Something stirs in the Undergrowth

[g3dahl]

He brought the 25W ss Tabor, which is described at the bottom of this page.

Here's what the speakers look like now:



Gary Dahl

[Romy The Cat]

Here's what the speakers look like now:

g3dahl, what are the crossover points and what kind filters of those channels? Are they passive line level fitters with multi-amping or they are speaker level filters? Another question: sine you have side-ports and if I presume the speakers are mirrored then how would you describe the difference if you reversed right and left channels?

[g3dahl]

Raal Lazy: 8 kHz passive 2nd order high pass (more revisions to come)
745NeoBe: 800 Hz passive 3rd order high pass
416-B: 800 Hz passive 3rd order low pass (LF is limited to 65 Hz by sealed enclosure)
TD15H: 65 Hz active (plate amp)

These figures are approximate. They are not cookbook crossovers, but have been tuned for use with the actual drivers.

The bass boxes have passive radiators on both sides, so reversing them wouldn't have any effect. They are tuned to 23 Hz and are -3dB at 45 Hz. The plate amps will later be replaced by my QSC DSP-30 and Parasound HCA-1500a. The TD15H's have plenty of linear excursion so equalizing for deeper bass would be easy enough, but the most important thing is natural sound with acoustical instruments, not LF special effects.

Gary Dahl

[Romy The Cat]

Raal Lazy: 8 kHz passive 2nd order high pass (more revisions to come)
745NeoBe: 800 Hz passive 3rd order high pass
416-B: 800 Hz passive 3rd order low pass (LF is limited to 65 Hz by sealed enclosure)
TD15H: 65 Hz active (plate amp)

These figures are approximate. They are not cookbook crossovers, but have been tuned for use with the actual drivers.

The bass boxes have passive radiators on both sides, so reversing them wouldn't have any effect. They are tuned to 23 Hz and are -3dB at 45 Hz. The plate amps will later be replaced by my QSC DSP-30 and Parasound HCA-1500a. The TD15H's have plenty of linear excursion so equalizing for deeper bass would be easy enough, but the most important thing is natural sound with acoustical instruments, not LF special effects.

OK, thanks. Gary you got a good, compact, non-elaborate and not-expensive implantation and I like the direction. A few things you need to consider.
Your ribbon tweeter shall be sitting atop of your MF, on the very same axes and to be curve-aligned. If you feel that your tweeter will take the vertical center image too high then you can drop down you MF channels as in your configuration the LA-horn does not have own typical real-estate problem. Your tweeter apparently does not work properly. It is visible from the comment you made that you feel a need to that you need to adjust your tweeter with different recordings. That is very wrong - your tweeter must have a fixed setting that you will never touch, the most important you have to get this feeling in you - if you do not then work on your tweeter. The Ribbons are very tricky. They have not a lot of tonal character and they hugely compress sound d with each Hz you let them to go down. In my view to use ribbons at 8kHz second order is too low. There is too much tonal information in there and there is too much dynamic transient that ribbon would not do. In your configuration I would like to see a MF driver that would be able to run MF out of tonal range (10kHz -12 kHz), then you can add a Ribbon. I do not know the 745NeoBe driver but I wonder why you chose to use a driver that roll off at 8kHz. You have a horn that looks like 350Hz-400Hz horn and it is not deep. It will support of let say 12kHz driver and ti give to it a very nice gentle attention atop without any beaming. Riming to let say 10 kHz -12 kHz your MF would not be shifted to much with introduction of a tweeter atop on the MF. Also, if I were you then I would for sure time-align your uppperbass with your MF

[g3dahl]

Thanks Romy, many helpful thoughts there. Will definitely keep them in mind when taking the next steps.

Gary Dahl

[Lynn Olson]

Hi Gary! Glad the listening session over the weekend went well ... good luck to all the Pacific Northwest participants.

I agree with Gary Pimm's suggestion to lower the MF horn if possible. If your LF/MF time-alignment is similar to the first prototypes I heard in Dallas, the edge of the horn will be about 1/2" forward of the front face of the bass cabinet. If you choose, the lower edge of the horn could even overhang the frame of the 416-Alnico, although I wouldn't have it overhang the surround or cone of the driver.

Moving the RAAL Lazy 8 crossover a little bit higher isn't a bad idea either. 10~12 kHz is out of the tonal range, as mentioned by Romy, and the natural HF rolloff from the Radian 745 NeoBe is so slow that's it OK to have a little bit of frequency spacing between the drivers. The distance between 8 and 11.3 kHz is only a half-octave, after all. Try a 1st-order HPF at 12~13 kHz, set the level maybe 2 dB below the 745 NeoBe, and see what you think.

You've mentioned in private conversation that the Radian 745 NeoBe doesn't need a supertweeter on most classical recordings, no matter what the measurements say. This is a good sign, and a suggestion that any potential supertweeter should be very subtle in its action. The few horn supertweeters I tried were not exactly subtle, and noticeably coarsened the sound from the 745 NeoAl Radians when they were switched on. Didn't try the crazy-expensive Goto supertweeters.

