PERSPEX QUASAR ver 2.0 prototype build

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Nick
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#16 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Nick »

The surrounds are translucent and so the frame shows through in the light
Fostek's do that as well.
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Paul Barker
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#17 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Paul Barker »

well i hope the drivers work out Collin, if anything I would be encouraged by the translucense indicating perhaps delicacy. Fairly expensive drivers, hope the experiment works out. The look of the cone doebn’t matter, sound is what Im waiting to hear. Look forward to the opportunity.

Must admit I’m weighting up whether to buy an 8” pair to cut out the suspension and glue it to my AE1’s.
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#18 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Nick »

The bass helpers were from a second hand link Ali pointed me to. And having got those and seeing the Li audio drivers were reduced as end of line stock as they had a newer model out. Expect the worst hope for the best :-)
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#19 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Paul Barker »

Yes, well worth a punt.

Their own 15” base helper looks interesting too.
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#20 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Ray P »

Paul Barker wrote: Sun May 31, 2020 5:28 pm Yes, well worth a punt.

Their own 15” base helper looks interesting too.
I was looking at them back along Paul but, as Nick pointed out, they're less efficient than the 10inch full-range drive units. Here's an implementation of an OB using them that I linked to before;

http://www.modelpromo.nl/The%20Liiondia ... peaker.htm
Sorry, I couldn't resist!
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#21 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Paul Barker »

Interesting
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#22 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Toppsy »

Question for JamesD.
Can you advise should the drivers be mounted on the quasar front baffle from the front so the frames are prominent from the baffle or as I have initially mounted them from the rear so they are firing through the cut-out hole. I had intended to router a 1/2" round-over to the holes to assist better radiation of the sound; not needed if they are mounted from the front.
I cannot remember which way you had the drivers mounted on your original Perspex quasars. Due to the compressive foam ring around the frame this would infer they are designed to be mounted from the rear so this foam ring compresses up against the baffle creating a airtight seal. Perhaps more important and critical for a sealed box design?
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#23 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by JamesD »

I mounted both the AER and the Supravox from the front as I've found that I can hear the edge of the hole more than I can the surround overlap onto the baffle. It maybe that a round over would minimise the diffraction/re-radiation from the edge better than front mounting does. I didn't have a router back then to experiment with this - I did try an 45 degree angled cutout for the circle but that didn't seem to help much.

Hope that helps.

ciao

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#24 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by IslandPink »

I mounted mine to the front of the Perspex baffle, accepting the discontinuity from the edge of the frame - but getting it flush would require a fair bit of work.
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#25 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Toppsy »

Many thanks James and Mark for your replies.
Should have asked this question before I routed the holes in the front baffle, but no matter. The holes required for rear mounting are smaller in diameter than those required for surface front mounting so it's going to be neigh impossible to enlarge these now without me making a couple circular hole templates in 4mm ply/MDF to use with a straight cutting template following router bit. However I have managed to router a 5/8" (15.8mm) round-over to the holes which should help reducing any edge diffractions. At the end of the day these are test bed speakers after all and I suspect that should Nick have a set of acrylic speakers made surface mounting the drivers is perhaps the easiest and way to go. However having said that with the Perspex being spec'd at 20mm thick one should be able to have CNC machined rebates to suit the driver frames. Much neater solution.
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#26 Re: PERSPEX QUASAR ver 2.0 prototype build

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At the end of the day these are test bed speakers
Don't sweat the little things. :-)
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#27 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Toppsy »

Agreed. The round-overs only took me around 5 mins to machine and now both speakers are finished.

Just having a bacon butty with a cup of tea so after that will be mounted all the drivers and hooking the speakers up to my 300b amp. I'll just connect the Lii Audio's up first running them full range (no filter) for a few hours and then repeat the exercise with the Supravox. In which time I'll assemble the XO'ers as we discussed so we can easily swap between the series and parallel filters with both drivers in circuit. We can then arrange for you to come over as my one allowable non family member!
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#28 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by JamesD »

Great progress and I think the round over should work well.

Can't wait to hear both of your thoughts on how these will sound :-)
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#29 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Nick »

Yep, looking forward.
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#30 Re: PERSPEX QUASAR ver 2.0 prototype build

Post by Paul Barker »

Me too looking forward to hearing at some point. Good ideas.
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