ALTEC A7 & 300B SET

[scott fitlin]

Use the Altecs within the ranges their truly good at! Excessive VLF will only strain the high compliance suspensions, and not really deliver truly clean deep bass information!

I would opt to tune the 604,s to 40hz or try the 30,s as suggested, and get a really good subwoofer to deliver the VLF properly!

[beto]

David and Scott,

thanks for your posts. Yes, I think 40 Hz will be Ok. for 90% or more, of my music, but 30Hz will be a dream comes true with a Hi Eff. speaker.
I have take the Fq response for the 604/620 combo on the unnoficial site brochure, so that's why I have say "on the paper".
As a general concept , I prefer a sweet mid range sounding system, with a good and controled bass, down to its limits, but clear, articulated, etc. Prefer less, but a very good quality.
Sugestions on enclosures tunned for 40hz?
Regards,
Beto

[tomp787]

Hello,

The 604 can be used in many different enclosures that can be found on the internet. Remember to include your amplifier output impedance when you calculate the tuning frequency. Most speaker software assumes zero source impedance from the amplifier while your amp may have 2 or more ohms source impedance. You can recalculate Qes using the true amplifier output resistance then have the software help with your box tuning.

Regarding the boxes the Altec 620 is good as is Billfort's corner version. Altec also made a corner box called the 606, I believe. Various vintage designs will also work for the 604 like the Jensen Imperial horn and the Karlson K15.

I suggest you build one of each and tell us which you prefer! I am most interested in the corner Imperial and the Karlson K15. I can send you plans if you can't find them on the www.

Regards,
Tom

[ngccglp]

Hi Beto,

I am using the A7-500 (802-8D, 416-8B, JBL 2405) with the Unison Research S2K (15 watts) in a 3.5 m x 3.5 m room !! Believe me, its more than enough power for the A7.
In room this size, you will not be able to realize the full potential of the speakers in terms of the size of the sound stage it is capable of.

But I'm used to near field listening and enjoy the A7 for its transparency and nice bass extension. The speakers does a very good disappearing act.

[beto]

In room this size, you will not be able to realize the full potential of the speakers in terms of the size of the sound stage it is capable of.

Thanks ngccglp for sharing your experience. It's seem that the right thing for my in this moments is to get a pair of 604's drivers, but, the A7 system also is on my thoughs because is the one I have experienced and also love it. Now I'm seeking for componets in my country so this add a little hazard because the availability.
Maybe in the future I can change my equipment to the short side of the rectangle and the A7 will be match better on 5 meter throw.
Regards,
Beto

[beto]

I suggest you build one of each and tell us which you prefer! I am most interested in the corner Imperial and the Karlson K15. I can send you plans if you can't find them on the www.

Thank you Tom for you offer and comments. Now I'm searching for the drivers in my country, so meanwhile I will study wich cabinet will be the best match for my room size/amp output. Accept any suggestion. I don't think that the corner design was for me at this time, since I have placed them on the large side of the rectangle, so corners are far.
Regards,
Beto