Beyond the Ariel - Page 781 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 20th August 2012, 07:40 PM   #7801
diyAudio Member
 
Lynn Olson's Avatar
 
Join Date: Jul 2004
Location: Northern Colorado
Quote:
Originally Posted by DaveCan View Post
Sounds like a sexy design and perhaps a worthy alternative for those who have aspirations to collect the bits and pieces to build a M19.. GPA has now just released their own crossover for the M19, making it a one stop shop for all the bits except the horn etc..

I read somewhere that Bill at GPA says there is really no audible difference between the Alnico 416 and the Ferrite version, so maybe that could help shave the cost down a bit for some?

I hate to disagree with Bill, but the Alnico 416B (Classic Series) sounds just amazing - going out on a limb here, but it's the best bass driver I've ever heard. The first thing you notice are the vivid tone colors of the instruments, and the in-the-room naturalness of the singers. I really wouldn't want to give that up to save $100 on the driver. Relative to the other costs of the speaker, including deluxe crossover parts, the AH425, and the compression driver, that's not really a major saving.

(Comment on magnet sound: if you can hear the difference between nickel-core, M6-core, and amorphous-core transformers, you most certainly will hear the difference between driver magnets. It's a very similar kind of sound. Alnico, to me, sounds a lot like nickel-core transformers, with lots of sparkle and immediacy to the sound.)

I've not heard a Model 19, but the hallmarks of this speaker are the delicacy and immediacy of the Alnico-magnet bass, the midrange effortlessness of the large-format compression driver, and the silky-smooth and unhornlike sound of the LeCleach' T=0.707 horn.

This may sound weird, but in terms of the presentation, the new speaker is kind of halfway between a wall-sized electrostat and a Klipschorn. Spatial impression is very deep, with performers in-the-room, but the performing acoustic going back about 30 feet or so. But the dominant impression is the vividness of tone colors, subtle dynamic shadings, and what seems like unlimited headroom (in reality, about 10 dB better than commercial audiophile speakers).

One thing I've learned from this project is that horns are far more sensitive to crossover adjustments than direct-radiator drivers. The low-slope (1st and 2nd-order) crossovers had more IM distortion than I could accept, even with the large-format compression driver. Twiddling with the corner shape was also quite audible as well - the more conventional Butterworth alignments had noticeable energy pile-ups near the crossover frequency, which impaired driver integration and led to a sense of spectral tilting. I gradually went to softer and softer corner-frequency shapes until the impression of energy pile-ups went away - basically, fiddling with the group delay until it fell below a perceptual threshold. Filters that are transitional between Bessel and Linkwitz-Riley 4th-order seem to work fine.

Last edited by Lynn Olson; 20th August 2012 at 07:55 PM.
  Reply With Quote
Old 20th August 2012, 10:24 PM   #7802
ScottG is offline ScottG  United States
diyAudio Member
 
Join Date: Feb 2003
Location: US
Quote:
Originally Posted by Lynn Olson View Post
I hate to disagree with Bill, but the Alnico 416B (Classic Series) sounds just amazing - going out on a limb here, but it's the best bass driver I've ever heard. The first thing you notice are the vivid tone colors of the instruments, and the in-the-room naturalness of the singers. I really wouldn't want to give that up to save $100 on the driver.
That ebay price is quite attractive for a driver of that size with an Alnico magnet.

Do you have a 1 meter response for it, and T/S param.s?
__________________
perspective is everything
  Reply With Quote
Old 20th August 2012, 11:20 PM   #7803
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
Quote:
Originally Posted by Lynn Olson View Post
Filters that are transitional between Bessel and Linkwitz-Riley 4th-order seem to work fine.
Hmmmm... pretty much were I landed, too. Well at least for the acoustic slopes - electrical is whatever it takes to get there.
__________________
Take the Speaker Voltage Test!
  Reply With Quote
Old 20th August 2012, 11:46 PM   #7804
diyAudio Member
 
Join Date: Nov 2003
Location: California
Quote:
Originally Posted by ScottG View Post
That ebay price is quite attractive for a driver of that size with an Alnico magnet.

Do you have a 1 meter response for it, and T/S param.s?
I measured a pair of them in boxes outdoors as being fairly flat up to about 1kHz.
  Reply With Quote
Old 21st August 2012, 03:19 AM   #7805
diyAudio Member
 
charliemb's Avatar
 
Join Date: Mar 2011
Quote:
Originally Posted by Lynn Olson View Post
The new loudspeaker is around 99~100 dB/metre/2.83Vrms, ...
The bass driver is an Altec/GPA 416B (Alnico magnet, 16 ohm version), the HF horn is an Azurahorn AH425, the large-format compression driver is either a Radian 745Neo (Neodymium magnet, 16 ohms) or Altec/GPA 288 (Alnico magnet, 16 ohms), and the passive crossovers ...
...
No inband equalization is required for either the woofer or HF horn system. The system is time-aligned with all drivers in-phase; the lip (outer edge) of the AH425, by lucky coincidence, is about 1/2" forward of the front face of the bass cabinet, with about 2" of vertical spacing between the top of the cabinet and lower edge of the AH425. The bass cabinet is about 4.5 cubic feet and uses a resistive vent.
No mention of the supertweeter here. Is it abandoned or not needed?
  Reply With Quote
Old 21st August 2012, 04:12 AM   #7806
Banned
 
