What are your Open Baffle drivers?

Altec Open Baffles, etc.

Re: What are your Open Baffle drivers?

Postby marty_e » Mon May 17, 2010 4:04 pm

setup1 wrote:
marty_e wrote:....I can't seem to coax them to open up in their current baffle design. Vocals are veiled and highs roll off...


I don't know the Hawthorne but in my years of playing around with audio one thing I always look for in any equipment specially speakers is the quality of midrange. It has to be there to begin with, driver unmounted.

Here's a tip I learned from the late Walt Bender of Audiomart and Scott Stilwell (exporters of vintage equipment to Japan) when hunting for vintage speakers; bring a pocket FM radio with a pair of alligator clips on one end and a mini-phone connector on the other to plug into the earphone jack. Tune to any station with vocals to evaluate the potential of a nondescript vintage speaker using human voice as reference. First time I heard a WE15 horn with a WE555 driver, it was being driven by 1/4W pocket FM radio. IIRC, the specs for this combo was 100hz-5khz BUT It sounded almost full range and was quite LOUD!

With tweeters and compression drivers - listen to articulation of speech or vocals, if all you hear is sibilance, tizz and sizzle, it is no good.


JE, my speaker reference will always be the LS3/5a's. I've long held a personal bias towards British mini monitors and their attendant flaws. While I acknowledge that i will not get the pinpoint imaging from an OB, what I'm looking for is the transparency and lucidity of the human voice, indeed. Horns and piano sound great as is. It's really the how I percieve the artist to be singing through a sheet of paper that I'm trying to address - either via a tweeter or some XO tweaks. i don't know really which way...
marty_e
Fanatic
Fanatic
 
Posts: 1125
Joined: Thu Jun 19, 2003 2:04 pm

Re: What are your Open Baffle drivers?

Postby setup1 » Mon May 17, 2010 4:37 pm

marty_e wrote:JE, my speaker reference will always be the LS3/5a's. I've long held a personal bias towards British mini monitors and their attendant flaws.....


Likewise I used an LS3/5A from '87-'92, along with original Quad ESLs driven by vintage PP amps - EL34 or EL84. My first triode amp was a PP2A3 and it drove the LS3/5A to decent levels in my small apartment but was always running out of steam (7 watts per side) with big symphonic music. So I searched for Altec 755s which, when mounted in my OB sounded very similar to a Quad ESL....the rest as you can see in my website, was history.

So I think I may have an idea where you are coming from with regards to your expectations from the Hawthorne......

Just checked their website and their drivers are from Radian which has a good reputation for replacement diaphragms for Altec and JBL. In practice most musical instruments fundamental notes end at around 4-5khz....
Image
...so if your problem is midrange related, a super tweeter may not be the answer.....

A wider baffle will definitely help the vocal region in terms of added body but it may also be necessary to simplify the present crossover because a lot of modern crossovers use an EQ network. The LS3/5A is a good example of an EQ network integrated in the XO to compensate for its size but at the expense of efficiency.
User avatar
setup1
Citizen
Citizen
 
Posts: 650
Joined: Thu Aug 14, 2003 1:20 pm
Location: USA

Re: What are your Open Baffle drivers?

Postby arnoldc » Mon May 17, 2010 4:47 pm

I concur Joseph, kaya nabanggit ko baka kailangan nya ng horn. Pero since coaxial yun, baka yun mismo ang may problem?
arnoldc
Legend
Legend
 
Posts: 14118
Joined: Mon Jan 20, 2003 2:22 pm
Location: Makati

Re: What are your Open Baffle drivers?

Postby setup1 » Mon May 17, 2010 5:59 pm

arnoldc wrote:I concur Joseph, kaya nabanggit ko baka kailangan nya ng horn. Pero since coaxial yun, baka yun mismo ang may problem?


I can't nail down the issue until I hear it....dami kasing factors sa audio but if it is a co-axial driver, it could be the width of the baffle and the crossover.......
User avatar
setup1
Citizen
Citizen
 
Posts: 650
Joined: Thu Aug 14, 2003 1:20 pm
Location: USA

Re: What are your Open Baffle drivers?

Postby dieya! » Tue May 18, 2010 7:30 am

marty_e wrote:
dieya! wrote:Sir, when I got the Silver Iris I was told not to expect them to deliver bass. But they did, particularly on acoustic instruments. What they seem to lack though are the highs. They sound best on acoustic recordings then on amplified instruments. :)


May i ask what baffle dimensions you employed on the Silver Iris? Mine are 24"x36" but I'm looking to redesign the baffle if needed. I can't seem to coax them to open up in their current baffle design. Vocals are veiled and highs roll off...


