The reason one woofer sounds better than two in a TMM configuration is called lobing. The lower woofer will have negative interference with the tweeter due to the large center to center distance. It has nothing to do with cone mass or motor strength. For this reason a 2.5-way or MTM configuration is much better sounding than a 2-way TMM.
Also I agree with camplo regarding coil inductance beeing the number one parameter determining woofer transient speed, not cone mass and/or motor strength as believed by many. This has been discussed to death on various forums over the years.
Also I agree with camplo regarding coil inductance beeing the number one parameter determining woofer transient speed, not cone mass and/or motor strength as believed by many. This has been discussed to death on various forums over the years.
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I did finally get the DCX464/ME464 combo up and rolling!
I considered doing an MTM set up as well…having many 15” midwoofers available for this purpose.
In the end I chose to go with a TMM like Mark (sort of). I’ve had the “wall of woofers” setups before, and as fun as they can be, I’ve come to the conclusion they’re just not necessary in my room (fairly well damped at 14.5’ x 28’ x 8.6’).
I prefer a simpler/smaller design nowadays.
With some EQ and crossover work I’m glad I did, it’s really all I needed in this (not large) room of 14.5’ wide X 28’ long X 8.5’ high.
After lots of experimentation with DSP I’ve settled with (for now)-
Bottom woofer (sub) carries 0-100Hz, mid-woofer band-passed at 45-450Hz… both at 24db slope.
For now the CD/horn combination uses B&C’s FB468 passive crossover.
how does it sound ? i assume you use EQ with the FB468 . are you crossing at 450hz ? i would be really curious how well lower crossovers work .
Yes the FB 468 is in line to handle the coax CD.
I then EQ’d the CD alone, then added the midwoofers and subs and finish up the EQ.
The mid-woofers and subs are running off of my crown XLS 1002’s, which have their own crossover capabilities.
My DAC is a minidsp HD, which I use for DSP (duhh!) 😂.
As far as the sound goes, yes I think it sounds great right now, especially with stellar recordings/source material.
Things sounded a bit edgy and grainy when I first got the horns going but I expected that.
When I install new speakers I always use the same procedure after initial DSP-
1- listen for 10 or 15 minutes using the same A side of my favorite album, leave it on repeat and leave the room.
2- come back in a couple of hours and listen to the same A side for 10 or 15 minutes. Leave it on repeat and leave the room.
3- come back in approximately 24 hours and listen to the same A side of the same album.
Most of the time I hear an improvement over time in new loudspeakers in each case.
Listening for only 10 or 15 minutes each time and then leaving the room eliminates the BS (IMO) equation of your ears getting used to the new speakers.
I hope I made some sense LOL..
I then EQ’d the CD alone, then added the midwoofers and subs and finish up the EQ.
The mid-woofers and subs are running off of my crown XLS 1002’s, which have their own crossover capabilities.
My DAC is a minidsp HD, which I use for DSP (duhh!) 😂.
As far as the sound goes, yes I think it sounds great right now, especially with stellar recordings/source material.
Things sounded a bit edgy and grainy when I first got the horns going but I expected that.
When I install new speakers I always use the same procedure after initial DSP-
1- listen for 10 or 15 minutes using the same A side of my favorite album, leave it on repeat and leave the room.
2- come back in a couple of hours and listen to the same A side for 10 or 15 minutes. Leave it on repeat and leave the room.
3- come back in approximately 24 hours and listen to the same A side of the same album.
Most of the time I hear an improvement over time in new loudspeakers in each case.
Listening for only 10 or 15 minutes each time and then leaving the room eliminates the BS (IMO) equation of your ears getting used to the new speakers.
I hope I made some sense LOL..
Yes the FB 468 is in line to handle the coax CD.
I then EQ’d the CD alone, then added the midwoofers and subs and finish up the EQ.
The mid-woofers and subs are running off of my crown XLS 1002’s, which have their own crossover capabilities.
My DAC is a minidsp HD, which I use for DSP (duhh!) 😂.
As far as the sound goes, yes I think it sounds great right now, especially with stellar recordings/source material.
Things sounded a bit edgy and grainy when I first got the horns going but I expected that.
When I install new speakers I always use the same procedure after initial DSP-
1- listen for 10 or 15 minutes using the same A side of my favorite album, leave it on repeat and leave the room.
2- come back in a couple of hours and listen to the same A side for 10 or 15 minutes. Leave it on repeat and leave the room.
3- come back in approximately 24 hours and listen to the same A side of the same album.
Most of the time I hear an improvement over time in new loudspeakers in each case.
Listening for only 10 or 15 minutes each time and then leaving the room eliminates the BS (IMO) equation of your ears getting used to the new speakers.
I hope I made some sense LOL..
I then EQ’d the CD alone, then added the midwoofers and subs and finish up the EQ.
The mid-woofers and subs are running off of my crown XLS 1002’s, which have their own crossover capabilities.
My DAC is a minidsp HD, which I use for DSP (duhh!) 😂.
As far as the sound goes, yes I think it sounds great right now, especially with stellar recordings/source material.
Things sounded a bit edgy and grainy when I first got the horns going but I expected that.
When I install new speakers I always use the same procedure after initial DSP-
1- listen for 10 or 15 minutes using the same A side of my favorite album, leave it on repeat and leave the room.