Since you're a trained classical musician who performs on a regular basis, I'd trust your perceptions first, last, and always. And ... thanks for taking the "Beyond the Ariel" collaboration as far as you have.

[Romy The Cat]

[phivates]

That would apply to any "contribution" from Romy the Jackal. The Slug. The Pathetic Manboy. Go away loser. Pollute another planet.

[Lynn Olson]

A timely post from my favorite San Francisco columnist:

http://blog.sfgate.com/morford/2014/02/ ... net-troll/

http://www.slate.com/articles/health_an ... pathy.html

To return to the topic: Gary, how much did you attenuate (via discrete L-pad or autoformer) the MF/HF system? The figure I remember from a previous phone conversation was 15 dB. If the GPA/Alnico 416 Alnico is around 97~98 dB/metre/2.83Vrms, that would put the 745 NeoBe around 112~113 dB/metre/2.83Vrms, which is pretty close to Radian's numbers.

Also, a quick question for the UK readers: The REL subwoofers use Volt drivers, don't they? Are they special to REL, or does Wilmslow Audio sell similar models, like the Volt driver referenced below?

http://www.voltloudspeakers.co.uk/Louds ... 500_1.html

[steve s]

Also, a quick question for the UK readers: The REL subwoofers use Volt drivers, don't they? Are they special to REL, or does Wilmslow Audio sell similar models, like the Volt driver referenced below?

http://www.voltloudspeakers.co.uk/Louds ... 500_1.html

Blue Aran stock volt drivers, knowing them they will be able to get that model, and at a reasonable price, they are open to a little bargaining too.

If not why not contact volt direct, a few years ago i was intending to buy Precision devices drivers, i went straight to the factory and had a good listen to all their bass speakers, and they gave the best price too. The factory enginner was very usefull, he smiled when i told him i was to use 5 watt valve amp to drive their 21" drivers... I don't think he believed me when i said it would sound much better than their demo system, i ended up buying 4x 18's, although i look back now and wished i'd spent the money on the better quality vintage drivers.

[pre65]

[Lynn Olson]

Thanks, Steve. Much appreciated! I like the sound of the REL subwoofers, but don't like the very steep price here in the USA. Curious to see if the Volt drivers are the reason that REL sounds the way it does.

Historical note to improve the S/N ratio of the discussion: Gary Dahl is a good personal friend and former neighbor back when I lived in Washington State. He's built Ariels, built the Amity amplifiers (that what's lurking on the left side of the photo), and has collaborated on the Beyond the Ariel project along with Bjorn Kolbrek, Martin Seddon, and myself over the last several years. Gary Pimm of Portland, Oregon, has had a lot of useful input as well. Last but not least, JMLC updated the LeCleac'h spreadsheets to optimize the entrance angle for the AH425 built by Martin in Australia.

Gary Dahl is a classical musician with tastes similar to mine, which has made collaboration over 1500 miles of distance a lot easier. I also appreciate his personal experience with the Altec A7 828 version ... he's paid his dues with Altec, so when we talk about 416 and 515 sound, we're on a common wavelength.

IslandPink has "been there, done that" with the Ariels, so I'm really curious what he's up to now. The Ariels are 20 years old, so I'm not surprised he's moved on ... dipoles this time around, from the sound of the discussion a few pages back. Any more impressions of the Tone Tubby's?

[IslandPink]

Tone Tubby is so far proving to be promising, but difficult to run-in .
It still sounds closed-in and lacking in mid tone compared to the Jensen P12N that was on the test baffle before - but I've read several reports on the guitar forums that the TT hemp cones & surrounds need a lot ( eg. 50hrs ) of heavy-duty running-in at 20-30W to get them sounding right . I was using a signal generator via a small solid-state amp to run the (one) driver I'm trialing at 35-40Hz for several hours at a time , but that's been curtailed too early as the signal generator just died a slow death a few days ago
Right now it's in the front room with the casework open and I'm trying to see any clues to what went wrong !

In the meantime I'm likely to go ahead and buy two sheets of 1000mm x 600mm x 20mm perspex for the baffles - just need to check the bank account today .

[pre65]

Mark, I remembered a supplier who used to be active on World Designs forum.

They seemed to have an active interest in the use of perspex and acrylic sheet in hi-fi projects.

I don't know if this info is still valid but worth a try ?

"I found this supplier of perspex and acrylic products on ebay and are based in Driffield Yorkshire, they made a perspex cover for my Lenco as a special order and delivered within 24 hours of order and payment.

They were very cheap too only £34.55 including delivery anyone needing a cover or anything else made from plastic products should give them a try they gave the best service and friendly too.

Email red_display@btinternet.com

Tel 07836 310 793 ask for Andy"

Here is a link to the topic on World Designs.

http://www.world-designs.co.uk/forum/sh ... ht=perspex

[IslandPink]

Thanks Phil - I'll contact him before i order via the EBay seller I found a few weeks ago, to see if his prices are any better.
Current estimate is about £300 + postage for two sheets of 1M x 0.6m x 20mm .
ps. got some axial electrolytics today to replace all of the ones in the Sig Gen circuit boards , hopefully I can get to all of them and it might do the trick - they are 30-40 year old Philips ones so they must be dried-out.