I've got a slightly modified DG-SE1 (stereo single-ended EL84 amp, see here) powering a set of dbx Soundfield 3x2s.
The system looks like a 2+1, but really it's configured like two 3-way speakers with both of the woofers contained in the floor box. Speaker cables run from the amp to the box, where each channel has a 12dB/oct f=120Hz passive crossover; the low side goes to a woofer in the box (one per channel), and the high side goes to spring clips for running to the satellites.
I'm unhappy with the low-end response. Granted, I don't expect a ton of extension given the small OTs, but sweeping down, there's a massive drop right at 140Hz - then it stays steady until the OTs crap out around 60Hz. I've replaced the drivers (originals were falling apart) and the caps in the crossovers test fine.
Originally, there was an option for a dedicated amp for the woofers that took speaker level inputs from the main amp. That amp is still available on eBay, but it's $100+, so I'm looking to duplicate that functionality on the cheap. I see a couple options, both using a cheap ($22) TPA3116-based stereo amp.
The first option is to tap the amp's speaker outputs with an attenuating low-pass filter and send that through the chip amp into the woofers. For example, if I hang a 1uF cap off of a 9k:1k divider, I get 20dB attenuation plus a 20dB/oct slope from f=177Hz (I would obviously tweak values from there).
The second is to send the amp to the existing crossover, and tap and attenuate the LF side to feed the woofer amp. But I'm not sure what that would do to the impedance that the amp sees, having 8R on the HF side of the crossover and 1k on the LF side.
Any advice?
The system looks like a 2+1, but really it's configured like two 3-way speakers with both of the woofers contained in the floor box. Speaker cables run from the amp to the box, where each channel has a 12dB/oct f=120Hz passive crossover; the low side goes to a woofer in the box (one per channel), and the high side goes to spring clips for running to the satellites.
I'm unhappy with the low-end response. Granted, I don't expect a ton of extension given the small OTs, but sweeping down, there's a massive drop right at 140Hz - then it stays steady until the OTs crap out around 60Hz. I've replaced the drivers (originals were falling apart) and the caps in the crossovers test fine.
Originally, there was an option for a dedicated amp for the woofers that took speaker level inputs from the main amp. That amp is still available on eBay, but it's $100+, so I'm looking to duplicate that functionality on the cheap. I see a couple options, both using a cheap ($22) TPA3116-based stereo amp.
The first option is to tap the amp's speaker outputs with an attenuating low-pass filter and send that through the chip amp into the woofers. For example, if I hang a 1uF cap off of a 9k:1k divider, I get 20dB attenuation plus a 20dB/oct slope from f=177Hz (I would obviously tweak values from there).
The second is to send the amp to the existing crossover, and tap and attenuate the LF side to feed the woofer amp. But I'm not sure what that would do to the impedance that the amp sees, having 8R on the HF side of the crossover and 1k on the LF side.
Any advice?
You are talking abot the last element in tje audio path. But, what about tjr frequency response of the rest of the chain? (Amp, pre, source, et cetera)
How are you measuring? If it's in a room, that could be room effect. My friend had "no bass" and when he got active Buchardts, the room correction showed a 10 dB hole from 50-130 Hz...rather like what you describe. If the hole is due to acoustic cancellation you could put a zillion watts in there to no effect.
If this is an outdoor kinda-anechoic measurement, then publish the whole curve so we can analyze.