2- come back in a couple of hours and listen to the same A side for 10 or 15 minutes. Leave it on repeat and leave the room.
3- come back in approximately 24 hours and listen to the same A side of the same album.
Most of the time I hear an improvement over time in new loudspeakers in each case.
Listening for only 10 or 15 minutes each time and then leaving the room eliminates the BS (IMO) equation of your ears getting used to the new speakers.
I hope I made some sense LOL..
We have more in common, I've got crown cts amps with usp4 dsp cards...
Ears operate like eyes in the sense that they seek to adjust input to bring input to a certain level whether raising or lowering input sensitivity....just like going into a the sun from the dark and from the sun to the dark....ears will seek to balance incoming input, giving them a rest period allows for a reset.
Also consider anything different than what you are used to sounds off sometimes and takes a while to accept as the new norm.
Ears operate like eyes in the sense that they seek to adjust input to bring input to a certain level whether raising or lowering input sensitivity....just like going into a the sun from the dark and from the sun to the dark....ears will seek to balance incoming input, giving them a rest period allows for a reset.
Also consider anything different than what you are used to sounds off sometimes and takes a while to accept as the new norm.
Fully agree with points re MTM, 2.5, and 2-way TMM.
The 2-way TMM simply fails due to woofer-tweeter lobing.
My take on inductance has been that inductance limits the high frequency end of a sub's response.
My take on motor strength vs mass is that it limits the lower end response, in particular the dynamics of the lower end.
Do you think inductance is a factor at the lower end too, more so than motor strength to mass ?
Hi Mark,
this excellent Adire Audio paper explains woofer speed, definitely worth a read;
http://www.diy-audio.narod.ru/litr/WooferSpeed.pdf
"There's a common misconception out there that heavy woofers must be "slow", and light woofers must be "fast". There's also this concept that the "acceleration factor" (BL/Mms) is an indicator of woofer speed/transient response. High BL, combined with a low Mms, should give great transient response, right? Well, on surface these might sound like logical assumptions. However, they are in fact incorrect! More to the point, moving mass has precious little to do with woofer speed or signal response!"
Hi Lament, thanks for that paper.
I need to study it more, but my first take reading the experiment that doubles the mass of the driver, is that the study is geared towards the mass-added effects on high frequency response.
And the results matched my (meager) understanding... that mass has relatively little effect there compared to inductance.
Where i still think BL/mass matters, is when looking at low frequency response alone....say when a sub is low passed at 100Hz.
IOW, a bandwidth filtered impulse response, that doesn't care about high frequency response because the high frequency response needed for transient response comes from other drivers.
So i just want to know how strong is a sub at being just a sub..
Maybe this is audio myth too, but it seems to me BL/mass ends up being more a factor of excursion capability than anything else.
Ready and willing to learn if thinking incorrectly.
I need to study it more, but my first take reading the experiment that doubles the mass of the driver, is that the study is geared towards the mass-added effects on high frequency response.
And the results matched my (meager) understanding... that mass has relatively little effect there compared to inductance.
Where i still think BL/mass matters, is when looking at low frequency response alone....say when a sub is low passed at 100Hz.
IOW, a bandwidth filtered impulse response, that doesn't care about high frequency response because the high frequency response needed for transient response comes from other drivers.
So i just want to know how strong is a sub at being just a sub..
Maybe this is audio myth too, but it seems to me BL/mass ends up being more a factor of excursion capability than anything else.
Ready and willing to learn if thinking incorrectly.
I chose to take the safe route and my mid 15 is near 70 grams...
I've read enough to know that there is a connection between a light cone and accuracy regardless of what a measurement shows...it was some brand of woofer with super light diaphragms that were upheld as being able to recreate musical instruments with realism..
I'd rather see some scientific evidence of course....unfortunately I have never seen such comments said about a woofer with a heavy cone...
I've read enough to know that there is a connection between a light cone and accuracy regardless of what a measurement shows...it was some brand of woofer with super light diaphragms that were upheld as being able to recreate musical instruments with realism..
I'd rather see some scientific evidence of course....unfortunately I have never seen such comments said about a woofer with a heavy cone...
Interesting!
Perhaps not related- I was in shock at the more realistic sound of a kick drum sample going from a two way (midwoofer/tweeter horn) loudspeaker to a three way (woofer, midrange horn, tweeter horn/).
Perhaps that’s just a horn thing.
Ive also noticed a kick drum sample low passed at 250hz. has no guts compared to the same sample passed at 1000hz.
Perhaps not related- I was in shock at the more realistic sound of a kick drum sample going from a two way (midwoofer/tweeter horn) loudspeaker to a three way (woofer, midrange horn, tweeter horn/).
Perhaps that’s just a horn thing.
Ive also noticed a kick drum sample low passed at 250hz. has no guts compared to the same sample passed at 1000hz.
I think 2-way to 3-way is about dividing up the spectrum to make more SPL, with greater low end frequency extension.
One of the first audio light bulbs that went off in my head,
is that transient response equals frequency response.
It takes full range frequency response to have great transient response, the flatter the better (for transients)
And if you want big SPL and transient response beginning from low freq extension, hello multi-way
Once that flat frequency response full-range 20-20K with SPL is met,
the only way to improve transient response further ime is through improved timing.....ie flatten phase, particularly down low.