Beyond the Ariel

Jump to Latest
#4,382
Hi Retsel, I plan to build rough models first - note models, as in plural.

There's a spectrum of baffle plans, ranging from Magnetar's flat baffle, to Paul W's short U-baffle with felt stretched across the rear, to Gary Pimm's fairly deep (about 12") U-baffles filled with Bonded Logic's Ultratouch recycled cotton. I haven't heard Magnetar's and Paul W's systems, but I was very impressed with Gary Pimm's system when I heard it in Portland. I can report the recycled cotton filling works extremely well as a wideband absorber, and isn't as nasty to work with as fiberglass.

My instincts tell me that I'll probably end up in the middle, with something akin to Paul W's baffle, with an 18" driver down below, and the Altec/GPA 12" Alnico 414 up above. The preliminary measurements by John Atwood indicate that the 414 will have a generous margin of an octave and a half of good sound above the nominal 850 Hz crossover, which greatly relaxes the crossover design.

SunRa, the Swiss design is interesting - too bad about the dreaded whizzer cone, when they could have used the same GPA 604 Duplex that was such a hit at the Munich hifi show (Alexander of RAAL heard the new 604 at the show and his report was very positive). Of course, it doesn't hurt when Jean Hiraga is doing the crossover and system design - one of the genuinely legendary figures we have in audio.
 
#4,384
Alrexander is a very picky customer when it comes to drivers - as he should be, being in the biz himself. I was surprised at his description of the new 604 - the harsh and forward mids of the old Altec Duplex are gone, and Alexander reported it was the mids that were especially beautiful and natural-sounding. He went further and said it was the only musical-sounding speaker at the entire show (dunno if he heard the new Martin-Logan electrostats). So from all accounts, the people at GPA have hit the ball out of the park (to use an American baseball metaphor).

Alexander reported the sonic character of the 604 treble was complementary and similar in character to his own ribbon tweeter. Anyone that has struggled with getting an extremely transparent (and dynamic) supertweeter to integrate with the rest of the system will appreciate the significance of this remark. Based on his audition of the new Duplex, Alexander strongly encouraged me to go forward with the Alnico GPA 288's and the Alnico GPA midbass driver. (The 604 uses the 15" 416 midbass driver, so that's another candidate for audition.)

It's starting to look like the new GPA Alnico line is making friends everywhere - and I'm glad to see Alnico is making a real comeback.
 
#4,386
Tannoy

Can't say the Westminster Royal HE's had much honk to them when I last heard them ...

Lynn, Allen , I guess the GPA 604's don't use alnico ( from what I can see from the pdf , and the vintage ones ) or is it used in the HF section ?
Even so - you seem keen . Allen, how did the tone strike you - presumeably very favourably ?

Mark
 
#4,387
They sounded fantastic! Walked into the room and just sat down and enjoyed the music, and my woman also sat down and was there even after I had got up to ask what they were, and she didn't want to move on!

At hifi shows, this doesn't happen very often.

As I said, I could have a pair for home and never want for anything else, ever.

I think Lynn would be real happy with them, as I know he liked my much reworked UREIs he heard, these "604s" are similar but on a completely different level, and to me, colouration free.

A pair in open baffles with some big OB woofs would be even better I guess.

Regards, Allen
 
#4,390
Various

The Westminsters easily outclassed a pair of B&W 801's I heard alongside, with good source & amp . Just a much more sophisticated sound, which must have been in part due to alnico .

Thanks for the info Allen . The 6moons link Lynn supplied also has the best pics so far. Interesting to see the new GPA versions have a little multi-cell horn now instead of the rectangular one.
6.8 cu ft for the Hiraga ones, I think you can get a bit lower with 8-9 cu ft , which would be good . I notice Jean seems to be using a little horn-tweeter to augment .

Mark
 
#4,391
The GPA web page is sometimes a bit out of date - they offer drivers that aren't shown or described there. It was on one those "hi, how are things going" phone calls they mentioned the 288 was available with an aluminum diaphragm (not Pascalite alloy) and an Alnico magnet - and that they would do semi-custom versions of the midbass drivers in quantities as small as two. I placed my order on the same phone call.

GPA is a company I want to encourage, since TAD is slowly discontinuing their classic Alnico drivers, Tannoys are not available to DIY builders, and the last thing I want to do is encourage the collectors and price-manipulators on ePay. I am very happy that Jean Hiraga is designing their drivers into his latest products - that endorsement speaks volumes.

Is Mr. Hiraga using a special Alnico version of the 604? He could be. Just because it's not on the GPA website doesn't mean they don't make it - GPA does make special OEM versions of their drivers, and these sometimes fall under non-disclosure agreements.

Coaxial drivers are weird ducks - they can sound awful, they can sound great, and you can't tell just by looking at the pictures and paper specs. I would have expected the top-of-the-line audiophile TAD speaker with the beryllium coaxial mid-and-tweeter to sound really wonderful, based on the company's legendary reputation, the attention to detail lavished on the design, and the special properties of beryllium. But the $60,000/pair TAD was actually quite disappointing, with upper-midrange colorations not acceptable in a $3000/pair loudspeaker.

I've heard 604's sound really honky and harsh (the JBL 4310/L100 was developed specifically to mimic the forward midrange of the traditional 604), and I've heard them sound smooth and superbly dynamic. Same for Tannoys - they can sound all the way from really heavily colored to pretty impressive. But their non-availability for DIY and small-run manufacturers takes them off the table, no matter what they sound like.

That Mr. Hiraga is getting such good results with the GPA 604 tells us that a current-production coaxial drivers can offer performance beyond what we've been accepting so far. I'm going to continue with the 288 & 414, but it's good to know there are alternatives.
 
#4,394
Every few months Alexander calls me, using an Internet connection on his end (my computers don't have a microphone, unless you count the Aco Pacific 1/2" instrumentation microphone that stays in its box most of the time). My "contact network", such as it is, is mostly John Atwood, Bud Purvine, Gary Pimm, Allen Wright, Martin Seddon, Bjorn Kolbrek, Alexander, and various calls to vendors. We talk about what's cooking, local politics, industry rumors, and kick various ideas around.

Direct phone calls from the USA to Serbia would astronomically expensive ... hmm, I wonder what the Echelon snoops think of all the arcane audio stuff we talk about? Probably just as technical and boring as the kind of thing ham-radio operators talk about.
 
#4,396
Since it was a phone call, it was easier to draw Alexander out and ask how it compared to the other speakers at Munich, or to the speakers we both heard at the last RMAF show here in Denver. Considering that Alexander had a rather dim opinion of the large-format high-efficiency studio-monitor speakers that he heard on his last trip to Los Angeles, I was surprised at his enthusiasm for the Hiraga/GPA 604 Duplex - which mirrors Allen Wright's.

588.jpg


Looking at Jean Hiraga's previous designs (great thread, by the way), and adding in the mutual endorsement of Alexander and Allen Wright, well, that says something. I met Jean Hiraga at the 2004 ETF and was impressed with his depth of knowledge of the history of audio, his subtle and beautiful taste in music, and his sense of personal modesty. Jean Hiraga is the real article.
 
You must log in or register to reply here.
Top Bottom