Escher Posted November 29, 2011 Share Posted November 29, 2011 Yes I searched, and yes I understand passive v.s active... So, please refrain from berating me because passive bi-amping has little value .... please read on for my reasons... I'm going to try the small Class T amp route for my system, at least for a little while to evaluate it. As such, and since the amps are so cheap and small, I picked up two and plan to use them in a bi-amped configuration. These are 20W Lepai amps. I plan to bridge the input and then run the tweeter and squawker on one channel and the woofer on the other... simply because of available power. I'm hoping to better balance out the power useage by going the passive bi-amp route... from my research, these amps are best when run under 3-4watts... So, can someone with more Electronics knowledge than me show me exactly where I need to tap into the crossover to isolate the woofer yet still maintain the crossover point for it? I have heard of people running the woofer at full range, but that it will muddy the sound output... so I want to still utilize the passive crossover for this reason. Had anyone got a setup like this that they can snap me a photo of? Thanks!!! Quote Link to comment Share on other sites More sharing options...
Escher Posted November 29, 2011 Author Share Posted November 29, 2011 O.k... Heres my attempt at figuring it out based on the AA schematic - can someone let me know if this is correct? I attached a .pdf of the modified schematic... AA-Mod-1.pdf Quote Link to comment Share on other sites More sharing options...
Southern Posted November 29, 2011 Share Posted November 29, 2011 Your modified schematic looks correct. I bi-amped my Forte's and from my experience you will not have a good balance between your woofers and the mid/highs since you are using the same wattage amps. The woofers should have a more power then the mid/highs. I am running 270 watts of solid state power to my woofers and 35 watts of tube power to my mid/highs without any balance controls between the two amps with great results. Quote Link to comment Share on other sites More sharing options...
DavidF Posted December 1, 2011 Share Posted December 1, 2011 Your modified schematic looks correct. I bi-amped my Forte's and from my experience you will not have a good balance between your woofers and the mid/highs since you are using the same wattage amps. The woofers should have a more power then the mid/highs. I am running 270 watts of solid state power to my woofers and 35 watts of tube power to my mid/highs without any balance controls between the two amps with great results. What are seeking when you mean balance? I would think such completely different amps would have output impedance, gain and possibly polarity differences that would easily throw off the balance between the separated outputs. If you are passively biamping and want to keep the system frequency response matched to the single amp configuration it makes sense to me to use the same model amp. I have a second amp-out with variable gain on my preamp that I use to tweak the levels when using different makes/models of in passive biamp (horizontal) configuration or when I want to lower the output a bit for the mids and highs compared to the woofer. Quote Link to comment Share on other sites More sharing options...
Southern Posted December 1, 2011 Share Posted December 1, 2011 What are seeking when you mean balance? The balance between the woofer and mid/highs. The woofer consumes more power then the mid/highs therefore requires more power to balance the sound. As you stated you can accomplish this with a separate variable gain on the pre-amp or in my case I don't have a seperate variable gain so I run more power to the woofers. Quote Link to comment Share on other sites More sharing options...
Islander Posted December 11, 2011 Share Posted December 11, 2011 What are seeking when you mean balance? The balance between the woofer and mid/highs. The woofer consumes more power then the mid/highs therefore requires more power to balance the sound. That's not always true. It depends on the crossover point. At 480-500Hz, the woofers and tweeters draw the same amount of power (on average, depending on the type of music). That number's familiar to many here, since it's the crossover point for Jubilees and JubScalas. This may make it a bit more clear: at 480-500Hz, the woofers are reproducing the bottom 5 octaves (20-480Hz), while the tweeters are reproducing the top 5 octaves (480-20KHz). Accordingly, they need equal amounts of power. If the crossover point was lower than that, the tweeters would actually need more power than the tweeters. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted December 11, 2011 Share Posted December 11, 2011 O.k... Heres my attempt at figuring it out based on the AA schematic - can someone let me know if this is correct? I attached a .pdf of the modified schematic... with out understanding your before amp signal splitting solution...whaqt you modified on the schematic is perfect for bi-wiring......assuming that you have a signal splitting solution before your amps (passive inline or active inline) , using the passives in between the amps and the speakers is a good idea....how are you going to split the signal coming into your amps? Quote Link to comment Share on other sites More sharing options...
Escher Posted December 12, 2011 Author Share Posted December 12, 2011 I had planned to just run an amp to each input... but more research on active crossovers has me thinking that the balance between drivers would not be correct... Quote Link to comment Share on other sites More sharing options...
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