I would like to start a thread about something we don't quite talk about that often in the sub section ...
and that is SOUND QUALITY
everyone wants a flat FR down to 10hz
( wich noone never gets neway
)
and everyone is looking for 100+db output at sub 40hz!!
( well some do get way more than that with recent projects! ;p )
But what about sound quality in the 0-100hz range???
What should we be expecting in that range of the audio?
Does our earing mechanism enable us to get distortion at this low level ? what is the threshold we are looking for here in distortion?
are there based scintific numbers under wich there is no point in trying to improve quality in sub bass ?
Then, enclosure/design ...
Is the W-OBaffle still the champ in SQ design ?
if not, what is then ?
what are compromises when looking into SQ ..
i'd say that since it's always a balance of everything, we have to let go some SPL and FR to get better SQ right ?
Drivers distortion, is there material ? cause i don't see graphs often when looking at 15+ subs on websites
it's like everybody is almost ignorin the SQ of the drivers when used for sub-bass
what is the best crossover frequency for the sub bass ?
2 way?
3 way ?
i'd say that using a 3-way system , the sub can be let to operate only the seriusly low hz ( 50-70 and lower.. )
but what about using large 15-18" up to 200hz ?
300hz ?
neway, i started this trend cause i want to talk more about SQ in bass....something that we don't mention often
so please add to this thread with your ideas and knowledge about how to get the best possible SQ and it's compromises in low bass
and that is SOUND QUALITY
everyone wants a flat FR down to 10hz
( wich noone never gets neway
)and everyone is looking for 100+db output at sub 40hz!!
( well some do get way more than that with recent projects! ;p )
But what about sound quality in the 0-100hz range???
What should we be expecting in that range of the audio?
Does our earing mechanism enable us to get distortion at this low level ? what is the threshold we are looking for here in distortion?
are there based scintific numbers under wich there is no point in trying to improve quality in sub bass ?
Then, enclosure/design ...
Is the W-OBaffle still the champ in SQ design ?
if not, what is then ?
what are compromises when looking into SQ ..
i'd say that since it's always a balance of everything, we have to let go some SPL and FR to get better SQ right ?
Drivers distortion, is there material ? cause i don't see graphs often when looking at 15+ subs on websites
it's like everybody is almost ignorin the SQ of the drivers when used for sub-bass
what is the best crossover frequency for the sub bass ?
2 way?
3 way ?
i'd say that using a 3-way system , the sub can be let to operate only the seriusly low hz ( 50-70 and lower.. )
but what about using large 15-18" up to 200hz ?
300hz ?
neway, i started this trend cause i want to talk more about SQ in bass....something that we don't mention often
so please add to this thread with your ideas and knowledge about how to get the best possible SQ and it's compromises in low bass
My current take on this at the moment is that it's better to use a sub down low and cross to some woofers above that point, with some decent SD but more modest excursion and more top end.
My feeling is that a good point to cross is around 40 Hz - use subs below that to get brute force excursion and pressurise the room in monopole vented subs - mono with sufficient displacement to get the output. Then above this point cross to some woofers with a low distortion motor and a flat response up to 1khz, but crossed over to mids at say 200 Hz. I think the critical bass for fidelity is actually higher than most subs can handle with finesse - 40 - 200 Hz. There are some that believe that "fast bass" is a matter of getting a good integration of upper bass up into the lower midrange. I believe that the ear is more sensitive above 40 Hz.
So my current take:
1. brute force monopoles up to 40 Hz
2. multiple driver dipole / U frame woofers up to 200 Hz
3. crossing to your preferred mid and tweeter arrangement
I'm considering doing this as my next speaker upgrade, putting my MTMs in open baffle, adding a pair of 10" Peerless CSX per side then my current AV12 subs.
I've tried crossing my AV12s up as high as 80 Hz with a 4LR active xo, but wasn't happy with the result when it comes to acoustic double bass.
