NEWBIE: Seeking 2 or 3 way SEALED DIY project!

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Here is a 4-ohm 3-way TMWW design which meets your initial goals of sealed, 50-30kHz, >90db sensitivity.

Tweeter: Satori TW29RN-4
Midrange: Satori MR16P-4
Woofers: 2* SB23NRX45-8
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This thread has TMW ideas for using a single sealed 4cuft volume for the 12" SB34NRX75-6 which delivers -F3 ~35Hz with SPL ~87-88db including a modest baffle step. You can build a shorter version of Zaph's MTM-W 12.3 cabinet for my TMW.

Zaph|Audio SB12.3, slight redesign
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Hi Tony,
I am prepared to make a complete speaker design for you on paper. I use Leap for my designs and I have a lot of experience with it. You can choose for a passive or active system. I will do it for free, it is always interesting to see a practical realization of something which is designed on paper. [/url].
Paul

Paul understands that it would be difficult to find a proven kit meeting your stated requirements.
 

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Tony

For the Audio Note AN-E I find:

Dimensions: (Height, Width, Depth) 790 x 360 x 270mm (31" x 14" x 10.5").

That is an internal netto volume of about 50L.
Is that about the maximum enclosure size you have in mind?


Paul

Thanks for sticking with me on this.

Ideally, an internal volume of: -
(Height, Width, Depth) 540mm x 270mm x 230mm

This matches a favorite old sealed German speaker that I have been unable to repair.
(Blown tweeters that appear to be like a hen's teeth!)
 
Big Woop …. For Big Woof
--A sealed 18” woofer like the $210 Peavey LoRider18 in an 8cuft sealed volume has –F3 ~45Hz with 95db sensitivity, AND -F3=32Hz with the port open.
--A sealed 12” woofer like the $175 SB34NRX75-6 in a 4cuft sealed volume has –F3 ~35Hz with 87db sensitivity, AND -F3=26Hz with the port open.
 

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MY MOTIVATION:

The MAGNAT ALL-RIBBON 6 Speakers (below) are our all-time favourite speakers at home.

Specs for this late 1980s West German speaker couldn't be more impressive: -
93-96dB Sensitivity
08-ohm Nominal Impedance
28Hz - 34kHz Frequency Range
Sealed Cabinet

But the blown tweeters are like Rocking-horse Dung these days and seem to be impossible to repair this tweeter to original spec - which is VERY extended with no harshness at all.

Being unable to repair or replace these tweeters has been the driving force behind trying a kitset build. We were hoping to build something similar, including some new stands.

I thought it would be much easier to find something similar in performance and appearance.
(I was wrong...)

:(:(:(
 

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The Magnat All- Ribbon 6 have a sensitivity of 1.2W for 96dB. Suppose the woofer impedance is 8 Ohm, then the sensitivity is about 95dB at 2.83Vrms. To realize 95dB down to 28Hz in full space you need a woofer driver with a 101dB sensitivity at 2.83Vrms, not that easy to find such one. I have some doubts about this sensitivity specification down to 28Hz…

With internal dimensions (Height, Width, Depth) 540mm x 270mm x 230mm, the netto volume is 34L. For a 3-way, a split up of about 28L for a woofer and 6L for a midrange is an option.
Using such volumes, a 2 way with a 8 inch woofer or a 3-way with a 8inch woofer and a 4 to 5 inch midrange is possible.

To reproduce the Magnat sound, I think a 3-way with a small midrange is more recommended.
Also the Yamaha NS-1000 have such enclosure shape. But they are a little larger and have a 12 inch woofer. And they are designed as bookshelf. I like their sound.
 
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Paul

Your knowledge and logic are so very impressive.

I've never heard the YAMAHA NS1000 speakers, buy have heard of them, of course.

The MAGNAT ALL-RIBBON 6 specifications state sensitivity of 1.0W for 96dB.
(See image below...)

I also own a pair of KLIPSCH RP-160M, rated by KLIPSCH as 96dB @ 2.83V / 1m.

I can attest to the MAGNAT ALL-RIBBON 6 and the KLIPSCH RP-160M as having identical in room overall efficiency, having driven them in Tandem - with the KLIPSCH on one channel and the MAGNAT on the other. The imaging was perfectly centered and the volume attenuation identical to my ears.

It is possible that both KLIPSCH and MAGNAT have over-stated these specs, which brings me to another completed home test.

I have also run the KLIPSCH RP-160M and a brand-wew (demo pair) of KLIPSCH HERESY III in tandem - one speaker per channel on the same amp - and again the overall in-room efficiency was identical.
(To our ears, the RP-160M easily delivered a far superior sonic performance in every area BTW...)

Worth noting that the KLIPSCH HERESY III is rated by KLIPSCH as 99dB @ 2.83V / 1m.
(Possibility another over-rating...)

All very interesting.

The upshot of all this is... Good as the rear ported KLIPSCH RP160M is, with its sealed cabinet bass style, the MAGNAT ALL-RIBBON 6 still wins the day to our ears.

Do you think there is there a chance we could find a suitable tweeter to repair our beloved MAGNATS?
 

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Tony

Maybe the Magnat sensitivity specification is made as a bookshelf speaker. It means that the sensitivity is specified in a half space environment and not in full space ( =anechoic room). Comparing half and full space sensitivity, for low and low medium frequencies the level in full space is about 6dB lower. Which should mean that for the Magnat the sensitivity is around 90dB for low frequencies in full space. That should be more realistic for this size of speaker and drivers.

Anyway I think you have to choose again for a high sensitivity speaker to replace your Magnat. I have also the experience that high efficiency speakers have that easy playing sound which is so nice to hear. The same experience with big high efficiency horn systems. Maybe give it a try to make a new high efficiency speaker. You can have all my support and I think also of other forum members.

