The gap between phase is important when comparing the two since it affects the sounds to other parts of the room. It can possibly be more relevant than the slopes.
I've had great fun and made huge improvements going active on a two way. I used a miniDSP 2x4HD and REW to fine tune things. Since a room can have a huge impact on sound I did mostly a series of listening position measurements.
Regards,
Dan
P.S. I ended up focusing quite a bit on a 'house curve'.
I've found a plot what appears to be the proper impedance curve for the compression driver/horn combo for the HF.
Thanks dantwomey,
I have the TS parameters for the woofer and have recently learned (from AllenB) that I can use REW to measure the impedance curve. Have watched a few videos and this seems straightforward, given that I can do this at line level at the speaker terminals for the woofer. (since I'm bi-amped already)
#34633 TS Parameters
Fs=22.4 Hz
Qes=.1569
Qms=6.8436
Qts=.1534
Zmax=261.65 ohms
Le=2.1394 mH
VAS=380 L (13.42 ft^3)
BL=15.8724 N/A
Sens=96.2 dB@1W/1M
Eff=2.63 %
Assuming I'll need the impedance curve to be able to simulate in XSIM? On a mac, so downloading now and working through how to run in an emulator.
Also, found a few threads on some other Altec Model 14 crossovers I'd like to try out in DSP. Most seem to focus on the HF rolloff and dip.
https://www.hostboard.com/forums/f700/174905-crossover help needed another pair altecs/index2.html
I have the TS parameters for the woofer and have recently learned (from AllenB) that I can use REW to measure the impedance curve. Have watched a few videos and this seems straightforward, given that I can do this at line level at the speaker terminals for the woofer. (since I'm bi-amped already)
#34633 TS Parameters
Fs=22.4 Hz
Qes=.1569
Qms=6.8436
Qts=.1534
Zmax=261.65 ohms
Le=2.1394 mH
VAS=380 L (13.42 ft^3)
BL=15.8724 N/A
Sens=96.2 dB@1W/1M
Eff=2.63 %
Assuming I'll need the impedance curve to be able to simulate in XSIM? On a mac, so downloading now and working through how to run in an emulator.
Also, found a few threads on some other Altec Model 14 crossovers I'd like to try out in DSP. Most seem to focus on the HF rolloff and dip.
https://www.hostboard.com/forums/f700/174905-crossover help needed another pair altecs/index2.html
Hi Allen,
I'm able to run Auto EQ in my DSP to more or less flatten the response at the xover. The various parametric EQs applied are shown and adjustable.
Is this what you mean to focus in on the xover listening? I can also manually EQ for the room with it's RTA
You're tinkering with two things I enjoy. DSP and REW. After going active I consider going back to passive a step backwards.
For the time being I've found too many cool things you can do with REW and DSP filters.
Regards,
Dan
P.S. Slightly off topic. I built four channels of the M2x to power my system and really couldn't be happier.
For the time being I've found too many cool things you can do with REW and DSP filters.
Regards,
Dan
P.S. Slightly off topic. I built four channels of the M2x to power my system and really couldn't be happier.
Here's an RTA shot of the 6db cross with low shelf, white noise - no Auto EQ
Measurement mic is 3' from speaker, pointed in between the woofer at tweeter.
& PInk Noise
Measurement mic is 3' from speaker, pointed in between the woofer at tweeter.
& PInk Noise
Here's a re-measure of the Auto EQ with the mic in the same position as above:
6db cross - HF gain reduced -15db
I'll run a 12db LR cross next
6db cross - HF gain reduced -15db
I'll run a 12db LR cross next
Thanks, it does make things easy!
Because the DSP is on wifi, I can set up the mic and don't even have to be in the same room, lol.
Regarding the M2x, I've been eyeing up the Nelson pass stuff, but it's been out of my personal limits for audio expenditure, but that looks interesting!
My Harman Kardon CD401 uses those same Toshiba transistors (2sk170GR 2sj74) in it's output stage and I like the sound very much!
Here's the xover config I'm trying with 12db LR on both ends - normal polarity. Upped the gain on the HF to -12 instead of -15 looking at the above sweep to bring the top end up a bit.
& the result - ignore the title as i didn't take the time to save it under a different profile. Looks like I can bring up the highs a bit more & happy to reverse polarity on one of the driders and try again. I see the 'room' response in grey still has that ~3k dip ~-6db before the auto eq, which appears to have fixed it with the #6 peak. (clicking on it shows 2.9Khz + 5.7db with a Q of 6.26.
I believe I can also se the target curve to a harman model instead of flat to see hot that sounds.
Open to suggesions on what to tweak or polarity changes that might help reduce the gain required at "point 6"
& the result - ignore the title as i didn't take the time to save it under a different profile. Looks like I can bring up the highs a bit more & happy to reverse polarity on one of the driders and try again. I see the 'room' response in grey still has that ~3k dip ~-6db before the auto eq, which appears to have fixed it with the #6 peak. (clicking on it shows 2.9Khz + 5.7db with a Q of 6.26.
I believe I can also se the target curve to a harman model instead of flat to see hot that sounds.
Open to suggesions on what to tweak or polarity changes that might help reduce the gain required at "point 6"
Manually tweaking the #8 and #2 filters, I can get pretty flat within +/- 3db. This is 12db LR slopes, Tweeter attenuation and the below parametric EQing.
Will listen to this for a while and see what parametric adjustments I might be able to eliminate or combine. Maybe also, I'll switch over to a harman target curve and see what happens. Also, it seems I may have some play in increasing the HF gain as it seems the 1st parametric filter is bringing that all down 12db (pink #1, 183hz, -12db, Q .608)
Will listen to this for a while and see what parametric adjustments I might be able to eliminate or combine. Maybe also, I'll switch over to a harman target curve and see what happens. Also, it seems I may have some play in increasing the HF gain as it seems the 1st parametric filter is bringing that all down 12db (pink #1, 183hz, -12db, Q .608)
Setting gain equal seems to help a fair bit. Same 12db slopes but harman curve target. Will listen to this for a while and play with polarities at the seating position.
Yes it is, and it's a good start... However this presumes that flat is correct and I wouldn't think it is. It also implies that your acoustic mechanical design is perfect, since all depends on this. The need to specifically room EQ can also be a sign of acoustic issues that don't EQ out.
Thanks, I've found the same and switched to a Harman target. Also, I manually EQ's to improve the response and get closer to the curve and reduce the number of EQ points
I suspect the dips/peaks below at 2, 3 and 8 are room issues. Perhaps #8 is suckout where the cross is, I can verify by playing with the xo point and overlap to check.
I suspect the woofer and tweeter rolloff (addressed by low shelf #1) on the low and high end (addressed by #5 bell curve) and the 1.5khz to 5hkz peak addressed by bell curve attenuation #7 are the speakers inherent qualities. Below is the 6db butterworth on both ends.
It's limited as it doesn't have graphs for impulse, waterfall, etc, but much easier to use and you can hear all adjustments in real time with nearly zero delay while music is playing. The RTA-M microphone and software are part of the Driveracks interface, accessible via wifi on an ipad, mac or pc.
By acoustical mechanical design, do you mean the box, baffle, forward alignment, etc?
If so, I'm using the stock cabinet, so not sure of the perfection of the design.
It's a vented box, so perhaps some tuning of the port is possible and I can perhaps add/remove stuffing/bracing. The speakers themselves I recently re-coned, so assuming they are in tip top shape. Tweeters just needed the phase plugs glued but seem to be in great condition.