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PFM Special - a simpler and more affordable DIY loudspeaker design

So how does it sound? I could say I'm disappointed and I was, wholly disappointed, the sparkle was gone, the projection all messed up. I've lived like this for a while, not really able to settle to music.
That's most odd. Did you move any other XO component and got wires crossed? The messed up projection suggests a fundamental phase shift, which can only occur with a changed transfer function. You might like to trace the XO against the schematic just to be sure.

James
 
That's most odd. Did you move any other XO component and got wires crossed? The messed up projection suggests a fundamental phase shift, which can only occur with a changed transfer function. You might like to trace the XO against the schematic just to be sure.

James

I really don't know what happened...I suspect that one of the kids did something, like unplugging speaker connections and swapped the phase. You see I could have easily missed a swapped cable as I stripped everything down to move some furniture around (on instruction you understand!) and then added the Voyager clones. So it could have been something like that...

When I built the xovers the number of times I traced the damn things out they were doublely right I can assure you!! :cool:

Anyhow, I have a working system again and a revitalised CD player :)

Even my wife has commented how good it is all sounding at the moment, so the hifi must be really impressive.
 
I'm pleased it worked out in the end, Garf. I'm still trying to get my finger out to build the final XO for the PFM-SII.

James
 
I've just simulated the 9300 data into the PFM-Special XO and it looks like you'll be just fine with it. The transfer characteristics are almost identical. The only thing you might need to tweak is R3051, which is currently 5-ohms. Both the Vifa and SS tweeter have the same sensitivity, so it's really going to be a matter of taste. You might like to try 4-ohms for a slightly hotter top end or 6-ohms for a tamer one. The correct level will depend very much on your room.
I'm pleased to read this, as the quality of the tweeter was my biggest concern.

BTW, I've notice that the prices of many things seem to have risen significantly in the years since we were originally discussing this. :(

Also, I've noticed the Madison Iron Cores seem to be unavailable from their site. Is there a suitable substitute?
 
In addition, it seems the Eagle resistors aren't so plentiful with Madisound.

I also see murmurs above regarding a different cap for the tweeters from Solen. I'll have to look into that as well.

I'm still not nearly sufficient as a woodworker, but I have a retired friend with a full shop (he makes amazing cutting boards, loves lathes, etc.), so I'm going to ask if he's interested in spending some time with me. ;)
 
How about a feed and 3 returns from bass midrange and tweeter? then you could use 4 core bi-wire cable.

Pete
 
BTW, I've notice that the prices of many things seem to have risen significantly in the years since we were originally discussing this. :(

Also, I've noticed the Madison Iron Cores seem to be unavailable from their site. Is there a suitable substitute?
It's been more than a decade since these were conceived. I think they call it inflation.

You should be able to find substitutes for the Madisound iron-cores. Jantzen makes a range of cored inductors and I think Parts Express stocks them. Just check that the mH and DCR values are close.

In addition, it seems the Eagle resistors aren't so plentiful with Madisound.

I also see murmurs above regarding a different cap for the tweeters from Solen. I'll have to look into that as well.

I'm still not nearly sufficient as a woodworker, but I have a retired friend with a full shop (he makes amazing cutting boards, loves lathes, etc.), so I'm going to ask if he's interested in spending some time with me. ;)
The Solen caps are very basic, but entirely fit for purpose. My favourite HP cap that gives the biggest gains per buck is the Jantzen Z-Superior. You could also try the Mundorf offerings. As for resistors, I recommend Mills.

Good luck with the build, Mike. I'll relive this adventure vicariously through you.
 
Good luck with the build, Mike. I'll relive this adventure vicariously through you.

Me too! I still love mine.

Mike I have all the technical drawings of the "smooth curve" version if you need them...download the document in my signature :)

Good luck
 
Thanks, guys. I think it should be fun, even though the prices have gone up. :)

That's a great document, Garf! I was trawling through this thread trying to collect it all, and you've done a fantastic job ahead of time. I'm keen on using your visual design. If my woodworking friend is up for the job, I have a feeling he'll try convince me to use hardwood for the side panels (and perhaps the entire exterior). He's really into wood (as am I).
 
Thank you Mike...you'll never know the number of boring meetings I had to sit through to write it. There is a repeat in the document about xovers, my bad.

The only thing I'd be careful of with hardware flanks is them cracking with age and temp. Both the bass baffles on mine are cracked now; doesn't change their magnificent sound though - can't you tell I still love them lots?

I have been thinkiing recently of moving the xovers to their own box rather than the speaker. Not sure what it would bring me as I have the xovers on rubber shock mounts.

Interestingly since moving house I've not put the spikes back on them and they sound great - in two minds...
 
Mike, you will get problems mixing hardwood and MDF they have very different expansion rates due to humidity changes.


Pete
 
Unless your hardwood is less than 1mm thin (veneer) or is used without backing MDF (e.g. E-IX). Even when I tried using a flexible adhesive, the hardwood cladding split when spanning a foot or more.
 
Thanks for the warning, re hardwood encasing. I guess I'll either use veneer, or paint them, and then shut up and be happy. :)

Or perhaps I should get myself some artificial material, like the new Royd Troubadour. :eek:
 
Yeah, i use a lot of Valchromat especially on baffles for boxes I have made for other folk. Works really well with a coatnof oil.
 
Now I have to figure out whether I can get it in Canada. There is a distributor, but it's about 3500kms away. England is probably closer. :p
 


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