James' Quasars

[Max N]

Hello James
I have been meaning to post about your Quasars for ages, but have held off because I don't want to tread on any toes. I also thought that sooner or later someone else would ask the question, but as far as I know, no-one has. I see you have posted a picture to the gallery, and this has finally prodded me into action.
To get to the point, I would love to build a pair of speakers like your Quasars.
My reasons for hesitating so long before posting are:
1. I have no knowledge or experience of speaker design or development, so I would be entirely dependent on your assistance/advice. I would hate to impose on your generosity, so if you have too much on your plate please say so and I'll drop the idea :-)
2. You have put a lot of effort into the development, and for all I know you may have plans to exploit your design commercially.
3. Obviously our host Peter sells speaker kits, and I don't want to tread on his toes either.
4. I belive the original design was a collaboration with Burt Doppenburg, although he now sells a markII version which is quite different (active bass etc), but I can see that there might also be issues there.

If none of the above are issues, then what I had in mind was something along the lines of a group buy, to include any other people who are similarly smitten. I know you have already sent drawings to red-display and Andy thinks he could make the perspex enclosures.
The group buy could include the drive units, crossover components etc.

On another thread, Peter did suggest that someone should start a poll in the wish list section to gauge the interest in a design along the lines of your Quasars - that might be another way to go.

I suspect there will be a lot of interest from others if this gets off the ground, but I think the first step is for you to say whether you are happy with the idea, or whether you would prefer to handle things another way, or whether you have other plans, or whether you are too busy, or whatever :-)
I hope you will think that imitation is the sincerest form of flattery :-)

Also, Peter, if you think this suggestion is inappropriate, just say so and I'll drop the idea.

Over to you James

Max

[petercom]

Go ahead, I'm all ears. The open baffle system is not 'magic' it just gets rid of the box. There's a lot to be said for this but the compromises it introduces are considerable. The falling bass response below 300Hz is the major one but there are ways to ameliorate this as the Quasar design shows. But you still need to bolster the low bass, which is why the designer eventually resorted to active bass.

We'll be exploring this a bit further in Hi-Fi World in future months, together with a set of measurements that indicate the problems and how to start solving them. This will finalise with a WD kit but, as always, I am keen to learn from, and perhaps co-operate with, those who have already worked on this type of design.

[Scottmoose]

A WD dipole? I'll look forward to that! Siegfried Linkwitz' Orion's (http://www.linkwitzlab.com/) are the best speakers I've ever heard, bar none. Not cheap of course (wish I could afford them) but they are frighteningly good. I've devoured all his numerous huge articles and projects; it's the best speaker-resource on the web I know of, along with Martin King's www.quarter-wave.com . Martin's got a new OB MathCad worksheet finished, which is amazingly accurate (and useful -I've been playing with it for a couple of months to good effect).

I seem to remember someone a few years ago on DIYaudio actually cloned the passive Audio Artistry Vivaldi dipoles Linkwitz (allegedly rather unwillingly) designed. Needed a monster amp of course due to the passive correction, but he was a happy camper.

[IslandPink]

Max -
I think James is away , probably on hols at the moment . I'm sure he'll get back to you in some detail once he returns .
I will say the Quasar I as per James's has the disadvantage of drive units totalling around £2000 , so there may not be too many takers for a group buy of anything . I do know however that various cheaper design schemes for OBs are afoot, off this board . I'm certainly interested in something long term and will be interested in any info people can find on transparent materials ( perpsex ) and their working/finishing .

Mark

[Scottmoose]

Two DIY OB projects that might be somewhat cheaper than Bert's Quasar spring to mind straight off:

1) You could try a hybrid of Martin King's OB project, with a cheaper Fostex Fe166E, FE167E, FE206E or FE207E instead of the expensive Lowther DX driver he used, and retain the Dayton woofers , which aren't too expensive in relative terms -you can import them from Parts Express etc I believe. Martin actually suggest this approach recently on a DIY audio thread -will try to dig it out for you. In the meantime, his original project is here: http://www.quarter-wave.com/Project07/Project07.html

2) The now infamous Dark Star, begun by a friend of mine, Dan Mason, on the Red Wine Audio section of Audiocircle. All 98-odd pages of it, at the time of typing. http://www.audiocircle.com/circles/i...?topic=19253.0 There are innumerable variations of this, using the Visaton B200, with various helper woofers or off-panel bass horns electronically crossed over. Again, Martin's OB worksheet (there is a nominal charge now, $25 I believe, but you get all the sheets, plus upgrades, and new sheets as they appear for a year -a bipole one is on the way) is your friend, along with Linkwitz's site for sizing them.

[vitalstates]

Hi Scott

I can't get on with that Linkwitz URL you posted. It seems to be one of those 'go-everywhere with adverts' type of links. Any chance you could be more specific?

Regards

Ed

[Scottmoose]

Blast! Sorry, I mistyped. This is the correct link: http://www.linkwitzlab.com/

I'll edit it in my first post too to prevent confusion. Bow down and workship the God of the dipole! The Phoenix project has a mass of additional designs etc and theory in it, and his articles under the Concepts heading are all extremely valuable. SL clearly is no fan of monopoles, but he's quite fair about it too, and backs up his statements with a mass of theory.

Best
Scott

[James D]

Hello All,

Just back from short break - like 5 minutes ago Straight on the board of course

I'm quite happy to help out with a design or do one. I'm doing a couple at the moment for some friends off board - I'll talk to them and see if we want to move this on board.

The Quasar with its original drivers is expensive, as Mark has said... but my cheapest varient uses drivers that cost about £200... and has limitation in loudness to match (pretty goood frequency extension though)

Needless to say I'd be happy to co-operate with Peter on thiss too

J

[Max N]

Peter, thanks for being cool with this :-)
Scott, thanks for those links, very useful
James, I hope you had a nice holiday. Thanks for the quick reply. Could you give me some idea of the driver options? Rough price points and what the compromises are? Up to and including the Quasar spec. £2000 does sound steep, and maybe I don't need to spend that much, but I'd like an idea what the trade-offs are - any advice much appreciated. As NickG said in the Toccata thread, sometimes spending a bit more is cheaper in the long run if it gets you off the upgrade merry-go-round.
Also, guideline requirements for placement and room size if possible, and do these vary depending on the driver package?
To give you some background on where I'm coming from, I'm currently using IPL S3 tlm's, which I like a lot, but really they need a bit of power to sound convincing. They're very good with PP 300B, but I'd like to be free to use SE as well. The mid/bass drive units have taken a battering from my son, and will need replacing if only for cosmetic reasons, but the current model drivers won't fit my enclosures, so I'm looking at buying new drive units and building a new cabinet just to get back to where I was.
So I figure if I'm going to be investing money, time and effort I might as well build something new.
Other speakers I've owned in the past and liked include Epos ES11 and Dynaudio somethings, both using transistor amps.
The best speakers I've heard with SE amps (although not in my system) are your Quasars and the Coincident Technology Super Eclipse III. The Super Eclipse is about £5000, a bit steep, and I think even to try to clone it would be expensive because of the drive units used.
Cheers
Max

[Scottmoose]

You might find this thread of interest: some useful stuff here. You may find Martin's posts / advice, particularly those on page 2 and 3 of particular value. http://www.diyaudio.com/forums/showt...threadid=83452