New Heathkit AS101 owner - First post.

[gearfreak]

So if I wanted to do some measurements, what would you recommend. I've never done anything like this before and I don't have a proper mic.

No software recommendations per se, I am not rigged up for anything beyond the WT3 from PE, which I use to track experiments to the ports in mine via impedance plot. There are experienced members, and threads about that here though.

* Freeware WinISD does have a signal generator build in, very useful. Consider though the capabilities of the sound[card/device] used / have some baseline to check the output against.

[RonSSS]

I think it needed some messing with, Ron...at least for my taste. The mids are so out in front, the lower frequencies lagged. I added the wood on the bottom of the horn and then put a few pieces of closed-cell foam on either side of the horn leaving about 14sqin per speaker of port. It seems to have helped the bottom end catch up quite a bit. Bass drums are punchier and bass guitar licks are bouncier. The foam might be narrowing the horn dispersion, but it seems to sound great.

You are the listener, so give it some time with various music and see. As Geek mentioned, it is nice to see where it was stock by measuring as he stated, then see how it measures after the tweak. It's a pretty simple measurement. Would be interesting to know where heath had them tuned.
Might also be interesting to mess with differing amounts of stuffing.

Ron

[cradeldorf]

Sounds like your having a hayday with them, Enjoy.

[alancohen]

Sounds like your having a hayday with them, Enjoy.

I am indeed. Thanks. I feel better that the XOs are rewired. The guy that built these originally must have been heavily invested in lead futures. There was solder everywhere. I think I accomplished a 2% reduction in overall weight.

[VolvoHeretic]

Am I to assume that the battle ship navy surplus gray/green color of your heath kit altec drivers is brand specific? I have been wondering why my later 70's A7's were that color and not metalic green or black and nobody had an answer. Neat. Good luck with zeroing in those beauties.

[voice of the theater]

You are the listener, so give it some time with various music and see........Would be interesting to know where heath had them tuned.
Might also be interesting to mess with differing amounts of stuffing.
Ron

I agree--that's what I suggested (experimentation with different port sizes) as a good way to find out which cabinet tuning sounds best to you as far as better low end response....

Another upgrade you might want to try if you want to experiment is to adjust the tuning of the cabinets. AS 101's, like Valencias, were not tuned for really "deep" bass like many later Altecs were (and many other manufacturer's speakers that came along later were--Altec Model 19's, etc.). Those are Altec 416 woofers in your cabs--and they are capable of much deeper bass than you'll get with the stock tuning of those cabs. There are people here who know a lot more about this than I do, but I can tell you that the empirical/scientific method (trial and error method) is a very good way to achieve a "better"/deeper tuning for your cabs. By reducing the port size (blocking off part of the port from the inside of the cab) you can achieve a deeper tuning. You can evaluate your results by listening or by measuring (with a microphone and computer software) combined with listening. For example, you can start by blocking off a small portion of the port by "tacking" a small piece of wood in place to see if you have noticeably improved the bass response, and then blocking off more to see if they sound even better. At a certain point, you'll have blocked off too much of the port and they won't sound right--then you have to go back to a previous tuning/whichever one you liked best and "permanently" block off that portion of the port (use screws to secure the wood you're using to block off part of the

So this cabinet doesn't even have a proper bass reflex port. The horn is only bolted at the top of the cab with two bolts, the bottom of the horn is just floating. The entire horn opening IS the "bass port". Wow. I have some work to do. It's scary how good these are going to sound.

Yes, that opening around the horn is the port. Even though it may not look like it, it is a very specific size that was calculated as part of the design to achieve a specific cabinet tuning. You'll want to decrease that "port" in small increments to find what tuning sounds best to you -- unless you're confident you hit a "bullseye" on the first attempt of adding wood etc.?

