[Rustycat]

Rhythmik GR Subwoofer by rusty_98070, on Flickr

I just finished building a pair of the GR subs.  I went to 1.5" mdf sides, used some birdseye veneer and made a cat proof screen with monofilament line to protect the driver.  The subs are sitting on some vintage JBL legs.  This system is strickly 2 channel audio paired with some Lowther Academy back loaded horns and a Visaton tweeter.  The listening area has lots of stuff in it that can't be changed, and the listening area is part of a common open area, so total sq footage of the space is probably around 1000 sq. feet.  Should be interesting to see how it integrates.   

[persisting1]

Great build.  I am loving the vintage JBL legs 

[cody69]

Very nice. Clever idea for the cover -- I like.

[Rustycat]

Thanks for the complements guys.  This sub whole integration thing is new to me, so I have a lot of learning to  wrap my head around.  But, after the first few hours, I am happy but obsessive about  moving the subs and fiddling with the settings.  Of course this will abate in time, but it does kind of get in the way of enjoying the music, gggg.

[Rustycat]

Well, just got a real shock while fiddling with dialing in the Subs.  I pulled out a Command test lp to check the setup and started running tones from 10K to 30hz.  30hz was fine, but I've lost my hearing above 6k.  I called my wife in and asked her to listen to the tones starting from 10K hoping that the crossover to the Visaton super tweeter was faulty.  Nope.  She could hear each tone at 10K, 9K, 8K, 7K and it wasn't until 6K that I heard anything.  I asked her if all the high test tones where the same loudness to her and she replied  that they were.
That was a total shock, as I heard absolutely nothing.
I've been reading up on age related hearing loss since this  this AM.  It seems that I'm a bit ahead of the demographic,  as I'm approaching 62 and this type of loss is more often associated with 70 year olds.  At least I don't suffer tininitus.  But what a shock to hear absolutely nothing above 6000 cycles.
Sigh.

[Danny Richie]

So where are those tweeters positioned in relation to your full range drivers? Any pics of that?

[Rustycat]

Sure, there's a link to some pics with the Visaton super tweeter tweeting on top, gggg.
 http://www.6moons.com/audioreviews/vivaldi/academy_3.html

[Danny Richie]

Sure, there's a link to some pics with the Visaton super tweeter tweeting on top, gggg.
 http://www.6moons.com/audioreviews/vivaldi/academy_3.html

Yes, when you place a tweeter over a full range driver like that then it cause some disruptive interference. You can expect 6db peaks and 15db dips across the top end.

You can get the same air, and spacial cues from the tweeter but without the ill effects of you turn the tweeter around and let it face the rear.

I am not sure though, with your high frequency hearing loss, that you will notice much.

[rollo]

Well, just got a real shock while fiddling with dialing in the Subs.  I pulled out a Command test lp to check the setup and started running tones from 10K to 30hz.  30hz was fine, but I've lost my hearing above 6k.  I called my wife in and asked her to listen to the tones starting from 10K hoping that the crossover to the Visaton super tweeter was faulty.  Nope.  She could hear each tone at 10K, 9K, 8K, 7K and it wasn't until 6K that I heard anything.  I asked her if all the high test tones where the same loudness to her and she replied  that they were.
That was a total shock, as I heard absolutely nothing.
I've been reading up on age related hearing loss since this  this AM.  It seems that I'm a bit ahead of the demographic,  as I'm approaching 62 and this type of loss is more often associated with 70 year olds.  At least I don't suffer tininitus.  But what a shock to hear absolutely nothing above 6000 cycles.
Sigh.

  A blessing in disquise. You can can listen to CDs now and SS too oh my.  Kidding aside hope you feel better.


charles

[Rustycat]

Actually, there is no interference between the fullrange lowther and the visaton tweeter, as I crosssed the lowther over to the visaton at 5000 cycles to rid myself of the dreaded Lowther shout.
I'll listen to CDs for convenience, but alas,  just don't find the experience on the same level as lps.  I'm using an Esoteric DV-50 CD source vs. a  a VPI Superscoutmaster, Shelter 501, Peerless 4722 Step up transformer in front of a Bottlehead Seduction Phono, tied in to a Theshold Fet 10, connected to a Sumo Nine SS amp.

[Danny Richie]

Actually, there is no interference between the fullrange lowther and the visaton tweeter, as I crosssed the lowther over to the visaton at 5000 cycles to rid myself of the dreaded Lowther shout.

Yeah that thing can have a shout to it.

That is still a pretty high crossover point though and there will still be quite a bit of out of phase cancellation in the vertical off axis especially if a low order crossover is used.

[Rustycat]

Danny, interesting comments, I'll just say that Dan Wiggins did the crossover work and used a 4th order crossover.  Here's a smooth FQ response he measured:

Academy Visaton FRgrey by rusty_98070, on Flickr

My biggest gripe with these were I felt they didn't play Symphonic Hall music satisfyingly.  I have to say that with the integration of you F12s, I'm finding the weight that I felt was missing on big music.

[Danny Richie]

Danny, interesting comments, I'll just say that Dan Wiggins did the crossover work and used a 4th order crossover.  Here's a smooth FQ response he measured:

A steep 4th order slope will minimize the adverse effects. Wavelengths at 5kHz are only about 2.75" long. So just a minor change in driver alignment is a pretty big phase rotation.

The on axis response won't tell the story. You have to start moving the mic up vertically a few inches at a time to see what happens.

And seeing as that is a 10db scale, that is a pretty good sized peak at 2kHz.

[Rustycat]

Well, there is a reason Lowthers aren't the only drivers in the World, man.....they do have issues.
For the joy they bring in what they do right, they pack along a whole suitcase of issues that have driven more than a few to dismay and discouragement.
Be that as it may, I'm enjoying my time with your 12s.
Regards

[Danny Richie]

Well, there is a reason Lowthers aren't the only drivers in the World, man.....they do have issues.
For the joy they bring in what they do right, they pack along a whole suitcase of issues that have driven more than a few to dismay and discouragement.
Be that as it may, I'm enjoying my time with your 12s.
Regards

That is true.

And don't let my comments sound like a discouragement. Any time a listen to a design with any issues at all, I have a hard time getting past it. Even if they are really good in some areas, a problem area eats at me like a flashlight in my eyes. So I may often get a little over jealous in feeling the need to fix every speaker out there.

I am glad the subs are working out for you. They look great and the grill is very clever.