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-   -   Martello Fr88ex (http://www.diyaudio.com/forums/full-range/216870-martello-fr88ex.html)

awqawq 27th July 2012 11:18 AM

Martello Fr88ex
 
Hello
I have read all the threads about Martello Fr88ex and decided to build one my self. Right now I building a carbord modell but was wondering, is the model outdated? Are there any better elements right now? (2012)

2 x Fr88ex costs 100$ in Sweden.

If not what kind of amplifier and filter do you need?
A amp from Ebay maybe...

Bigun 29th July 2012 02:38 AM

As far as I know the FR88EX is still a current model. I just recently bought another pair and am in the process of building a pair of MARTELLO's. I got mine from Madisound.

I've found them good with both tube amps and with solid state amps.

hubertus 29th July 2012 12:10 PM

Quote:

Originally Posted by Bigun (Post 3107800)
As far as I know the FR88EX is still a current model. I just recently bought another pair and am in the process of building a pair of MARTELLO's. I got mine from Madisound.

I've found them good with both tube amps and with solid state amps.

Thanks Bigun for sharing the awesome Martello.

I just built a cardboard model for fun, but I'm seriously thinking of using it with the Fr88ex.
http://i.imgur.com/bbIEZ.jpg

Can you recommend an amp that's a value product like the Fr88ex. Maybe LM1875 ?
And about isolating the inside of a enclosure,what type of material do you recommend?

Bigun 29th July 2012 03:06 PM

It looks a lot of fun to play around with this using cardboard.

As for amplifiers, I think your suggestion of a chip amp is a perfectly good one. I have never built one of these, having decided to build with discrete parts for the learning experience. But I wouldn't have any concerns about the sound quality from a chip amp if used within reasonable power levels - suitable for MARTELLO. If you do build a chip amp I would suggest you build a good solid power supply for it as the power supply is a key part of the amplifier and many people have reported that they tend to sound best when the amplifier has plenty of head-room. You may find more of interest here: http://www.diyaudio.com/forums/chip-...ers-guide.html

One additional thing I would try if I were building a chip amp for my MARTELLO is to experiment with variable damping factor of the output - which you accomplish by putting a low value resistor in series with the speaker output and take the negative feedback from after this resistor. See here: http://sound.westhost.com/project56.htm

planet10 29th July 2012 06:00 PM

Quote:

Originally Posted by awqawq (Post 3106151)
2 x Fr88ex costs 100$ in Sweden.

If you are going to spend that much, you might as well go for a pair of FF85wk,

dave

awqawq 26th August 2012 02:07 PM

Quote:

Originally Posted by Bigun (Post 3108217)
It looks a lot of fun to play around with this using cardboard.

As for amplifiers, I think your suggestion of a chip amp is a perfectly good one. I have never built one of these, having decided to build with discrete parts for the learning experience. But I wouldn't have any concerns about the sound quality from a chip amp if used within reasonable power levels - suitable for MARTELLO. If you do build a chip amp I would suggest you build a good solid power supply for it as the power supply is a key part of the amplifier and many people have reported that they tend to sound best when the amplifier has plenty of head-room. You may find more of interest here: http://www.diyaudio.com/forums/chip-...ers-guide.html

One additional thing I would try if I were building a chip amp for my MARTELLO is to experiment with variable damping factor of the output - which you accomplish by putting a low value resistor in series with the speaker output and take the negative feedback from after this resistor. See here: Variable Amplifier Impedance


Bigun what kind of isolation do you recommend using aside from felt?
You can see my work progress on imurl, just scroll down.
I just used the rope to temporarily test them. They sound good. Gonna do the hole for the air also.

I have to materials available. One is a kind of material people put in side-windows to make sure air can come in but debre and dust stay out. And the second one is a pillow from IKEA made of polyster fibres. Witch one would you recomend putting in the martellos. You can breath though bout of them, maybe there of same material.

Bigun 27th August 2012 12:24 AM

I can see you've done a good job of the cutting and gluing up - well done!

The felt I used isn't ideal actually, it's really a bit on the thin side. I think what you have there looks a bit better, the roll of stuff sitting on top of the pillow looks pretty nice and I'd suggest trying that out. If you aren't sure, you could do an experiment of listening to the speaker without the material and with the material, just clamp the back on tightly instead of gluing it at first. But from the photo's looks like that stuff you have will work well.


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