Sir, the dimensions are 24X40. I also installed a 3" motorola horn tweeter to have a higher range.
dieya!
Citizen
Citizen
 
Posts: 185
Joined: Fri Jun 10, 2005 9:50 pm

Re: What are your Open Baffle drivers?

Postby Mamimili » Tue May 18, 2010 8:40 am

setup1 wrote:Hi Paul and Marty,

Just a note to your posts, re: baffle size/width

The OB is one of the earliest forms of preventing cancellation between front and back waves from dynamic speaker systems. To my knowledge one of its early implementation was by Western Electric in cinemas. From the pictures I've seen of old WE installations, they were always as wide as practicable.

I'm not a trained engineer or physicist but I think there is a science to baffle width that a lot of modern audio designers overlook (or try to compensate using EQ - passive or electronic, BSC anyone?) just for the sake of satisfying contemporary aesthetic trends and I include boxes - ported, sealed and etc. IMHO, EQ is just a band aid (much like a synthesized acoustic musical instrument), a poor substitute for solid engineering.

Charles Eames, the designer of mid 20th century iconic furniture even knew better.....

Image
Image
Image

I have a monograph of Pierre Koenig works, another well known mid 20th century architect and saw this speaker in his music room.


That's a pretty box Joseph! Any idea of the dimensions?
It looks larger and more rectangular than Goodmans Sherwood design which i had-planned to build, one of these days.
User avatar
Mamimili
Master
Master
 
Posts: 4308
Joined: Mon Apr 23, 2007 9:09 pm
Location: Subang

Re: What are your Open Baffle drivers?

Postby setup1 » Tue May 18, 2010 10:49 am

Mamimili wrote:
setup1 wrote:Image

That's a pretty box Joseph! Any idea of the dimensions?
It looks larger and more rectangular than Goodmans Sherwood design which i had-planned to build, one of these days.


Unfortunately I don't, it is a pretty rare item and in the years I hung out in swap meets I never saw one. This was a picture sent to me by another enthusiast. These Stephens systems were probably snapped up by Eames and mid century modern collectors long before audio hobbyists rediscovered their sonic potential. However I've seen Stephens drivers unmounted, the horn is mid-way in width to an Altec 811 and 511 + the 15" woofer, just to give you an idea of the box dimensions based on the picture. I reckon this speaker system targeted the Altec Valencia market with a bit more budget to burn for a designer's touch.

For a tidbit of history, Robert Stephens was part of the team that designed the Shearer Horn.
User avatar
setup1
Citizen
Citizen
 
Posts: 650
Joined: Thu Aug 14, 2003 1:20 pm
Location: USA

Re: What are your Open Baffle drivers?

Postby Mamimili » Tue May 18, 2010 12:47 pm

So much for my memory!
Goodmans Sherwood
Image
Image
Image

22" width / 24" height / 18.75" deep
The Goodmans would look better if a different wood was used for the baffle (like Eames) instead of plain black.
User avatar
Mamimili
Master
Master
 
Posts: 4308
Joined: Mon Apr 23, 2007 9:09 pm
Location: Subang

Re: What are your Open Baffle drivers?

Postby setup1 » Tue May 18, 2010 1:09 pm

Is that the same pair, refinished? Looks good to me.
User avatar
setup1
Citizen
Citizen
 
Posts: 650
Joined: Thu Aug 14, 2003 1:20 pm
Location: USA

Re: What are your Open Baffle drivers?

Postby Mamimili » Tue May 18, 2010 1:18 pm

Gulp to the Shearer horn!

Has anyone ever used an entire wall as an open baffle?
My room is an extension of a little over 10'x10' and an original corridor which adds 3' over the full 10' width. A major problem is a 3' wall protruding into the area between new extension and old corridor which plays havoc with the soundstage.
I use the mono OB in the 10'x10' area and all is good, but i am fed up having to keep moving it into the bathroom when i use stereo (it puts the stereo soundstage about 10" up in the air).

I cannot move the wall as it is a supporting wall, so i have often thought about putting a frame and plaster board wall up to fully seperate room from corridor and then put my mono use driver and tweeter into the new wall. This would mean a 10' x10' OB but also a 10' cube as a music room.

Another thought, i use an Ikea display unit as a record rack, basically it is eight 13"x13" boxes, open backed, so i could easily fit a 12" driver at the same height as the OB i use now. This would give me a 58" wide 31" high OB.

It just occurred to me that i could also stand the mono OB on top of the record rack, its wide and solid enough and should look ok.
I could also add wings to the existing OB or just use new plywood to end up with a 58"x36" OB. More width = more range right? Happy me if its this simple to do!
User avatar
Mamimili
Master
Master
 
Posts: 4308
Joined: Mon Apr 23, 2007 9:09 pm
Location: Subang

Re: What are your Open Baffle drivers?