[voice of the theater]

I think it needed some messing with, Ron...at least for my taste. The mids are so out in front, the lower frequencies lagged. I added the wood on the bottom of the horn and then put a few pieces of closed-cell foam on either side of the horn leaving about 14sqin per speaker of port. It seems to have helped the bottom end catch up quite a bit. Bass drums are punchier and bass guitar licks are bouncier. The foam might be narrowing the horn dispersion, but it seems to sound great.

DSCF0677 | Flickr - Photo Sharing!

Nice--sounds like you're making good progress/moving in the right direction!

So, I'm replacing the caps. Got one done and just removed the other.

I noticed one thing that might be an issue with the "speaker of lower volume". That is the one that has the replaced 8-Ohm cap. Well I guess the previous owner figured 16-Ohms was close enough.

Oh, and one more little problem. It seems like the two of the caps were run to ground inadvertently.

Attachment 1597

That's the problem with buying used "kits" (I've bought several used dynakits etc.). Often times you have to go through them and fix "iffy" solder connections. I think whoever assembled your crossover should have his soldering license revoked! BTW, do the two speakers sound (more) identical now that you've fixed the solder problems/replaced the caps? Have you cleaned the pots (with deoxit?) yet? Looking forward to your impressions once the tuning mods and crossover restoration/upgrades are complete. From your recent posts it sounds to me like they're really starting to sound great......

[alancohen]

BTW, do the two speakers sound (more) identical now that you've fixed the solder problems/replaced the caps? Have you cleaned the pots (with deoxit?) yet? Looking forward to your impressions once the tuning mods and crossover restoration/upgrades are complete. From your recent posts it sounds to me like they're really starting to sound great......

Yes I cleaned the pots with DioxIT. They seem to work smoothly, with no dead spots and no noise whatsoever. And I completely rewired the circuits replacing all wiring and cleaning up all soldering joints.

And yes, they now sound identical. I ran through a wide variety of music from my computer and they really sound amazing. I am very familiar with a lot of the music in my library and, as certain passages approached, I was eager to see what they would sound like. 95% of the time I was astounded. I even heard a few things that I did not know were there. I love that. Coltrane sounds like Coltrane, Frank sounds like Frank, but like they are in the room. There is something here that cannot be seen on a 2-dimensional frequency response curve. Music is 3, if not 4-dimensional. It's that added dimension that brings the sound out into the room. I'm just a little miffed that it took all these years for me to find this sound.

FWIW, my system consists of a source (TT or computer CD), a tube-based preamp, a 3W tube amp and some speakers. No EQ, no R/L balance, no treble and bass control. Basically, what you see is what you hear. That's the way I want it for now. I want a system that simply tells me what's there. Sometimes you get a crappy song that was recorded well. Other times you get a great song that was recorded poorly. Once in a while you get the best of both and it's magical. I'll judge the good sound engineers myself.

As far as the tuning, I spent a bunch of time with speaker design calculators when I built my first set of full-range speakers. They are 8" drivers and after much calculating and then trial and error, it was found that a 4" port, 4" long made for the best base reflex design. In the Altec Model 19, the port appears to be 2.5" x 11" or 27.5 sqin. Nearest I can tell the "port" (hole in the front) in the Healthkits is about 37.5 sqin. I reduced it about 15 sqin which seems a bit aggressive, but they sound awesome.

So I think I'll leave them like this for a while. My next project is a phono preamp kit and then a 15W OTL. Once I get the OTL running I'll re-access.

[voice of the theater]

Nice job--sounds like you hit a home run! I loved my AS 101's--especially once I gave them a similar restoration/"tune up". Even though they have the same drivers as Valencias, with the Heathkit cabs and Heathkit crossovers mine definitely sounded superior to my Valencias. Please let us know how they sound with the new phono preamp and OTL. BTW, do you mean re-assess (in your last sentence)?

[alancohen]

Yes, re-assess. That's funny.

So I just got word that my phono preamp will be here Wednesday and the OTL will ship tomorrow. That'll give me a couple of days to get to the preamp done and maybe I'll assemble the OTL over the weekend. I'm psyched!