My turn...A7 restore...

[analog addict]

Yeah I have the attenuator at 7 out of 10 where 10 turns off the 802....



Still not very satisfactory.....

[Altec Best]

AA I had a similar problem when I was tinkering with my 288's/1005's and a 416 in a 612 cab.Granted it's a 288 but it sounds like the same problem.IMO the stock N501's do not attenuate enough.I had mine on 10 and it still wasn't enough attenuation.The horn just plays much louder than the woofer and doesn't blend well enough.Sounds like what your experiencing even with the 802-8G's.

[GM]

Hmm, I assume you have the horn properly wired and if the XO's exterior condition is any indication, the caps may be shot same as my 1970 units. Could be the pots also if not silky smooth/quiet in rotation and of course different folks hear the same, yet not so much. Some folks plain can't stand the 511's sonic signature without serious tweaking and/or using a much higher XO point to turn into primarily a waveguide.

Do the 802s have loading caps? If so, there should be a big broadband dip in the response through the XO BW that doesn't help matters and without by-pass caps it won't sound worth a toot either.

GM

[analog addict]

Hmm, I assume you have the horn properly wired and if the XO's exterior condition is any indication, the caps may be shot same as my 1970 units. Could be the pots also if not silky smooth/quiet in rotation and of course different folks hear the same, yet not so much. Some folks plain can't stand the 511's sonic signature without serious tweaking and/or using a much higher XO point to turn into primarily a waveguide.

Even an idiot like me can understand "High Freq +/Low Freq +" and "ground/common" I do need to check the caps, but the attenuators were de-oxited and fader lubed. Maybe I should try the 802/1" to 1.4" adapter/MR94b combo?

Do the 802s have loading caps? If so, there should be a big broadband dip in the response through the XO BW that doesn't help matters and without by-pass caps it won't sound worth a toot either. GM

Hmmm. Don't know. Can find out easily enough.

[GM]

Hmm, and yet so many folks still manage to wire up horn systems wrong and not remembering if Altec changed their terminal markings for the later series, I'm not sure if you've got it right either, so all I'll say is that the acoustic positive [a+] of the HF horn should be wired to the XO HF+ when the HF horn is offset like in a M19, etc. and reversed [HF+ to horn a-] when the driver's VC's ~line up since the 501's 2nd order filter is 180 deg out of phase.

From this we see that longer horns that hang off the back need to be wired same as a M19 once the proper offset is found.

GM

[GM]

IMO the stock N501's do not attenuate enough.

Yeah, ideally you need either horn loaded or dual 15" for a large format horn.

If you look at GPA's 802G/511 measured response you'll see that the pot should in theory be at position '5' for best blend. At '7', this implies the woofer could be either 'laying down' due to a weak magnet and/or not sealing well to the horn, so not sure what's going on without being there.

GM

[VolvoHeretic]

Analog Addict, I can't remember what you are using for amplification, but when I picked up my A7-500's 35 years ago, I had cristal clear SS pre and power amps with no tone controls. The A7's sound like crap until I bought a graphic equalizer. It sounded great afterwards, although Rock/fusion needs a lot more base and tweeter than Classical …ZZZZZ... I don't care how much distortion the EQ adds, it makes all of the difference between being able to listen and not. I want to add two EQ’s together in series.

[Panomaniac]

My Experience with the A7 and stock crossovers was that there was just way too much overlap in the mids. It ended up a big cluster-**** in the middle. I have the same Altec crossovers (I think). They did, indeed, cross at 500Hz on an 8 ohm load, but that's not what the box and the drivers need.

A.A. if you can spread the frequencies on your active crossover, that's the place to start. You can cheat with a 3 way crossover by leaving out the mids. I'd keep the woofer at around 500-600Hz, but roll the horn up about an octave and start listening and tweaking. If your crossover has a CD horn setting, you should use it. The 511 is going to be fat near the bottom of its range and thin at the top. The CD horn setting can help overcome that as it's mostly a shelving filter.

Do close up that port. A 2-3" gap all the way across is enough.

[Jimmy-time]

I tried to remove mine as well and was unsuccessful, so i have taped them up during the restoration which has made refinishing very hard. I wish I new how to remove them without damaging them.

[Altec Best]

Do close up that port. A 2-3" gap all the way across is enough.

Pano why do you think Altec had such a big port on the 825/828 cab ? If you can get better response by almost halving the size of the port it doesn't make much sense... Unless the over sized port works better for distance, like projecting the sound out into the audience at a (Movie Theater)..