I thought I would do a little write up on my present setup in case it helps anyone else with a similar situation. My method is convoluted, but it gives me the best step response I ‘ve ever eked out of my system. Also, if I’ve done anything stupid, perhaps someone can let me know !
I have two main speakers, and two subwoofers, for playing stereo music (so a 2.0 setup in Audiolense). I have set the crossover point between the speakers and the subwoofers at 69 Hz. The crossover is asymmetrical. The speakers don’t play much below 50 Hz so there’s a steeper roll off for the speakers (2 octaves). The subwoofers can play much higher than 69 Hz, so there’s a gentler roll off for the subwoofers (3 octaves). Rather than dedicating one sub for each speaker, I have each subwoofers playing both channels (ie in mono). They cover the same frequency range. This allows me to fill room nulls a little bit and decrease distortion.
Taget and XO diagram:
Target overlayed on uncorrected frequency response.
Here are the correction filters. I fiddle with the target to try to avoid having a major spike at one specific frequency (it results in a high gain penalty for the sake of a single frequency, especially if <20Hz or >20,000Hz).
The difficulty is that Audiolense does not allow you to sweep the same channel more than once (here I need each sub to have a sweep for the right signal, and again for the left signal). To get around that, I have a special routing in my digital analogue converter. Signals in channels 2 and 4 both go to the same subwoofer (the one on the right side of the room), and channel 3 and 5 both go to the left subwoofer. So, the signal for the left sweeps goes to channels 2&5 (R+ L Subs) for low frequencies and channel 0 (L main) for 69Hz and above. In the measurement window, one sub is labelled “bass”, the other sub “midrange”, the mains are called “tweeter”. Despite the funny naming system, the “bass” and “midrange” play the same range 10-69Hz, the “tweeter” 69-20,000Hz.
I have not separated the tweeter from the woofer on my speakers for this setup. In the past, I have removed the bridge between tweeter and woofer at the back of the speaker and had Audiolense oversee the crossover. But since I did not remove the internal crossover, there was no advantage that I could hear or see in my measurements. I don’t feel like opening the speakers to bypass the crossover. My amps working as mono blocks have 6dB more gain than when playing two channels each (tweeter and woofer). Also, the tweeter seems to be much more sensitive than the woofer. I think this sensitivity mismatch will cause a big correction in AL, which means a big penalty in overall gain. Both facts would decrease the maximum loudness I can play at. Being able to play scarily loud is imperative : )
For reference, these are the measurement before Audiolense correction (left channel shown, 2 subs, 1 speaker):
For the measurements, I decided to try something new. I did sweeps of five seconds, repeating the sweep 10 times, but without moving the microphone at all. I then selected multi seat correction. I figured this would allow me to average 10 identical measurements, reducing any random errors and noise. Not sure if that’s a smart idea. It did give me better results than what I’ve had before (i.e. better simulated and measured step responses). You can see in the pictures, all measurements are within +/-0.5dB of each other, in the 20-20,000Hz range.
For the corrections, I chose to add a mid-band correction. That way all the low frequencies from 20 to 300 Hz are done with a higher resolution (8 cycle window, 6 cycle sub-window), and then after 300 Hz the resolution decreases gradually to 2 cycle window, 1.008 cycle sub-window. I need to click 'prevent bass boost' even though the target is pretty steep in low frequencies, if I want to avoid a big correction under 10Hz.
These are the simulated frequency and step responses.
There is a bit of pre-ringing but really low. Selective pre-ringing prevention makes things worse.
These are the smoothed measured responses in REW (sorry the freq response rolls off in the high freq as I had a slightly different target with this set of measurements, but all the rest is the same).
I included a sim freq response and step response without multi seat, as you can see the results are not as good.
The system sounds good. The image is well centered. The measurements look pretty good to me.
I hope his helps someone. Let me know if I can do anything differently to improve my results.
I have two main speakers, and two subwoofers, for playing stereo music (so a 2.0 setup in Audiolense). I have set the crossover point between the speakers and the subwoofers at 69 Hz. The crossover is asymmetrical. The speakers don’t play much below 50 Hz so there’s a steeper roll off for the speakers (2 octaves). The subwoofers can play much higher than 69 Hz, so there’s a gentler roll off for the subwoofers (3 octaves). Rather than dedicating one sub for each speaker, I have each subwoofers playing both channels (ie in mono). They cover the same frequency range. This allows me to fill room nulls a little bit and decrease distortion.
Taget and XO diagram:
Target overlayed on uncorrected frequency response.
Here are the correction filters. I fiddle with the target to try to avoid having a major spike at one specific frequency (it results in a high gain penalty for the sake of a single frequency, especially if <20Hz or >20,000Hz).
The difficulty is that Audiolense does not allow you to sweep the same channel more than once (here I need each sub to have a sweep for the right signal, and again for the left signal). To get around that, I have a special routing in my digital analogue converter. Signals in channels 2 and 4 both go to the same subwoofer (the one on the right side of the room), and channel 3 and 5 both go to the left subwoofer. So, the signal for the left sweeps goes to channels 2&5 (R+ L Subs) for low frequencies and channel 0 (L main) for 69Hz and above. In the measurement window, one sub is labelled “bass”, the other sub “midrange”, the mains are called “tweeter”. Despite the funny naming system, the “bass” and “midrange” play the same range 10-69Hz, the “tweeter” 69-20,000Hz.
I have not separated the tweeter from the woofer on my speakers for this setup. In the past, I have removed the bridge between tweeter and woofer at the back of the speaker and had Audiolense oversee the crossover. But since I did not remove the internal crossover, there was no advantage that I could hear or see in my measurements. I don’t feel like opening the speakers to bypass the crossover. My amps working as mono blocks have 6dB more gain than when playing two channels each (tweeter and woofer). Also, the tweeter seems to be much more sensitive than the woofer. I think this sensitivity mismatch will cause a big correction in AL, which means a big penalty in overall gain. Both facts would decrease the maximum loudness I can play at. Being able to play scarily loud is imperative : )
For reference, these are the measurement before Audiolense correction (left channel shown, 2 subs, 1 speaker):
For the measurements, I decided to try something new. I did sweeps of five seconds, repeating the sweep 10 times, but without moving the microphone at all. I then selected multi seat correction. I figured this would allow me to average 10 identical measurements, reducing any random errors and noise. Not sure if that’s a smart idea. It did give me better results than what I’ve had before (i.e. better simulated and measured step responses). You can see in the pictures, all measurements are within +/-0.5dB of each other, in the 20-20,000Hz range.
For the corrections, I chose to add a mid-band correction. That way all the low frequencies from 20 to 300 Hz are done with a higher resolution (8 cycle window, 6 cycle sub-window), and then after 300 Hz the resolution decreases gradually to 2 cycle window, 1.008 cycle sub-window. I need to click 'prevent bass boost' even though the target is pretty steep in low frequencies, if I want to avoid a big correction under 10Hz.
These are the simulated frequency and step responses.
There is a bit of pre-ringing but really low. Selective pre-ringing prevention makes things worse.
These are the smoothed measured responses in REW (sorry the freq response rolls off in the high freq as I had a slightly different target with this set of measurements, but all the rest is the same).
I included a sim freq response and step response without multi seat, as you can see the results are not as good.
The system sounds good. The image is well centered. The measurements look pretty good to me.
I hope his helps someone. Let me know if I can do anything differently to improve my results.
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