Finally, I have ALTEC VOTT A7 !!

GM · February 14th, 2012, 02:57 AM

Originally Posted by voice of the theater

Your question regarding "which is the best option" is not going to have a unanimous answer. It's largely based on personal preference. Some people will tell you that bi-amping (two stereo amps--one for the left channel and one for the right) is always better, and some will tell you that a crossover like the Model 19 crossover (N1201-8A) that Ron is recommending with it's built in h.f. compensation and built in midrange and treble EQ controls, will sound "better" (to them) than many (most?) bi-amped systems. Personally, I am using the N1201-8A crossover in four speaker systems in my house (two pair of Altec Model 19's) and they sound phenomenal! However, I am using that crossover with Altec 802-8G drivers and Altec 416-8B woofers in a completely different cabinet than what you own--I personally have no idea what the N1201-8A will sound like with your specific system/cabinets/drivers. Ron seems to think it would be a good match and I know for a fact that he knows more about this stuff than I do. I would definitely agree with Ron's main point--what he is trying to tell you is that unless you are really knowledgeable regarding electronic crossovers and bi-amping, it will be very challenging for you to get your system to sound as "good" (let alone "better") and to have anything resembling a somewhat flat frequency response with the electronic crossovers/bi-amp setup than with a great/appropriate passive crossover.......

In other words, your system should sound great with two appropriate Altec passive crossovers (one for the left channel and one for the right) and one stereo amp. It will be very difficult for you to equal that "classic Altec VOTT sound" with the electronic crossovers and two stereo amps unless you are very knowledgeable in using that type of set-up IMHO.....

Indeed, as good as vintage Altec [mid] bass drivers sound, I don't like them XO'd up as high as the M19, especially the A7/511 combo. Altec did it to increase power handling, turning the 511 into little more than a large wave-guide [WG], but isn't necessary for a typical HIFI/HT app.

All the OP needs is a N501-8A [or DIY clone] if the OP wants a 'classic' Altec sound and for a truly vintage sound, add impedance compensation and use a tapped auto-former in lieu of the 501's pot plus drive them with a high output impedance amp, preferably with adjustable bass, treble controls. The HF diaphragms would of course have to be swapped out to convert the 808 to an 802 and if SS driven, then empirically find the right value by-pass resistor to allow the highs to be let through unattenuated by the XO same as the 1201 does.

FYI, bi-amping is using one amp for the woofer and one for the 'tweeter' to electrically isolate them, though of course one or both pairs [if stereo] can be monoblocks.

GM

**RonSSS** · February 15th, 2012, 02:17 AM

As much as I like the M19/1201-8A crossovers, I have to agree with GM here.
The 15" woof just isn't happy at 1500 hz. And you can really hear it on female vocals that have a bit lower range. The woof beams and just doesn't sound right.
I think with a 414 woofer, it would be a lot better.
Too bad Altec didn't use the same principal with a crossover freq somewhere between 500 and 1000hz.
Ron

**VolvoHeretic** · February 15th, 2012, 02:56 AM

Interesting direction this thread is heading. I haven’t anything else other than my two Altecs to compare to, but the A7’s with 416-8A, 802’s with 511b’s and 501-8a, and the A8 clones with 418-8hII, 32b with what ever driver they might have came with (still don’t know since too lazy to take out 32 flat head screws and look) and also 501-8a sound unreal and great.

All I can say is that if both of my sets have symbiotic diaphragms (probably), and with a slug of Piezo super tweeters (they do

), they sound fantastic (EQ pegged on the bottom with amp bass tone control also pegged). But then again, I am a bass and treble junkie and like my music progressive and loud, just like the live concerts. I guess I will just keep my A8's crossed over at 500 hz and save a $1000.

GM · February 15th, 2012, 11:38 AM

Hmm, the 32 horn is only 'good' down to ~800 Hz and the N501-8A is a textbook 8 ohm 500 Hz/2nd order Butterworth filter, i.e. isn't 'gapped' to spread the XO over a wide BW like most XOs, so don't understand how you can listen to it loud for the simple reason that the driver's diaphragm should have self destructed the first time it was cranked up even if it has a loading cap. At minimum, it should be protected by the inexpensive 800 Hz N801-8A or DIY one by modding the N501.

Note too that with the N501, the dip in response between the woofer roll-off and the horn's, which will be shifted up to around 1 kHz IIRC if it has a loading cap [most likely], should be very audible.

Look at the size of the 511 Vs the 32 to see the gap in low end loading a ~300 Hz lower XO point represents.

Bottom line, something's missing from this 'equation' as presented, but not knowing the real reason why they still function, I can only assume the worst lest someone be mislead into thinking that using an XO point well below a horn's gain BW is a viable one.

GM