Join Date: Nov 2006
I am not Lynn but I honestly don't think it is needed. I have the Radian 475pb horn, and I don't think you get much bang for your buck by adding a super tweeter

Last edited by Melon Head; 21st August 2012 at 04:14 AM.
  Reply With Quote
Old 21st August 2012, 07:54 AM   #7807
diyAudio Member
 
Lynn Olson's Avatar
 
Join Date: Jul 2004
Location: Northern Colorado
Part of the reason for a supertweeter is improved dispersion. The LeCleac'h T=0.707 horn with a 1.4" throat has audibly narrower dispersion above 5~7 kHz. It's not a laser-beam, but the off-center listener hears a moderately duller and less 3D pinpoint sound than the central listener. With a supertweeter coming in at 7~10 kHz, the sweet spot gets much wider - 3 listeners or more - while adding a touch of sparkle at the top.

The LeCleac'h horn has a completely different spatial presentation than a conical. There's a sort of searchlight on-off quality to the conical - if you're "in the beam", you're quite aware of the sound coming right at you, and when you move out of the beam, it seems to shut off suddenly. This is a subjective preference, but it's not a quality I like personally.

The LeCleac'h sounds more like a direct radiator, with soft edges, and no spotlight tendency at all. It's more like a circular electrostat, a traditional paper-cone tweeter, or a very smooth fullrange driver without a whizzer. The sound fills the room, rather than all coming right at you. Again, a subjective preference, but one I like.

There are several good candidates for supertweeter. Most of the horn supertweeters are inferior to the treble from the large compression driver, a testament to the quality of the aluminum diaphragm and good phase-plug design. I didn't try the exotic Goto and Ales supertweeters.

The super-high-efficiency ribbons like the top-of-the-line RAAL Lazy Ribbon are an excellent match, along with Heil AMT tweeters like the Beyma TPL-150 or Aurum Cantus Aero Striction, which also have high efficiency and high power handling. All of these match very well with the Radian 745Neo or Altec/GPA 288 Alnico, which have a much sweeter and relaxed treble than typical small-format compression drivers.

The trick is to select drivers with complementary dynamic characteristics. The Altec/GPA 416B Alnico calling card is dynamics and tone color. The Altec/GPA is different from modern prosound drivers; the voice coil is underhung, which means the field lines cutting through the coil are straight, instead of the curved lines that go through the outer portion of an overhung coil. The Altec/GPA cone and sticky-surround have very smooth out-of-band rolloff characteristics, almost like the much smaller Vifa 5.5" driver. This is not true for many modern prosound drivers, which need out-of-band notch filters or brickwall filters.

Compared to small-format drivers, the large-format compression driver has a much more relaxed presentation with an impression of unlimited headroom - the tradeoff is the top octave.

The supertweeter has to have enough subjective headroom to keep up with the large-format driver. Not only does this mean a high crossover frequency, but preferably a supertweeter designed for professional monitoring applications.

Last edited by Lynn Olson; 21st August 2012 at 08:17 AM.
  Reply With Quote
Old 21st August 2012, 08:08 AM   #7808
pos is online now pos  Europe
diyAudio Member
 
pos's Avatar
 
Join Date: Feb 2008
Location: Paris
Lynn, have you tried the TAD ET703?
In my experience the BMS 4540nd (or JBL 2407H) is also a good candidate for a supertweeter.

Last edited by pos; 21st August 2012 at 08:19 AM.
  Reply With Quote
Old 21st August 2012, 10:49 PM   #7809
diyAudio Member
 
Join Date: Jun 2003
Location: Wroclaw
Quote:
Originally Posted by Lynn Olson View Post
The super-high-efficiency ribbons like the top-of-the-line RAAL Lazy Ribbon are an excellent match, along with Heil AMT tweeters like the Beyma TPL-150 or Aurum Cantus Aero Striction, which also have high efficiency and high power handling. All of these match very well with the Radian 745Neo or Altec/GPA 288 Alnico
Lynn great to hear the project is at it's final stage and that such obvious solutions from the past with some today's knowledge work wonders.

Have you actually heard the above mentioned as supertweeters (the Aurum Cantus, Beyma...) or you are just judging on the technical data?

Also could you elaborate a little bit about the box and using the resistive port, how you came at it, it's performance etc..

Thanks getting back and continuing with this project
  Reply With Quote
Old 22nd August 2012, 01:53 AM   #7810
diyAudio Member
 
Join Date: Oct 2005
Lynn, did you also experiment with tractrix horns for the mids? I understand that the LeCleach is very good but as you mention -and I read it elsewhere as well- it is quite directional, while (if I am not mistaken) tractrix horns seem to disperse the sound better.
Any comments?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 11:59 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2