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Multi-Way Conventional loudspeakers with crossovers

The LM-1 DIY Speaker is Available
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Old 17th May 2016, 12:10 AM   #1
eriksquires is offline eriksquires  United States
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Default The LM-1 DIY Speaker is Available

Dear DIY'ers,

Just to let you know I have completed the design on the 2-way LM-1 speakers. The cost to build is around $500/pair with cabinets. It uses the famous Vifa XT25 ring radiator along with a 5.25" Peerless woofer in a ported enclosure. The complete project information and cabinet drawings can be found from my blog page here.

Click the image to open in full size.

The FR is missing the port, which will be true until after I move, but the far-field data indicates usable output to 50Hz.
Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
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Old 17th May 2016, 07:39 AM   #2
wolf_teeth is offline wolf_teeth  United States
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I agree that the TG30 will not do what you're asking of the BG60.

Was the design intended for sideways positioning then?
Wolf
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Old 17th May 2016, 07:42 AM   #3
eriksquires is offline eriksquires  United States
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Quote:
Originally Posted by wolf_teeth View Post
I agree that the TG30 will not do what you're asking of the BG60.

Was the design intended for sideways positioning then?
Wolf
Hi Wolf,

Call it creative photography. I have gotten jiggy with DSP, so I decided to make the best 2-way speakers I could using quasi-anechoic measurements and then if I ended up using them in a bookshelf use a miniDSP module to shoe-horn them into position. That's worked quite well with the aberrations encountered by the LM-1C.

Best,


Erik
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Old 5th June 2016, 08:09 PM   #4
eriksquires is offline eriksquires  United States
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Hi Everyone!

Instead of packing, I have been tweaking the LM-1 to the B&K reference curve. I personally like that curve a lot, but the LM-1 is eminently customizable. If you find it too dull, change it.

Still, here's the comparison of the LM-1 to the B&K curve:

Click the image to open in full size.
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Old 7th June 2016, 03:36 AM   #5
system7 is offline system7  United Kingdom
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All looks very nice, Erik.

I was simming this today. The ferrofluid XT25 60 is quite a different animal from the Non FF XT25 30. Goes lower crossover.

B&O used to do this sort of thing with (easier, IMO, if you can put up with the low impedance) 4 ohm drivers:

The crossover was something like this:

Click the image to open in full size.
Classic monitor designs?

They used a (big) tweeter that could do about 2kHz too.

I liked the tiny Beovox 2702 back in the student day.
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File Type: jpg Beovox 2702.JPG (39.2 KB, 141 views)
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Old 7th June 2016, 05:43 PM   #6
eriksquires is offline eriksquires  United States
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Thanks, Steve!

This is s opposed to be an educational project. I hope it encourages more music lovers to build their own speakers, as well as encourage listeners to listen to more and different kinds of music, so if you see any glaring mistakes, or places I could add more information please let me know.

After I move I'll be adding all the measurement and simulation files online so it can act as a learning lab.

Best,

Erik
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Old 7th June 2016, 10:59 PM   #7
eriksquires is offline eriksquires  United States
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Yes, the XT25BG60 is an awesome performer when it comes to low frequency extension.

It's documentation is sketchy though. PE claims it's shielded, but that's not in the spec sheet, neither is any information about ferrofluid. I have a feeling there have been so many versions of the XT25 that no one can keep them straight anymore.

What's your source for the ferrofluid in the BG version?

Best,


Erik
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Old 7th June 2016, 11:36 PM   #8
Eldam is offline Eldam  France
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Thanks Erik.
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Old 8th June 2016, 02:51 AM   #9
system7 is offline system7  United Kingdom
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The ferrofluid issue is just something I saw in an XT25 60 pdf. It was mentioned, whereas it wasn't with the single magnet 30. We had similar problems with SB acoustics, which AFAIK, don't use ferrofluid either.

Maybe I'm wrong on that.

Seems like the 60 has a more rigid surround along with a stronger magnet. But for sure has a much better and smaller impedance bump at Fs (12 ohms versus 20 ohms for the 30). Which makes it friendly to simple filters without all the tricks.

I don't see much of a problem with small woofers anyway. They are so inefficient we have more room to manoeuvre. Efficient tweeters with inefficient woofers are easy, IMO.
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Old 8th June 2016, 02:53 AM   #10
eriksquires is offline eriksquires  United States
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+1 about the efficiencies. Far better to have an efficient tweeter than woofer.

Best,

Erik
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