If you like to do that, we first have to find some interesting high efficiency drivers. Suppose you like to create a sensitivity of 90 dB or higher in full space, we have to find a woofer with a sensitivity of 96dB minimum. And a midrange around 93dB and a tweeter of minimum 90dB. We can make the sensitivity as high as the drivers can realize.

Concerning the damaged tweeters of the Magnats. It is like Lojzek is telling also, sure there are other tweeters for replacement. The problem is the implementation, especially the X-over adaptation. If you are able to do some acoustical SPL measurements and electrical impedance and transfer measurements I can give you the support to realize this.

Paul
 
There may be a chance to repair the original tweeter. Manufacturer states aluminum flat wire (ribbon) and I wonder what the conection to tweeter terminal looks like. May be just a electrical continuity issue. I wonder what the schematic is and what the crossover looks like.
 
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If you really love those speakers your best bet is to get a microphone, learn to measure, and give us (esp. Paul) the data. Luckily you still have one good tweeter, so a pair of new tweeters can be set up to sound the way the originals were set up to sound.

I have been able to repair many tweeters for Allisons(I have Ones), but they too are becoming unobtanium(now they are merely inaffordium). So I am working on a current replacement with modern parts. So you know I "feel your pain".

Stick with it, if you love them. We'll help.

Yours in liking what we like, David
 
I have some naim arrivas in a second system - they sound exactly what you want - totally sealed and very punchy. I think drivers are stock vifa models though this needs looking into. if you could get the exact drivers (and the circuit) this could be a good design to copy - sloping front baffle and separate inner enclosures for bass + mid (both 6'' drivers). they are cheap as chips 2nd hand (in uk anyway) maybe a refurbish (re-veneer?) and xover upgrade is an option if you find a 2nd hand pair?
 
Troels did a sealed bass design recently using a plate amp for bass letting you use your valve amps on the mid/tweeter....best of both worlds, maybe. :)

MUN17-3W

The used Hypex plate amplifier in that project has a latency of 1.12ms for the analogue inputs, because of the digital processing. So the bass is delayed w.r.t. midrange and tweeter. You can compensate for a part in the frequency domain by changing filter slopes, but in the time domain the bass will always come too late. I don't say it isn't good, but I don't like it for a crossover frequency at 200Hz.
A friend of me did a test with a miniDSP in a digital 3-way by delaying the woofer 1ms. He said he could hear the difference as a less focussed, more enlarged sound image. In my opinion the timing will be affected in such concept. I think it is better to make it full analog or full digital, not mixed.
 
Concerning the damaged tweeters of the Magnats. It is like Lojzek is telling also, sure there are other tweeters for replacement. The problem is the implementation, especially the X-over adaptation. If you are able to do some acoustical SPL measurements and electrical impedance and transfer measurements I can give you the support to realize this.
Paul

Guys

I think this is a very sensible step forward to us. Failing success in this endeavor, we will attack a new build.
Frankly, I never would have guessed that I could expect such support from strangers on a forum. We are quite overwhelmed by your generosity.
So, sincere thanks again, to Paul, Lojzek, Boswald, LineSource and others. What an A-Team!

:firefite::firefite::superman::firefite::firefite:


Sometime soon, I will post very clear photos of that faulty MAGNAT tweeter and the inner area that appears to have gone 'open' circuit.
(It seems that the wire connecting the tweeter to the internal speaker cabling is thinner than a cat's whisker - not a flat ribbon wire BTW - so I can imagine that a well-intentioned blob of solder is probably not going to help restore the frequency extension that these tweeters excel at...)

So, photos to come.


(One more thought... Should I start a new thread entitled "MAGNAT ALL-RIBBON 6 TWEETER REPAIR OR REPLACE..."?)
:idea:
 
Once I had to to repair 2 open circuit midrange units and both had the same fault, hidden in the circled area. So I disolved the glue and started looking for the point of a broken connection. Before that I scraped the enamel lightly at the spot that arrow shows to make sure which terminal was faulty and if the voice coil still measures normal DC resistance.


If this was the case with magnat tweeter, that would make it even harder to repair but what has got one to lose? Good luck, I am confident that you (we) will have this sorted one way or the other.
 

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Confirmed with thanks Paul.

Let's put this thread on the back-burner for the moment and I will start a new thread for the MAGNAT ALL-RIBBON 6 TWEETER REPAIR OR REPLACE, including all of the salient information to date.

(To be continued... Perhaps. :snail::snail::snail: )

I think you could replace the tweeter, quicker than probably building a new proven design. You might be able to even improve the sound by replacing old capacitors with more accurate values (they wander over time).

It depends on your woodworking skills in being able to modify the existing baffle for the new tweeter.

Here's my setup to measure - what it cost.
PC - $25 (an old lenovo off trademe). You might be able to get away with a USB soundcard (pulse response will vary) but you can get around that. I won't describe that here

Microphone - I use a Behringer ECM8000 - it cost about $100 from memory. You can self calibrate - I can show you how (or do it for you if you send it to wellington)

A balanced XLR cable (to connect mic to preamp) ~ $30?

A microphone preamp - I found one on Trade me for about $100 - with balanced XLR connector

A jig - this connects the mic pre-amp. You can just make this up yourself. Mine comprises a plastic box with a few RCA connectors and speaker binding terminals, so I can swap in and out stuff

Software - I use speaker workshop (free) for xover sim and measurement. I also use Bagby' and Laub's excellent spreadsheet tools

+... new tweeters.

If you just want to fix your existing speakers, nothing more... someone in Auckland must have the above setup.

If however you might get into speaker DIY - then the above will pay off in the long run and you'll be able to tweak / tune / measure and optimise your refurbished speakers until just how you like them.
 
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