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Multi-Way Conventional loudspeakers with crossovers

The POOR man's Tannoy DMT - AKA "The PM-DMT"
The POOR man's Tannoy DMT - AKA "The PM-DMT"
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Old 14th August 2018, 07:52 PM   #11
wae is offline wae  Netherlands
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Quote:
Originally Posted by Charles Darwin View Post
wae has got a pair of Tannoy DCs but this is a project which may eventually end up in a cheap, commercially available co-axial monitor if good enough and viable.
Suggesting to buy Tannoys is therefore of not much use to the OP I guess.


That being said I'd still look at 3 P-Audio drivers since they are cheap, screw-on to fit the Eminence CX and go low enough:
PA-D4155, 1.2k recommended xover, 20W, 100dB/1W;
PA-DE34S, 1.2k, 30W, 105dB;
BM-D440S Mk2, 1.5k, 108dB.

The first two retail at 29.70, the latter 47.33.
All from Blue Arran.
You right Charles, NO Tannoys this time.

Any idea what they sound like? (ANYONE?), they go low, affordable, screw-on.

kind regards.
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Old 14th August 2018, 07:57 PM   #12
wae is offline wae  Netherlands
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Originally Posted by Brett View Post
Look at the Faital coaxes. The 6 and 8" units I have are very nice.
Hey Brett, I work with Faital's, they'r OK speakers, but NOT the cheap ones here, the 8 inch is 270 euro's. May well end-up using them though, it's about 2x / 2,5 x the separate component price option I looking for.

kind regards.
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Old 14th August 2018, 08:04 PM   #13
wae is offline wae  Netherlands
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Originally Posted by nfsgame View Post
Take a look at the Monacor SP-312CX. The 10"-version is a very nice one when driven active. The 12" shouldn't be that bad either.
I will also produce an LF overview sheet, with 8", 10", 12" and 15" Coaxials.

The Monacor looks interesting, do you own them?

kind regards.
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Old 14th August 2018, 10:01 PM   #14
Charles Darwin is offline Charles Darwin  United Kingdom
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Quote:
Originally Posted by wae View Post
Any idea what they sound like?
Not a clue, mate!
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Old 14th August 2018, 10:48 PM   #15
maxlorenz is offline maxlorenz  Chile
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If I had good Tannoy substitutes I would make something like this:

YouTube

Wait! I have some

I imagine older used coaxials are better (?).

I use Beyma KX15 coaxials with 3 hands of Dammar varnish on the woofer and new improved DIY XO (a mess) and they sound good now on my Autograph (the only way to go ) enclosures.

I bought from desperation a pair of used P Audio big coaxials (the guy from commonsenseaudio said they bettered Tannoy), the P.AUDIO BM15CX38, after 10 years of hopeless anxious expectation: I didn't even have them tested yet
I guess anticipation anxiety ends when the item arrives...

If you can find a pair and your HF hearing is not what it used to be, they probably be very satisfying...

Cheers,
M.
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Old 15th August 2018, 05:52 AM   #16
nfsgame is offline nfsgame
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Quote:
Originally Posted by wae View Post

The Monacor looks interesting, do you own them?
I own the 10" and have heard the 12" shortly after finishing mine.
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Old 15th August 2018, 08:04 AM   #17
wae is offline wae  Netherlands
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Originally Posted by maxlorenz View Post

I imagine older used coaxials are better (?).

I use Beyma KX15 coaxials with 3 hands of Dammar varnish on the woofer and new improved DIY XO (a mess) and they sound good now on my Autograph (the only way to go ) enclosures.



If you can find a pair and your HF hearing is not what it used to be, they probably be very satisfying...

Cheers,
M.
Older = better, hmmm depends. We will go for NEW here

3 hands of Dammar varnish..... on a loudspeaker cone... Would you do THAT again?

Well my HF hearing is slightly but surely degrading, can't even remember during my whole life (64 now ) being capable of hearing a 20 kHz "tone".

Are the Autograph's hand build by yourself ? Look good, what's the horn shape bottom part of the enclosure ?

kind regards.
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Old 15th August 2018, 08:09 AM   #18
wae is offline wae  Netherlands
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Friend of mine with 5 cents of advise about trying to build affordable speakers.....

no No NO, you're doing this all wrong boy.... Got to make, I said, GOT TO make them darn expensive, so people expect them to be good. You SEE!!

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Old 15th August 2018, 08:23 AM   #19
wae is offline wae  Netherlands
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Originally Posted by nfsgame View Post
I own the 10" and have heard the 12" shortly after finishing mine.
Candidates ? Would you use them again if you were to start from scratch.

kind regards.
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Old 15th August 2018, 10:57 AM   #20
wae is offline wae  Netherlands
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Default DMT 215 cross-over and Where to cross what

This appears to be the cross-over for DMT 215 setup.

It will be an interesting issue, placing the drivers (distance) and since we will be using 2x 15" (or 2x 12") of which one is the Coaxial we need to think of how to use the 3 drivers (2x LF and 1 HF). ALSO, I want to have the LF's to be identical, so NOT using one Coaxial and some "other" LF to fit in. Looking at the DMT's and FSM's, they always use LF with identical characteristics. I did read an article by Tannoy stating that they started the FSM and DMT by experimenting with 2 coaxials, of which one had the HF disconnected. This way you would use 2 identical LF drivers, sound the same, behave the same, parameters and electrical behaviour to the amp the same.

In our case, using 2 coaxials and add 1 HF to one of them, we could use a 1 ⅜" bold (long enough to fill the hole) to close the screw-in gap for the HF of the other coaxial.

The coaxial is a point source by default, crossing to the HF should be related to the LF's capability on producing "HF" (more like Mid Freq. / anyway as low as possible) and the ability of the HF to play low enough. Lets call this LF the coax-LF.

Blending in the other LF (Lets call this the sub-LF) with the coax-LF is an issue (acoustical interference). My view on this: The distance between the acoustic centres of both drivers (32 cm for the 12" / 38 cm for the 15" when placed tight against each other) makes for the wavelength giving the max frequency to cross the LF's. That would be some 250 Hz point (give or take).

Am I right here? (I would expect this to be the case).

If we would go 3-way (Charles advice) this freq. will be the Low Pass of the sub-LF and the high pass of the coax-LF. Adding a low pass to the coax-LF which is the high-pass of the HF would make the principle of the filter complete.

If we would go semi 2-way (my first thought) then the coax-LF would not get a high-pass filter. The wave distance between both LF would determine the low-pass of the sub-LF to avoid the acoustical interference. So both LF's would play the low notes up until the low-pass point of the sub-LF. Gives a more solid LF, which is what we need.

Looks like the filter opts for Charles way.. (I am not a cross-over expert, learning here) but shure looks like it.

3-way summary;

sub-LF < 250Hz
coax-LF 250 - 1500 Hz
FH - > 1500 Hz

semi 2-way summary;

sub-LF < 250 HZ
coax-LF < 1500 Hz
HF > 1500 Hz

that is IF the HF would be able to go not lower than 1500, we have some that can go to 1200 Hz.

or NOT? Comments?

kind regards.
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File Type: jpeg DMT 215 cross-over.jpeg (238.7 KB, 263 views)
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