Postby Mamimili » Tue May 18, 2010 1:34 pm

setup1 wrote:Is that the same pair, refinished? Looks good to me.


I think i got all three photographs from eBay many moons ago so assume all are of the same units.
I have seen another photograph of them used in a Victorian style living room and they blended very well with the rest of the furniture.

Eventually i will make my own cheap and cheerful boxes first, then if halfway decent i will get a carpenter to make proper boxes with a contrasting wood for the baffle.
All based on the assumption that Goodmans put some effort, calculation and testing into the design!
User avatar
Mamimili
Master
Master
 
Posts: 4308
Joined: Mon Apr 23, 2007 9:09 pm
Location: Subang

Re: What are your Open Baffle drivers?

Postby setup1 » Tue May 18, 2010 6:51 pm

Mamimili wrote:Another thought, i use an Ikea display unit as a record rack, basically it is eight 13"x13" boxes, open backed, so i could easily fit a 12" driver at the same height as the OB i use now. This would give me a 58" wide 31" high OB.

It just occurred to me that i could also stand the mono OB on top of the record rack, its wide and solid enough and should look ok.
I could also add wings to the existing OB or just use new plywood to end up with a 58"x36" OB. More width = more range right? Happy me if its this simple to do!


My G. A. Briggs derived OB dimensions started out as an experiment that I kept through the years because it served my purpose.

Last Nov. Hi-Fi show, the dimensions of the OB built by Rofiel for our mono demo was empirically conceived (guided by the chart below). Basically it had to fit his van when disassembled and his listening room after the show was over.
Image

Image
Keep in mind that this is all theory and presumably free field - room boundaries are not taken into account.

Mamimili wrote:Eventually i will make my own cheap and cheerful boxes first, then if halfway decent i will get a carpenter to make proper boxes with a contrasting wood for the baffle. All based on the assumption that Goodmans put some effort, calculation and testing into the design!


Most vintage drivers where designed for vented boxes. The internal volume to vent ratio determines the bass cut off point. I'm sure there are existing plans in the internet for Goodmans drivers.

Enjoy!
User avatar
setup1
Citizen
Citizen
 
Posts: 650
Joined: Thu Aug 14, 2003 1:20 pm
Location: USA

Re: What are your Open Baffle drivers?

Postby setup1 » Wed May 19, 2010 10:09 am

"Mamimili" wrote: More width = more range right?


Sorry I missed this which I think should be clarified....if you refer to the chart above, the human vocal range (bass, baritone, tenor, alto and soprano) is within the 90hz-1200hz region. The reason why a wider baffle gives more body to the vocal range is due to the overtone series (a by product of a fundamental note) which is what gives any particular instrument or voice its unique nature.

My 36"W x 32"H panel is nominally tuned to around 90hz in free field but is aided by floor coupling in a normal room. I believe GA Briggs did a thorough research on the subject using his knowledge of sound physics and actual listening tests.

If you decide to experiment with the Ikea record rack as an OB, make sure there are no gaps wherein the back wave can escape.
User avatar
setup1
Citizen
Citizen
 
Posts: 650
Joined: Thu Aug 14, 2003 1:20 pm
Location: USA

Re: What are your Open Baffle drivers?

Postby bz » Thu Jul 22, 2010 11:05 am

Mamimili wrote:So much for my memory!
Goodmans Sherwood
Image
Image
Image

22" width / 24" height / 18.75" deep
The Goodmans would look better if a different wood was used for the baffle (like Eames) instead of plain black.


Are you in the Philippines? I would like to find out how the Axiom sounded in a box. I have a pair in OB but contemplating on putting it in a box to see the difference.
bz
Citizen
Citizen
 
Posts: 52
Joined: Fri Sep 12, 2003 2:08 am

Re: What are your Open Baffle drivers?

Postby Mamimili » Thu Jul 22, 2010 11:17 am

bz wrote:Are you in the Philippines? I would like to find out how the Axiom sounded in a box. I have a pair in OB but contemplating on putting it in a box to see the difference.



I have not made the box yet!
When finished they will be in Malaysia.
User avatar
Mamimili
Master
Master
 
Posts: 4308
Joined: Mon Apr 23, 2007 9:09 pm
Location: Subang

Re: What are your Open Baffle drivers?

Postby bz » Mon Sep 06, 2010 9:30 am

Mamimili wrote:
bz wrote:Are you in the Philippines? I would like to find out how the Axiom sounded in a box. I have a pair in OB but contemplating on putting it in a box to see the difference.



I have not made the box yet!
When finished they will be in Malaysia.



Image
bz
Citizen
Citizen
 
Posts: 52
Joined: Fri Sep 12, 2003 2:08 am

Previous

Return to OPEN BAFFLES

Who is online

Users browsing this forum: No registered users and 1 guest

cron