Tweaking my x-overs; opinions sought

[sura]

I've been playing around with the crossovers (N1201-8A) in my Model 19's, trying to "mellow" them out a bit. These speakers always seemd a bit "harsh" in my room. The caps have been replaced with Solen. The most noticable change came when I changed the MF L-pad (R-1) wiring. Instead of 1 - 8 ohms, it is now 0 - 35 ohms (the same as the HF L-pad (R-3) (this is simple to do, just move one wire)

The MF L-pad is "upstream" of the HF circuit, and I am concerned of the effects this change will have to the HF. I'm seeking input from those that can look at a circuit change and predict the outcome. What's the effect of increasing the R-1 value?

N1201-8A schematic (http://home.earthlink.net/%7Ejmarkwart/sitebuildercontent/sitebuilderfiles/n1201-8a.pdf)

I know what my ears tell me, but I'm looking for come confirmation.

I also found that moving the speakers out further from the rear wall eliminated some bass boominess that had bothered me.

Many thanks.

[DaveV]

I purchased a pair of Model 19's fairly recently and I listened to them for two weeks with the original xovers intact. I found that the 19's were more enjoyable to listen to than the Flamencos I had been using for about 5 years and I also found myself listening to entire LP's rather than just selected bands like before. Well recorded LP's just sounded so good that I was drawn into them and I found myself listening to the music rather than the equipment/speakers as I have been doing for so long. The one annoying thing I found is the sort of laid back or recessed lower midrange compared to the Flamencos but I chaulked that up as the 1200HZ xover in the 19's where the woofer works more into the midrange than the Flamencos. I was hoping nes xovers might eventually help with that. I changed the 2.7 mh woofer inductor a couple of times using different types and wasn't sure which one I liked better as the difference was subtle in the lower bass, yet there. The big change came when I decided to do a quick xover recap. All I had on hand were misc Solens that I could parallel to make the values needed. I clipped out the original caps on one end and soldered the Solens across the old caps. I proceeded to play some jazz LP's that had previously captivated me on the 19's. There was a balance change yet the sound had opened up and distortion level had dropped. Then I started to play other LP's with vocals only to find that some were so harsh sounding that I could not listen to them. Then I remembered the time I used a Solen in series with an EV T350 tweeter and the sound was so piercing that it wasn't tolerable. In switching to other types/brands of caps I found that there was a huge difference in HF sonics and I finally settled on metallized polyprops of a particular brand that I later also used in my Flamenco xovers with great success. I have now ordered the same brand in the correct values for my 19's so I can replace the Solens but they have not arrived yet but I do think this is my problem because the "harsh" problem started after I recapped. I could not reconnect the origianl caps for a comparsion because I had sent the 802 drivers to Great Plains Audio to be checked out. That being before the "Solen brightness" issue dawned on me. I wanted to let you know what I suspect before you went crazy trying to voice your 19's when maybe you just need different caps. I had the same experience using Solens for coulping caps in my Mac 225 amp. They were just too bright and harsh sounding. I think you should try different caps in your xovers to see if this is your problem. The Daytons from Parts Express are inexpensive and lots of people like them and some people seem to like paper in oil for xovers. I know NOS Mallory paper in oils sounded great in many ways in series with my EV T350's but I opted for the metallized polyprops because the paper in oils were perhaps too smooth and mellow sounding for me.

[Zilch]

http://audioheritage.org/vbulletin/showthread.php?p=128826#post128826

[4313B]

I clipped out the original caps on one end and soldered the Solens across the old caps. I proceeded to play some jazz LP's that had previously captivated me on the 19's. There was a balance change yet the sound had opened up and distortion level had dropped. Then I started to play other LP's with vocals only to find that some were so harsh sounding that I could not listen to them. Then I remembered the time I used a Solen in series with an EV T350 tweeter and the sound was so piercing that it wasn't tolerable. In switching to other types/brands of caps I found that there was a huge difference in HF sonics and I finally settled on metallized polyprops of a particular brand that I later also used in my Flamenco xovers with great success.Yep, I went through the exact same thing with the JBL Model 4430 back in the late 80's. I then tried unbiased Solens in a few other JBL systems with similar results. One capacitor manufacturer actually recommended a competitor's capacitors for use on JBL compression drivers while recommending his own brand for "everything else". Go figure. When Solen was confronted with this phenomenon a couple years ago their reply was "allow them to break in".

The Daytons from Parts Express are inexpensive and lots of people like them
The cheap Dayton (Bennic) caps do sound good enough especially bypassed with AudioCap Thetas. The ClarityCaps mentioned in other posts are pretty decent too. I recently replaced a bunch of capacitors in some Tannoy's with the ClarityCaps and they definitely offered a better experience.

