I Want To Take A Knife To My Altecs

[voice of the theater]

Seriously. I remember reading here a few years ago that some people cut the bug screens out of their 902 drivers with a knife. Does anybody recommend AGAINST doing so? Does anybody have any advise as to the best way to do this? Snap knife? I have a pair of Model 14's with 902-8a h.f. drivers and I'd like to perform surgery ASAP. The high end of my 14's isn't quite as "clear and open" sounding as the high end of my Model 19's--I thought that maybe this would help. I can't imagine that it's good for sound (especially high end) to have to pass through a screen. FYI, I always keep the grills on them when not in use, and they sit in my living room 24/7 -- never outside so bugs aren't really an issue. They have Altec 34647 diaphragms in them which I believe to be original. I'm not worried about the potential for a small reduction in the resale value of my Model 14's if it makes them sound "better" ( I will probably never sell them anyways). Thoughts?

[LOUDER]

Are you sure that's what's giving you the difference ? Are the screens out of the 19's ? If I remember correctly there are four different versions of the 14 crossover. Could you need a capacitor upgrade ? I've never cut the screens out of any of my drivers, but i'm not trying to listen to the finest detail either. The Markwart article descibes a exacto knife and hemostats. Just be careful and make sure you get every last piece. One little strand in the gap or touching the phram will drive you nuts and cause you more work.

[voice of the theater]

My 19's still have screens in their 802-8g's. No, I'm sure the screens aren't causing the difference but figured removing them would help the sound of the 14's. Surprisingly, they actually sound almost as good as the 19's but I think there has to be a way to get the high end to sound "as good" as the 19's and not "almost as good". Both my model 14 and model 19 crossovers have been re-capped with Solen capacitors and sound noticeably better than they did before I re-capped them. I have the "preferred" version of the Model 14 crossover that people who discuss the variations prefer--and the overall balance of treble to mids to bass is excellent IMO. Can you provide a link for the Markwart article that discusses this?

[Audio_by_Goodwill]

This doesn't sound like a good idea to me. Why? I don't know, but it reminds me of a popular automotive modification from a couple years ago. "Descreening" the MAF (Mass Air Flow) sensor. The idea was that without the screen, which was much thicker than window screen, you would get more air flow to the engine, and make more power. The reality, is the screen was to smooth the airflow so that the sensor could get a better reading, by eliminating/reducing turbulence. So while a slight increase of air would be possible at wide open throttle, the turbulence prevented the accurate measurement of that air, at all throttle positions. I was one of the dummies that did it. Finally, yesterday while replacing my MAF with a used one, I was able to carefully (they're delicate) move the screen from the used unit to my housing.

Bowtie, this engine is the big brother to your 427.... mine's a 454 :-) (Okay Okay, mine's a stock Vortec, so you probably make more power)

[Earl K]

All my 902's ( & 908 ) have that windscreen held in place by the cardboard gasket ( apparently, because I haven't removed any of those c-board gaskets ).

Removal seems simple enough though ( given a sharp hobby/exacto knife ).

Restoration would seem to be just as straight-forward.

FYI, all the response curves that I've seen generated in the last 15 years for the M14 ( & it's horn/driver combo ) lead me to one in-escapable conclusion;
> the HF has a builtin curve that's most appropriate for Rock & some Popular music ( where it's roughness goes unnoticed ).

It's HF is far from flat and can't actually ever be made even flat(ish) except with a "Heroic Network" intervention & redesign.
- RichardC ( who was briefly a moderator over at the short lived GPA forum ) said as much ( though he's now a proponent of active everything when it comes to fixing the M14's draw-backs).

Sorry for the bad news, but you'll never get the the same amount of HF from the stock M14 Horn/Driver/network combo ( as what's available from the M19s radial horn ) .



- The standard ( 30923 ) Altec mid-range suppression circuit will take down the mids ( while obviously enhancing what's there in the HF ) but it'll do nothing about filling in that gigantic "V" shaped hole you that see centered at 9K which is an area that most of us can still hear( and notice its absence ) .

(Below) the grey trace shows what's typically available ( HF wise ) from the original M14 horn/driver combo ( EQed with a Z19 network ).



The top trace shows the 511a/GPA 902-8a combo.

[BillWojo]

I removed the screens on my 902's and it was no big deal. Since I was doing a bunch of mods at the same time I can't say if it made a noticeable difference.
I tend to agree that they can't be helping the sound. The primary purpose is to keep bugs out in outdoor installations.
If I remember correctly, I had the gaskets off so I poked through the screens and ripped them out. I do remember it was easy and no big deal.

BillWojo