A7 Dilemma

[eb140]

Hello everybody,

I am fast approaching the end of my Altec A7 build (have a look at my progress at THIS PAGE (http://www.bunneraudio.com/Products/altec-lansing-a7-vott)) and am having trouble deciding on what color to paint them in.

I know they were offered in black and gray commonly as well as a blue-ish / teal color on the infrequent side. While I'm looking to recognize the past and heritage of these speakers I also want to do something unique. To make things complicated they need to look good with a giant black JBL 2360a on top!

As of right now, I'm leaning towards a sea-foam green color as seen here
59692

So my question to you - what color are your A7s and can you post a picture to help me decide?

Thank you in advance!

[NickH]

Wow, that's a unique design. What are the drivers?
Looks pretty killer though.
Nick

[eb140]

The correct and most widely used 15" is the Altec 416 I believe. As far as the lower 18" I have no idea... These aren't my speakers I only like the color! :p Due to my in-college-hardly-any-fun-money budget, I am using a Celestion unit, the TE-BS-15300 8ohm.

Mine are traditional and ported on the lower face.

[eb140]

OK,

I found the paint in a can!

I'm leaning towards 'Greenery' from Utrecht Art supply.
http://www.utrechtart.com/Montana-Gold-Spray-Paint--Matte-Acrylic-Color--Greenery-MP-01425-060-i1001033.utrecht

59693

[stephane RAME]

http://kiirojbl.exblog.jp/i30/
http://kiirojbl.web.fc2.com/audio/audio100.htm

Stéphane

[Lee in Montreal]

Black 2360 on top.
Tangerine/orange A7 underneath ? The A7 would be easy to veneer, dye and satin clear.

http://img.photobucket.com/albums/v668/Lee_Vuong/JBL parts factory/DSCN2495_zps7f020e8a.jpg (http://smg.photobucket.com/user/Lee_Vuong/media/JBL parts factory/DSCN2495_zps7f020e8a.jpg.html)

BTW I checked your page. Nice work. Adding rigiity to the original floppy box is indeed paramount. May I suggest that the bass reflex port be "tuneable". Bascially, you may want to tune it to 30Hz, 50Hz, or even 60Hs depending on your drivers. And the medium is so much forward that tuning low might not be as ideal as expected. Which is why, many are increasing the volume of the cabinet. But you could also help the bottom octave with a quality sub for the 20-60Hz region.

[eb140]

Thanks for replying Lee.

I'd always considered an orange color, and tangerine sounds perfect.

I would probably veneer them but they are going to be in my house on campus and will be in a college environment for at least another three semesters. So as might be able to tell I'm not really wanting to invest a significant amount of time on the exterior! From the start of this project I always planned on a restoration after I graduate and get my own place hahaha.

[Lee in Montreal]

Had the outer panels been plywood instead of MDF, you could have easily sanded the surface and dyed it directly, without using venneer. You wouldn't have seen the difference. Finish off with clear. The process is not longer than painting. :)

[eb140]

Ok, painting is over with.

I couldn't make them orange due to a local shortage of decent orange spray paint. Instead I chose a pure cyan blue.

Pictures to follow once I have them all assembled!

[Lee in Montreal]

A7 + 2360

Seems that somebody has done just that

http://www.ebay.com/itm/JBL-2446J-with-JBL-2365A-large-fiberglass-horn-/261267087823

[eb140]

Aha! So I'm not the only one!

I have to say it is a great combo, although I haven't experienced an original A7 system to benchmark it to.

Right now I'm listening to only one sadly, my HF amplifier decided to not output a left channel for some reason. :(

[Lee in Montreal]

Been a few days. Paint has most likely dried and hardened. Time to post pictures and impressions. :eek:

[sean19]

Hello everybody,

I am fast approaching the end of my Altec A7 build (have a look at my progress at THIS PAGE (http://www.bunneraudio.com/Products/altec-lansing-a7-vott)) and am having trouble deciding on what color to paint them in.

I know they were offered in black and gray commonly as well as a blue-ish / teal color on the infrequent side. While I'm looking to recognize the past and heritage of these speakers I also want to do something unique. To make things complicated they need to look good with a giant black JBL 2360a on top!

As of right now, I'm leaning towards a sea-foam green color as seen here
59692

So my question to you - what color are your A7s and can you post a picture to help me decide?

Thank you in advance!
go to youtube and type in faux woodgrain and check it out i am going to do some cabinets soon will post my pics it's awsome what you can do with a little paint and some clear coat by the way awesome looking design

[eb140]

Been a few days. Paint has most likely dried and hardened. Time to post pictures and impressions. :eek:

Yes, how rude of me to keep you waiting!

59811

Well, what do you think guys?

Impressions are plentiful. I've never done critical listening with a fully loaded horn system before so my brain is quite scattered. I'm going to start keeping a legal pad on the coffee table so I can scribble down listening notes.

While I have made great progress and can see light at the end of the tunnel, I still have a problem. My HF amp (yes, I'm driving them actively :D;)) has decided to not give me a left channel. So at the moment it is not a good time to make remarks about the sound as I only have on e tweeter tweeting.

Although there is a problem with my amp, I have noticed a horrendous resonance. It sounds about like 1kz or so, but I haven't verified with measurements yet. Once I sort the HF amp problem I will be doing an array of tests to see (hear) what problems/attributes they have and where I can optimize. The engineer inside me won't let this project die and just let me listen to music!!!

[hjames]

Wow - that color has some POP!
Hope when you get them fine tuned that they sound as good as they look!


