vintage_dog wrote:i love the 403A OB, but, on some passages i wish i get a little more extension on the highs. i'd like to experiment with a few tweeters. any suggestions on tweeters that will match the Altecs?
any tips on placement (of tweeter) on the OBs?
thanks
Here's a list of what I've tried and lived with in my system in the order of preference. Applicable not only on OBs but also in any 2-way horn/BR woofer combo that needs help on top.
Expensive vintage horns:
1. Altec 3000
2. Electro-Voice T35
3. Pioneer PT3K
Expensive alternatives I've heard in other systems.
Modern - Fostex T90, T925 and T900
Vintage - Jensen RP302 and JBL 2405
Budget stuff I tried in my system
modern horn - Fostex FT17H
Vintage cone - Jensen P35VH
Cheaper possibilities are 2"-5" vintage Japanese cone type tweeters with alnico magnets hacked from old consoles, TVs or department store speakers sold with 'compact systems'. Cone type tweeters from old German radios have great following they can be cheap or expensive depending on the seller. Likewise, don't overlook cheap horn or cone tweeters from Dai-Chi or Micro. Who knows maybe they are good.
Joel is experimenting with cheap Chinese OEM ribbon tweeters on his 755C maybe he can offer some insights. Expensive ribbon tweeters might work too but given the price and fragility due to their impedance characteristics [not good for SE amps] I'd go for vintage horn tweeters or Fostex.
I've never used a cap greater than 1 uf [paper is my favorite] and a variable L-pad is mandatory to season it to taste or else one goes crazy changing resistors or finding exact values. Check my speaker building tips page for a crossover calculator link and other info:
http://members.myactv.net/~je245/spktips.htm. There are several pages of information on speakers at my website that can be helpful too so please check the other links I posted in this forum.
On the OB I always place the tweeter on the top shelf which sounds fine because I'm at least 2 meters away. If you sit closer the tweeter might not integrate as well. In this case, once you've chosen your tweeter, you can mount it as close as possible to the fullrange driver just like a conventional two-way system to simulate a point source.
JE