Vifa P17/D25 floorstander + XLS subwoofer finished!

[tktran]

Hello,

Just posting to let you all know that a couple of friends have recently finished building their first DIY speakers.

They're very happy. You can see the speakers here at

http://kram0.com/gallery

[David Gatti]

Nice work. How do they sound?
BTW, that has to be the cleanest garage I've ever seen !

[tktran]

Err...

David that's actually a carport.
We swept up after each job, because the cars have to go back in.

Considering the low cost of the drive units, I think they're a decent speaker. It's a bit difficult to evaluate them critically because they're in a room I'm not familiar with (modern decor, reflective surfaces, not unlike a typical kitchen).

The owners seem very happy with them. I think that's more important considering it was his first DIY speaker project.

[Madmike2]

They look very good :-)

I would be afraid of making ported anything in australia. Only thing i see about australia up here in Canada is that all things that slither crawl fly and swin can kill me. SO for your next DIY build a speaker that has self defense lasers for wasting FST's (flying and stingy thingys)

I hope they sound as good as they look.

[Mark Evans]

Hey guys, Thought I better start posting instead of getting my friend (tktran) to always post on my behalf.

The Vifa P17/D25 floorstanders are working but I still need to sand and finish the veneer. The XLS sub is also finished, but a few days ago some smoke came out of it after i was driving it quite hard. I quickly disconnected and pulled it apart. The driver was fine and the amp was barely warm with no char marks/poped caps. Very bizaar and hassn't happend since.

I am very pleased with the sound from the sub/floorstanders together, but there seems to be a room resonance around 100-200Hz. Any ideas of how this could easily be fixed? I can't move the sub around much unfortuately.

http://kram0.com/gallery

[tktran]

Mark brought his subwoofer over to my place, and it sure sounded great. I didn't notice any boomy notes or resonances, but then the room is also a lot larger and the placement was totally different (well clear of walls)

Unfortunately I don't think there are easy solutions to this. At the end of the day, Audio is Acoustics. The source/amplifier/speaker is the playback part of the chain ie. performers, but the rest of it is the room, ie. venue.

Have you tried moving that subwoofer to the opposite side, on the left of the couch facing the tv?

[Mark Evans]

The speakers have been finished! At last a project that has made it out of the garage finished leaving behind numerous other half completed projects. Might put another couple of coats of Danish oil on though. The Organoil Danish Oil I used smells really nice: piney/citrousy like some cleaning products.

As for Madmike2's comments on creepy crawlies: I had never considered that. Hopefully the handful of resident redback spiders (dangerous) living in our garage haven't migrated to the padded confines of one of my speakers.

As with all projects something always goes wrong. With my excitment of a finished project I accidently mixed up the wires from amp to sub to speakers and hooked up the left channel to the right channel. Short circuit protection kicked in but the right channel blew. Have to live with mono music for a fews days until I fix the amp.

I would like to thank Dennis Murphy for his crossover design and driver placement design.

A completed photo and my speakers & crossover blueprints at:

http://kram0.com/gallery

[paulspencer]

Madmike, and I suppose you think we all have kangaroos as pets?

Room resonance peaks are easily tamed with eq, many use BFD, but I prefer Ultracurve, which I also use for my mains. The overall effect is quite a bit more accurate sounding.

Very nicely finished speakers

[Mark Evans]

I have a digital equilizer I made a while back that I could setup. Would some sort of notch filter be the best way to remove the resonance? The equalizer I have uses a TAS3002 IC from TI. They actually provide software where you can input the actual measured response and desired response (flat) and it programs the IC with the desired filter parameters. However that requires me to make/buy some sort of accurate microphone setup.

What are room resonances normally? Just 1 peak? Or are there many siginificant modes ( muliples of the room length or something) Could I make some small analog variable notch filter? Would that surfice?

[paulspencer]

Mark, there are a number of modes in any room, you need to measure to know. Normally they occur up to about 200 Hz. My room is a medium sized room 4 x 5m with 3m ceiling and I have a peak around 35 Hz and a dip around 80 Hz that stand out the most.

Here is a screenshot of the eq I use to get it flat.

A mic is not that hard! You can either do a diy mic with a diy preamp. Or you can get an inexpensive Behringer ECM mic for about $100. You can build your own for about $30. That is AUD. Preamp is another matter.