017, 03:19 PM   #520
boswald is offline boswald  United States
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Classic monitor designs?
Look at the time scales. Bad comparison.
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