[DaveV]

Zilch: Your link post was very helpful. Thank you. Your Model 19 Xover info is a valuable addition to this forum. Now that I've printed it out it looks like a good excuse to sit down later this afternoon with an adult beverage to study and understand it. LOL Seems that it was posted after I did my initial "Model 19" search and I probably would not have gone back and found it. I think the info is too valuable to be semi-buried in a "Model 19 gone wrong" thread. Think it should be re-titled and reposted so it shows up better when doing a basic search for "Altec Model 19?" Just a thought. Guess I'm an official old fool with a new toy because I never noticed the "optimum" ranges on my xover faceplates. UGH!
Giskard: Thanks for your input on your cap experience. I was wondering if there were others here that had the same experience as me with xover caps and with Solens in particular. I wasn't aware that Solen was approached with the issue. I don't have the patience to listen to shrill music waiting for a "breakin" to occur so I like caps that sound good from the start. In the last 8 years I've become a believer regarding cap sonics. Before that I believed a cap was a cap was a cap.
Sura: Thanks for your post that lead to this wealth of info and I hope you benefit from it too. Before I tampered with the original xovers I was basically impressed how the 19's, even in a small room with me sitting 8 feet away, sounded pretty balanced and smooth and were capable of capturing dynamics even at lower listening levels. Most people would say that monster speakers with a horn can't be used in small rooms but that's not my experience so far! The other interesting thing I noticed is that the bottom doesn't fall out at low listening levels. It's almost like the 19's have a built in "loudness control." I think the original xover is very workable with parts upgrades but the choice of parts may be tricky if your interested in some personal voicing on the way. There are other alternatives like bi-amp and a more straight forward xover network like that shown in Ultra-Fi Times issue #6 but sometimes it's just easier to stick with a known rather than get side tracked with what seems like endless experiments that lead to confusion over what really sounds better. The Iconic Model 19 xover upgrade is yet another option if you have the money.

[4313B]

I don't have the patience to listen to shrill music waiting for a "breakin" to occur so I like caps that sound good from the start. In the last 8 years I've become a believer regarding cap sonics.Well, there are a bunch of them out there to choose from and everyone seems to have their favorites. Mixing and matching dielectrics and brands seems to be popular. I notice that some of the favorites amongst vendors change based on quantity pricing and availability.
Who'd a thunk it! :rotfl:

The Everest II, like all TOTL JBL's, runs biased Solens and there is virtually no shrillness or harshness present. Bizarre. Anyway, I've gone round and round about this with JBL, there is no perfect formula. You pick your caps and then give them a yay or nay. Or go active and forget about it. :p

Bypassed and Biased Capacitors. (http://www.audioheritage.org/vbulletin/showthread.php?t=3555)

[johnaec]

Bypassed and Biased Capacitors. (http://www.audioheritage.org/vbulletin/showthread.php?t=3555)Dammit Giskard! After reading those, I'll probably never be happy listening to my speakers until all the networks have been rebuilt... :banghead: :rolleyes:

John

[X_X]

...Or go active and forget about it. :p


Yes, for sure. Especially when the speakers in question are 2ways! 2ways seem to benefit all the more from going active where it's merits become obvious. You can tighten the crossover point by going with a steeper slope and not introduce any audible distorion by doing so. Plus, you can often boost the point itself to get a flatter response. 2ways beg for active crossovers. ...just my opinion.

[4313B]

Dammit Giskard! After reading those, I'll probably never be happy listening to my speakers until all the networks have been rebuilt... :banghead: :rolleyes:

JohnI don't believe that at all.

[johnaec]

I don't believe that at all.Yeah, I know - 'was just kidding. :) But while I've long heard of the benefits of biasing extolled, those papers really illustrated the significance of doing so...I hadn't really understood the details before - thanks for the links!

John

[4313B]

Ah!

G.T. recently had time to bias the network in his 880 Array center channel and said the improvement was well worth the effort (The Array Series networks weren't biased due to cost constraints.). I don't always go biased. I didn't bias the networks in my Tannoys. I used unbiased ClarityCaps instead. You know, English capacitors for English loudspeakers. :p Whatever! :rotfl:

[Ian Mackenzie]

Breaking in seem to be more an issue with the metalised variety than film / foil capacitors. I don't know why.

I bought some Hovlands (a favourite of Tannoy lovers) a few years ago and they hardly changed after the first hour of playing but with Mundorfs I have been advised around 200 hours break in by the vendor.

An off station FM signal is an old trick for burning in capacitors.

Ian

[Shane Shuster]

Ah!
I didn't bias the networks in my Tannoys. I used unbiased ClarityCaps instead. You know, English capacitors for English loudspeakers. :p Whatever! :rotfl:

I think they are made in Scotland. Better hunt down some Scotish caps.:)

[4313B]

I think they are made in Scotland. Better hunt down some Scotish caps.:)I almost typed U.K. because I knew someone would micromanage my post.

But... then I didn't.

Thanks for stepping up to that task Shane!

[Shane Shuster]

Thanks for stepping up to that task Shane!

No charge, Giskard. Call me if you ever need anything nitpicked to death.