Help please. Rebuilding Monito Audio MA5 crossovers as 1st DIY project

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#21
MCSmith said:
AND, last but not least; in your OPINION do you personally think that this modest model of Monitor Audio merits (sonically) this expenditure? Even though nothing esoteric or exceptional visually, it is a well made honest box with obvious and deliberate forethought.

Bottom line, with new tweeters and corresponding cap and resistor improvements, the total costs will come in at around $100 -$125 U.S. Dollars

Worth a shot?

Marshall
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Hi,

Where are you ? Sensible choices depend on what is locally available.
Sensible in my book is the cheapest that should work well for old stuff.

rgds, sreten.

I'd tend to want to use them on stands inverted, tweeters to the inside.
 
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#22
sreten said:
Hi,

Where are you ? Sensible choices depend on what is locally available.
Sensible in my book is the cheapest that should work well for old stuff.

rgds, sreten.
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Thank you for your post, but well, no kidding?!?

As far as for "what is locally available" to me, here in Northern California, unless a fellow hobbyist comes through, I may as well be on desert island in most instances when it comes to preservation and restoration of nice old things "Hi-Fi".............one of the reasons I'm here seeking assistance and hoping maybe someone has what I need short of a total replacement

This part of the world most certainly is NOT England when it come to such matters...............

Just trying to cover all the bases and keep them original if possible

I have a "wanted" ad up on "craigslist" now

Marshall
 
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#23
strawberry said:
Get 10 Watt resistors. You can keep the set up for the woofer but switch out the stuff for the tweeter. Go with 5.6 uf, inductor, 22 uf, 3.3 ohm, tweeter. Try switching the plus and minus on the tweeter and see what sounds the best. Another fix for the tweeter is to skip the 22 uf, replace with wire. See what sounds the best. This is a crossover at 3 kHz for both drivers. Look at ebay for new parts.
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I think he wants to restore it to it's original state, not transform it into a cacophony of incorrect guesswork, lol.
 
#24
MCSmith said:
Thank you for your post, but well, no kidding?!?
Marshall
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Hi,

And your point is ? What are you being smug about ?

S7 has been recommending drivers from the UK.

In the States its a completely different ball game as
to what reasonably priced tweeters are available.
Locally I mean not intercontinental shipping.

rgds, sreten.
 
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#27
system 7. Thanks for time you've taken here. I had more or less decidied to chuck my old speakers but your point about the quality if the cabinet and the B200 and a lower crossover made me change my mind. I;ve been reading about the P10 Tysen, where they use a cone tweeter and crossver at 300-500 HZ, if you were doing this with the MA5s, what tweeter and crossover point would you go for with the B200s?
Thanks
 
#28
getaliife said:
system 7. Thanks for time you've taken here. I had more or less decided to chuck my old speakers but your point about the quality of the cabinet and the B200 and a lower crossover made me change my mind. I've been reading about the P10 Tysen, where they use a cone tweeter and crossover at 300-500 HZ, if you were doing this with the MA5s, what tweeter and crossover point would you go for with the B200s?
Thanks
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You'll appreciate I was talking about just restoring the MA5's here. New tweeters, fixing the fried resistors and a bit of L-Pad tweeter attenuation to match it all up. 🙂

An externally hosted image should be here but it was not working when we last tested it.


You are talking about a very radical redesign with a Fostex FF85WK it seems. FWIW, it's Planet_10's opinion that that particular Fostex is a pretty good tweeter in it own right. Do you know which SP number KEF B200 you have? What is the size of the tweeter hole cutout in the baffle? Coincidentally, Planet_10 (aka Dave) likes the KEF, because this is his website below:

TL Links

The benefit of using a separate bass unit with Fostex FR drivers is you spare the fullrange from big driver excursion which tends to make it non-linear and muddled with complex bassy music. But you'll need a separate enclosure for the Fostex, which could sit on top of the bass. It's doable if the sensitivities match, and the crossover can be a simple one somewhere between 300 and 1500Hz. It could be win-win, because you are then operating the KEF B200 below its breakup mode (>1.5kHz) too. 🙂

Since you like cone tweeters, you might also consider a little bit of fun I've been toying with in two and three way configurations:
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories

Cheap as chips, those Visaton cone drivers! About £10.
 
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#29
STeve
Had some time this w/e. Decided to check the B200 SP1014s by reinstalling them in the MA5s, without crossovers, disconnected tweeters in place to seal the cabinets . I was very surpriosed how lousy they sounded, very thin and with echo. Not good I was thinking - Would that be what you would expect? Then I experimented with foobar to cut out higher frequencies, and was able to hear lower bass than with some small 2 way speakers. Maybe OK now. Then biwired a combo, Kef for bass and small bookshelfs HF, better but there was a gap in the mid frequencies - higher crossover in the bookshelves I suppose.

What do you think about the poor sound from the MA5s Kef units only runing full range. Does in sound like they're blown ot would you think it's worth persevering?
 
#30
No don't worry. Most bare woofers sound horrible without the bafflestep inductor. It rolls off the midrange and gets a more realistic sound. The added series inductor sounds like bass boost, or what we used to call the loudness control. 🙂

You'll also improve the bare driver by turning up the bass with a tone control. This is worth persevering with. The KEF B200 is a nice unit, and the cabinet is probably way better than anything you would buy these days. You still haven't told me the size of the tweeter hole or the SP number of the bass unit, so I'm limited in suggesting options.

Some sort of crossover schematic is helpful too.

Oh wait. SP 1014. Can do something with that! LOL
http://www.t-linespeakers.org/drivers/b200.html

Qts of 0.51, so it's a 20-30L closed box driver, not suitable for reflex.
 
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#31
Steve and getaliife,
There is this "new" driver you must be interested in the Visaton B 80 8 OHM. Looks promising on paper.
"8 cm (3.3") high-end full-range loudspeaker with excellent balanced response characteristics. Due to perfect accordance of the coated paper cone, the rear ventilated damper and the phase plug, as well as the strong and lightweight neodymium magnet, an extremely well-balanced frequency response with very low harmonic distortion and lowest possible mechanical losses comes into being. The B 80 8 OHM is ideal for small high-end shelf speakers or as a mid-high-range unit in high-end multi-way speakers."
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
 

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