Comparing Speakers

So many things to consider for speaker preference! Room dimension, room acoustics, music taste, amp size and suitability, hearing ability, whether a speaker is ear fatiguing or not, speaker frequency response, bass, treble, mids.. Probably most speakers will be a compromise in some way (although some would seem to have hit a hole in one with their choice), it is up to the one buying the speaker as to which sounds the best (for them). That takes time with each speaker choice, and depending on desire level and whether compromise can be acceptable, a lot of buying and selling.

I think if I didn't already have some idea as to which vintage speakers to hunt for I would look to new as I would just hate all the bartering, the recapping, the refoaming, the Craigslist no-shows, the eBay scams and whatnot. But due to my location all that is out anyway, so I find ways to improving what I have, making what I have sound the best it can be, to me.
 
That is very cool Todd. I got a little lost in your schematic. I don't get how this wires between preamp/power amp/speakers. 35 yrs in the HVAC trades I'm pretty handy but get easily lost with the electronics.
 
That is very cool Todd. I got a little lost in your schematic. I don't get how this wires between preamp/power amp/speakers. 35 yrs in the HVAC trades I'm pretty handy but get easily lost with the electronics.


The amp's outputs to the speakers enter the unit and are switched between the A and B outputs with a common ground between the A and B. The large switches select/or not the L-pads to be inserted between the amp and speakers with the relay switching between them.

The source outputs to the pre-amp or pre-amp to the amp also enter the unit and are also switched in accordance with the A and B. The stereo (audio taper) pots reduce the signal when the A and B are selected accordingly through a separate relay that throws simultaneously. This option/or not can be turned on using the small toggle switch on right of the faceplate which turns on a relay even though a switch is shown in the schematic.
 
Thanks I get it now. The L-pads are in the line circuit before the power amp while the speakers are simply switched with relay contacts, thus no speaker voltage attenuation. Well thought out and nicely engineered. I love the plexi case to show off your work. My chunky, calloused fingers and getting worse eyesight preclude me from ever attempting to build something like that. All I've tinkered with so far is some crossover circuits.

By the way I haven't opened up that Monoprice switchbox to see what, if any, kind of power robbing, distortion adding circuitry might be in there other than the L-pads. It was pretty highly reviewed, albeit by home theater/wired home installers. They compared it favorably to more expensive units like Russound and Niles.
 
Thanks I get it now. The L-pads are in the line circuit before the power amp while the speakers are simply switched with relay contacts, thus no speaker voltage attenuation. Well thought out and nicely engineered. I love the plexi case to show off your work. My chunky, calloused fingers and getting worse eyesight preclude me from ever attempting to build something like that. All I've tinkered with so far is some crossover circuits.

By the way I haven't opened up that Monoprice switchbox to see what, if any, kind of power robbing, distortion adding circuitry might be in there other than the L-pads. It was pretty highly reviewed, albeit by home theater/wired home installers. They compared it favorably to more expensive units like Russound and Niles.

What if I redid the schematic as a simple, key-fob remote controlled, A/B box with line level matching as you change speakers? I can show/source the parts and they should ~$25, less a case to house it in. The hardest things to solder are the pins on the relays which are fairly close together when you are dealing with shielded cable. No ICs to deal with.
 
Hey thanks Todd. I probably wouldn't build it but I'm sure some others might. You should start a thread in DIY and post your earlier schematic I'm sure there are others here who would love it!
 
Thank you all for the wonderful replies and welcome. I'm definitely buying an A/B box. I can solder but that A/B/X box looks pretty complicated for a novice. Any chance on a full write-up with recommended board and parts? I know that's asking a lot, so definitely not offended if you don't have time to do it!
 
Nobody's talking a quick A/B.

Instantaneous A/B comparisons can reveal a lot about a speaker.

I would A/B my L200/300s against my L112s for hours on end at the same volume level. While the L200/300s were superior in almost all respects, this is how I learned that the L112 was reproducing a high frequency that the L200/300 was not. I could hear a specific cymbol in the L112s but not so much in the L200/300s. But you have to play the right tracks to notice this difference.

That's why I came up with a high frequency by-pass for the 2405s that brings this frequency to the L200/300s.
 
Thank you all for the wonderful replies and welcome. I'm definitely buying an A/B box. I can solder but that A/B/X box looks pretty complicated for a novice. Any chance on a full write-up with recommended board and parts? I know that's asking a lot, so definitely not offended if you don't have time to do it!


There is no "board" and the part list is included on the schematic.

I will do up a schematic for a simple remote controlled A/B box with line level matching and show where the parts can be had.
 
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