My DIY Altec Lansing A7 - Voice of the Theater

[santhosh]

Hi Friends,
This thread will be about my Altec Lansing A7 "Voice of the Theater" speaker build. This was a speaker produced by Altec Lansing Corporation since 1950s and upto late 80s with minor changes over the years. Chances are everyone would have heard this speaker in a Cinema Hall at some time or other as most theaters around the world including India used these. This is the smallest speaker in Altec's Voice of the Theater range and I have made some tweaks for Hi-Fi application as per the Sound Practices Article http://home.earthlink.net/~jmarkwart/sitebuildercontent/sitebuilderfiles/spaltec.pdf.

I am really thankful to Rajiv and Anilva for their constant support and encouragement and also Abhi (Dr.Bass) for his great company and encouragement while sourcing HF drivers in Singapore. Must also mention Soundsgreat for patiently answering my technical questions regarding crossover and also loaning me his 20uF capacitors.

The build is only 80% complete, still need to build a crossover and also need to get it stained (polishing). Currently, I am using only a blocking capacitor on the HF unit for tweeter protection. The Altec 8 ohm 802-8G HF compression drivers with the Altec 811-b horns and are atleast 6 to 10dB more sensitive than the 16ohm LF drivers (both are over 100dB sensitive), so need to attenuate the highs a bit. Currently I am running the LF driver full range with a more powerful amp compared to the HF driver, so this has sort of attenuated the highs a little.

Plan is to drive these with a tube amp when funds permit

I have posted a detailed writeup of this on my DIY website here:
www.DIYable.net • View topic - Altec Lansing A7 "Voice of the Theater" Build

Here are some pics:

From Listening Position:

My new Audio rack, got 2 identical ones made:

Please let me know your thoughts

 

[arj]

Santosh, These look fabulous ! did you do the woodwork yourselves ?
very very impressive ! Could you post your impressions on the sound ?

 

[spirovious]

Congrats,the speakers looks a part of rack & so no cluttering.Nice idea.

 

[prem]

Congratulations Santhosh. Looks really nice. Was all the woodwork also done by you?

 

[santhosh]

Santosh, These look fabulous ! did you do the woodwork yourselves ?
very very impressive ! Could you post your impressions on the sound ?

Congratulations Santhosh. Looks really nice. Was all the woodwork also done by you?

Thanks Arjun and Prem. No, No!! My woodworking skills are not good enough to attempt a complex build like this one. Since this is my first speaker build, I wanted this build to be perfect as it was my first speaker build. I would love to be able to build like this and am working on my skills and have also requested member sudhishkv to teach me and others interested through a DIY workshop.

Initial Impressions are very good. Currently, I am not able to get a complete picture as the crossover is not nailed down yet. I am very happy with the tonality and timbre. The HF is slightly higher and was only able to get a true picture of bass by disconnecting the HF drivers. I managed to tune the bass a bit by removing some damping. Hopefully, will make a first order crossover this weekend. Will post more impressions then.

 

[santhosh]

Congrats,the speakers looks a part of rack & so no cluttering.Nice idea.

Thanks Spiro, still need to add a bit of hardware before the rack is complete. Will be adding some spikes between the shelves and also for the legs. It is a tripod, not sure if can be made out from the pics.

 

[prem]

Hi Santhosh


I am sure by the time you build your next speaker, you would have learnt all about woodworking.

Also wanted to know what are the approx dimensions of the speaker?

 

[ukjeyaraj]

Very nice work. It will be nice if you share the design details.

 

[soulforged]

Really cool build Santosh :clapping::clapping::clapping:

 

[sbg]

Oh boy!.
You do look like a Fastidious DIY guy.
Congrats for the new DIY SPL !

 

[Rajiv]

Hi,

Santosh the speakers are looking great.:clapping::clapping:

I must make a trip to B'lore soon to listen to them.

Below is a picture of the A7 cabinet with the Altec 805 horns. The 811 will look small next to these.

Your wife is certainly not going to like it when you bring them into the house. Just don't tell her you got them from me. I might not be allowed into your home.

Regards
Rajiv

 

[srinisundar]

Santhosh,

Looking good and hope to visit banglore somewhere around next month for another session.

Looks like you are maintaining blogspot too : Welcome to DIYable.net - Home to the DIY'er & Hobbyist and nice to read the same in detail.

 

[sachu888]

Congratulations Santhosh.Your Vinyl rig looks beautiful.

Regards,
Sachin

 

[hydra]

They look awesome, Santosh!

I see that have taken up the space where the B&Ws were setup. Have you left them crying in a corner?

 

[stevieboy]

Santhosh,

Looks absolutely fantastic! And a lovely place to put them too . Eagerly waiting for sound impressions. What is the wood you've used? Looks very good!

Regards


Torque ain't cheap but it sure knocks yer socks off

 

[santnai]

Santosh looks awesome!!!!! Need to make visit to your place to have a feel of it.

 

[captrajesh]

Please let me know your thoughts

Fabulous build there Santhosh. I truly admire your enthusiasm, patience and perseverance. Hope to hear them during my next visit to Bangalore and hope you would've sorted the x-over issues by then.

BTW, I have a feeling that the speakers are located too close to comfort.

 

[santhosh]

Hi Santhosh


I am sure by the time you build your next speaker, you would have learnt all about woodworking.

Also wanted to know what are the approx dimensions of the speaker?

Prem, the dimensions are 33 inches x 45 inches x 25 inches (width x height x depth). It would been 2 inches smaller all around if I had stuck to the original A design. However mid way in the project I decided to make some cosmetic changes to look like an Altec Magnificent which is the same A7 in an inverted configuration where the horn HF unit was fitted in the bass port. The changes I have made are only cosmetic and the internal volume and everything else is as per the original A7 plan.

Very nice work. It will be nice if you share the design details.

Thanks ukjeyaraj, I have posted most of the details and plans in my DIY website during the build. Link here . If you need any other information, please ask and I'll be happy to post here .

They look awesome, Santosh!

I see that have taken up the space where the B&Ws were setup. Have you left them crying in a corner?

Thanks Hydra, the B&W DM-3000s have been moved to the entertainment room while I have decided to let go of the B&W DM-610s, they are in the sale section awaiting a new owner .

 

[santhosh]

Really cool build Santosh :clapping::clapping::clapping:

Oh boy!.
You do look like a Fastidious DIY guy.
Congrats for the new DIY SPL !

Congratulations Santhosh.Your Vinyl rig looks beautiful.

Regards,
Sachin

Santosh looks awesome!!!!! Need to make visit to your place to have a feel of it.

Thanks Santosh. You are welcome anytime.

Thanks friends for your kind words. You are all welcome for a listen once I have sorted out the crossover and minor pending stuff .

Santhosh,

Looking good and hope to visit banglore somewhere around next month for another session.

Looks like you are maintaining blogspot too : Welcome to DIYable.net - Home to the DIY'er & Hobbyist and nice to read the same in detail.

LOL Srini, you are like a google bot and keep track of the entire World Wide Web .

 

[anilva]

Santhosh,

The speakers look very good. I am sure when crossover issue is taken care off, you would need to look at Pass or Tube to pair them and not what you have...

Cheers.