hi there!
i've been searching all over this forum and the internet but couldn't find info to help me with a problem.
some time ago I built a passive monitor controller using a transformer from sowter for my studio. it's is all balanced and employs a few relay based switching functions including phase, mute, mono and dim. it works and sounds great except for when used with the subwoofer. it has to be noted that the subwoofer and speaker are a bit of a special design (adam s3a and sub 10) where the stereo signal goes to the sub first, gets filtered in a passive crossover and then routed to the left and right speaker. to make this switchable I created an 'insert loop'. when switched in, the stereo signal goes out to the sub, gets filtered, and returns the controller to be routed to the speakers by an output selector switch. I drew a block diagram to help make this clear. (sorry for the poor quality but I had to draw from hand, somehow couldn't get this done without proper software...) below is the part of the circuitry cotaining components in the audio path (i.e. relay switch functions left out), which is simply a dim via h-pad and four permanent resistors for a mono switch before the volume transformer.
when the subwoofer is switched in, a considerable amount of high frequency content is reduced, especially at low volume settings and sometimes unequal across left and right channels. additionally, the sub has to be turned way down to get anywhere near a usable level, way below the standard factory mark.
to make a long story short, I'm guessing the load, when the sub is switched in, is still too much although I chose a volume transformer because I thought it was the simplest way for a non-techie like me to avoid this problem in a simple passive circuit. obviously it's not that easy and I'm now looking to add an active stage to help cure this.
what I don't know is what kind and where. do I need a transformer driver circuit before the volume transformer or do I need an active output stage after the volume transformer?
I've come across the 'negative impedance' designs from jensen that look interesting for my purposes. transparency is still a goal, although some might say that a transformer would be the wrong choice from the start. however the purpose of my box is also to interface effortlessly in any environment.
anyway, my question is how would you wise audio gurus of the internets approach this problem? any help is greatly appreciated!
i've been searching all over this forum and the internet but couldn't find info to help me with a problem.
some time ago I built a passive monitor controller using a transformer from sowter for my studio. it's is all balanced and employs a few relay based switching functions including phase, mute, mono and dim. it works and sounds great except for when used with the subwoofer. it has to be noted that the subwoofer and speaker are a bit of a special design (adam s3a and sub 10) where the stereo signal goes to the sub first, gets filtered in a passive crossover and then routed to the left and right speaker. to make this switchable I created an 'insert loop'. when switched in, the stereo signal goes out to the sub, gets filtered, and returns the controller to be routed to the speakers by an output selector switch. I drew a block diagram to help make this clear. (sorry for the poor quality but I had to draw from hand, somehow couldn't get this done without proper software...) below is the part of the circuitry cotaining components in the audio path (i.e. relay switch functions left out), which is simply a dim via h-pad and four permanent resistors for a mono switch before the volume transformer.
when the subwoofer is switched in, a considerable amount of high frequency content is reduced, especially at low volume settings and sometimes unequal across left and right channels. additionally, the sub has to be turned way down to get anywhere near a usable level, way below the standard factory mark.
to make a long story short, I'm guessing the load, when the sub is switched in, is still too much although I chose a volume transformer because I thought it was the simplest way for a non-techie like me to avoid this problem in a simple passive circuit. obviously it's not that easy and I'm now looking to add an active stage to help cure this.
what I don't know is what kind and where. do I need a transformer driver circuit before the volume transformer or do I need an active output stage after the volume transformer?
I've come across the 'negative impedance' designs from jensen that look interesting for my purposes. transparency is still a goal, although some might say that a transformer would be the wrong choice from the start. however the purpose of my box is also to interface effortlessly in any environment.
anyway, my question is how would you wise audio gurus of the internets approach this problem? any help is greatly appreciated!
