L-Pads. Speakers Awful Without Them, New Ones Ordered


I removed the L-Pads, the tweeters are way too bright, screechy above mids. Disturbing. Played my best source: R2R, Sgt. Peppers. Normally magnificent. Unlistenable!

Using my Chase Remote Control to cut Treble temporarily, until new L-Pads arrive.

I ordered these 16 ohm pads:

https://www.ebay.com/itm/153892668925

mine don’t have the issues he discusses, my insulation is modern, crossovers are tar filled metal cans, not much heat in 6.3 cu ft; these and originals were large ceramic body.

Will put the tweeter ’Brilliance’ ones in first, listen. Then add ’Presence’, listen, decide: leave in, or out. IN more than likely. They (orig and 1 set of replacements) have been IN for 62 years.

My original bronze ones came from original Fisher console, they were a custom version, still labeled ’Brilliance’ and ’Presence’.
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Many of these old Electro-Voice designs had L-Pads (16 ohm used AT37 Attenuators; 8 ohm used AT38). 2 way have one. 3 way designs have two: ’Brilliance’ and ’Presence’.

You can balance the drivers to each other, and to each space, and as you age, ability to hear highs diminishes, you can creep the tweeters up speck by speck. Imbalance due to irregular spacing: adjust each individually

I’m not going to measure and install a fixed resistor, I want future adjustability.

’L-Pads: Terrible Idea’. Bullshite, everyone who ever heard them loves them!

And, let’s not forget, the originals, with L-Pads, first one mono speaker, later two for stereo, are the designs that made these companies successful.






elliottbnewcombjr

intactaudio

I looked up L-Pad, I see what you mean about 2 stages to maintain impedance shown to the crossover (or amp).

https://en.wikipedia.org/wiki/L_pad

The original electro-voice AT37 Attenuator was indeed an L-Pad, maintaining a 16 ohm load to the crossover. (AT38 was the 8 ohm version)

I remember it having the dual 'stacked' design.

https://products.electrovoice.com/binary/AT37%20and%20AT38%20EDS.pdf

I replaced them years ago with 16 ohm L-Pads, (also dual stacked design) the ones I just removed, I still have them. The speakers sound awful without them.

When I wanted to put level controls back in, why not new? I searched and found the ones I ordered, not understanding about constant impedance shown to the crossover.

They do seem to be a single resistance design, thus they would vary the impedance shown to the crossover, thus affecting the crossover frequency. Their screw terminations mean I can avoid solder, try em, keep or return them.






I just found Bob Crites web site

https://critesspeakers.com/electro-voice-crossovers.html

email:   bobcrites@gmail.com

I wrote and asked for prices for new diaphragms for 62 year old horns; new x336 three way crossovers; new AT37 L-Pads
oldhvymec

I agree, before I hook up a vintage piece, I take off the bottoms, tops, sides, anything removable, especially the face plates in my shop, You need face plates off for real access to the pots and rotating contacts. Then hose the pots and controls of tape recorders, tuners, receivers, amps, preamps with contact cleaner/lubricant, blow dry with compressed air, repeat. 

Then, frequently, while in the system, I swish em full spin back and forth, keep the contacts clean, re-check balance after doing this just in case.

I also tend to leave my preamp volume set, zero noise, and use more modern equipment's volume control up/dn from there.

Surprisingly, all my tube stuff is and has been dead quiet, My McIntosh SS C28 preamp, noise started at 11 o'clock, that's another reason I like my Remote Line Controller.

Another reason to have efficient speakers, to keep the volume/work of the components in a lower state.