Yes, how rude of me to keep you waiting!

59811

Well, what do you think guys?

Impressions are plentiful. I've never done critical listening with a fully loaded horn system before so my brain is quite scattered. I'm going to start keeping a legal pad on the coffee table so I can scribble down listening notes.

While I have made great progress and can see light at the end of the tunnel, I still have a problem. My HF amp (yes, I'm driving them actively :D;)) has decided to not give me a left channel. So at the moment it is not a good time to make remarks about the sound as I only have on e tweeter tweeting.

Although there is a problem with my amp, I have noticed a horrendous resonance. It sounds about like 1kz or so, but I haven't verified with measurements yet. Once I sort the HF amp problem I will be doing an array of tests to see (hear) what problems/attributes they have and where I can optimize. The engineer inside me won't let this project die and just let me listen to music!!!

[Mr. Widget]

Yep, you are not afraid of color! :D

Good luck getting them dialed in... it might require a bit of effort, but what the hell you've gone this far.


Widget

[NickH]

If your running 416's and a solid state amp you want to fill in the cavity for the home flares on the inside of the cabinet. There's many ways to do this. If you use spray foam be careful. The expanding foam can force the cabinet the separate.

They look pretty good. Those 2360's don't look so big all of the sudden, lol. What are you driving them with? Are those bms drivers on the horn?

I used winisd to work on the reflex tunning. I used a rectangular port that was 1.5 inches thick and it was 2" by 10 or 11" wide. I'll have to measure it.

Sounded pretty good, but it still drops something lik6 db below 100 Hz. I liked them at first. But that drop started to drive me crazy after listening to them for a bit. You could alway run a sub and leave them tuned to 75hz. It will actually have better transient response that way.

Enjoy

Nick

[eb140]

Wow - that color has some POP!
Hope when you get them fine tuned that they sound as good as they look!

Haha yes it does. I really didn't care to adhere to the original color setlist because my pair of A7s are so different than the originals.

[eb140]

Yep, you are not afraid of color! :D

Good luck getting them dialed in... it might require a bit of effort, but what the hell you've gone this far.


Widget

I definitely wanted something exciting!!

Effort is one thing I've got. Hoping to finally put some of my NVH vivro/acoustic experience to work and tune these cabinets.

[eb140]

If your running 416's and a solid state amp you want to fill in the cavity for the home flares on the inside of the cabinet. There's many ways to do this. If you use spray foam be careful. The expanding foam can force the cabinet the separate.

They look pretty good. Those 2360's don't look so big all of the sudden, lol. What are you driving them with? Are those bms drivers on the horn?

I used winisd to work on the reflex tunning. I used a rectangular port that was 1.5 inches thick and it was 2" by 10 or 11" wide. I'll have to measure it.

Sounded pretty good, but it still drops something lik6 db below 100 Hz. I liked them at first. But that drop started to drive me crazy after listening to them for a bit. You could alway run a sub and leave them tuned to 75hz. It will actually have better transient response that way.

Enjoy

Nick

Hi Nick thanks for the tips - I'm sure they will be of use.

I custom designed these cabinets and built them from scratch. They are quite different from the original 828 A7 design so I am probably going to do some extensive measurement to make sure I find the problems.

As far as the drivers go, I am using Celestion units for woofers, the TE-BS-15300 8ohm and the tweeters are Selenium D220Ti that have been adapted to fit the 2360 throat size.

Here is a picture from the assembly of the mock up of the high freq system.
59821


Also, thanks for the port info. I plan on making some other ports to experiment with.

I have to say the bass is quite good - you just need to crank it up to hear. The best part of all is how controlled the bass is even at ridiculous sound pressure levels.

[Lee in Montreal]

The 2360's main asset, on top of the great constant-directivity, is the ability to go down to at least 500Hz (even spread), and even 350Hz with some beaming. I checked your Selenium' specs and it seems they might not be the best match for the horns. It looks pretty gutted below 1KHz. Maybe, when the occasion shows up, trying using a 2" driver (2241 - 2245) and apply CD correction to bump from 3.5 Khz and up. It willbe crisp like a 3-way system.


http://zvuk.resolutiongroup.cz/258-546-thickbox/selenium-d220ti-omf-16ohm.jpg

[Mr. Widget]

Here is a picture from the assembly of the mock up of the high freq system.A stack up of adapters like that will very likely cause HF response issues.


Widget

[eb140]

A stack up of adapters like that will very likely cause HF response issues.

Widget

Can you elaborate? I would love to discuss this further. I'm assuming you are referring to the gaps/seams between or at the flanges?

I designed my billet throat adapter to have a similar taper to the 2360A throat and also not adding to much extra distance.

I'll draw up a diagram and do a cross sectional rendering for further discussion.

[Lee in Montreal]

I think that using adapters is changing the focal point of the source, and therefore the dispersion. A theory that needs to be elaborated further ;-)

Lee

[grumpy]

Any discontinuity, whether gap or expansion rate, will cause some level of issue.
Done properly, there's nothing inherently wrong (including dispersion vs some focal point ?)
but have a look at the 2327 1"-2" adapter length (which, granted, does not include a thread
adapter).

[DogBox]

As soon as I saw the end of the 2360 I began to recognise something I did. But I had a JBL 2427 screw-off snout to
use instead of all "those adaptors". If you remember, the 2427 had the 2" fitment. They also srewed off like the 2426.

The inside of the 2427's snout is exponential to be just the trick!

Kind Regards,
DogBox