My feeling is that a good point to cross is around 40 Hz - use subs below that to get brute force excursion and pressurise the room in monopole vented subs - mono with sufficient displacement to get the output. Then above this point cross to some woofers with a low distortion motor and a flat response up to 1khz, but crossed over to mids at say 200 Hz. I think the critical bass for fidelity is actually higher than most subs can handle with finesse - 40 - 200 Hz. There are some that believe that "fast bass" is a matter of getting a good integration of upper bass up into the lower midrange. I believe that the ear is more sensitive above 40 Hz.
So my current take:
1. brute force monopoles up to 40 Hz
2. multiple driver dipole / U frame woofers up to 200 Hz
3. crossing to your preferred mid and tweeter arrangement
I'm considering doing this as my next speaker upgrade, putting my MTMs in open baffle, adding a pair of 10" Peerless CSX per side then my current AV12 subs.
I've tried crossing my AV12s up as high as 80 Hz with a 4LR active xo, but wasn't happy with the result when it comes to acoustic double bass.
so Paul,
what you are pointing is at more than 40hz quality starts becoming the priority again, and we need to make different arrangement for this to happen.
But a 4 way systems begins to lack the simple attitude though, and is usually twice harder to setup correclty( crossover, number os outputs... ) than a standard 3 way setup nah ?
what do you think about using 18" and more sized subs?
using a fe of them ?
do you believe that the usable freq range of subs goes down on par with their diameter?
if we use the sub higher, doesn't it permit to use a mid woofer that extends usually greater in the upper range?
just a thought.. i know that you have played with subs extensivly so
what you are pointing is at more than 40hz quality starts becoming the priority again, and we need to make different arrangement for this to happen.
But a 4 way systems begins to lack the simple attitude though, and is usually twice harder to setup correclty( crossover, number os outputs... ) than a standard 3 way setup nah ?
what do you think about using 18" and more sized subs?
using a fe of them ?
do you believe that the usable freq range of subs goes down on par with their diameter?
if we use the sub higher, doesn't it permit to use a mid woofer that extends usually greater in the upper range?
just a thought.. i know that you have played with subs extensivly so
My impression of the criteria that leads to the best SQ is the word 'flat':
Flat Bl curve
Flat FR curve
Flat GD curve
Flat Phase curve
Flat THD and IMD curves
Of course, it's impossible to acheive, but keeping those in mind helps in choosing the driver, the amp, the EQ, the box (or IB), the LP filter, etc., etc.
Paul,
It's a very interesting idea. Velo has tried with the 1812 and claims to have found a nightmare crossing the 2 drivers. Seems to possibly be a source of bad measurement results in the latest AVTalk tests (where it looks as though the x-over is at 63ish Hz). Still, I personally think it can work very well. Let us know how it's going if you decide to persue it.
Bosso
Flat Bl curve
Flat FR curve
Flat GD curve
Flat Phase curve
Flat THD and IMD curves
Of course, it's impossible to acheive, but keeping those in mind helps in choosing the driver, the amp, the EQ, the box (or IB), the LP filter, etc., etc.
Paul,
It's a very interesting idea. Velo has tried with the 1812 and claims to have found a nightmare crossing the 2 drivers. Seems to possibly be a source of bad measurement results in the latest AVTalk tests (where it looks as though the x-over is at 63ish Hz). Still, I personally think it can work very well. Let us know how it's going if you decide to persue it.
Bosso
It depends 454Casull.
For example, if you measure the Soundblaster Audigy 4 Pro (which is a very solid soundcard in SQ)...
IMD = 0.0021% which is excellent but...
IMD (15 kHz) = 0.0210% which is less good...
You can get a soundcard like the M-Audio Revolution 7.1 which is probably higher IMD rating but flat across the range because there's no resampling.
I agree with you that most of the time, lower distortion is better.
For example, if you measure the Soundblaster Audigy 4 Pro (which is a very solid soundcard in SQ)...
IMD = 0.0021% which is excellent but...
IMD (15 kHz) = 0.0210% which is less good...
You can get a soundcard like the M-Audio Revolution 7.1 which is probably higher IMD rating but flat across the range because there's no resampling.
I agree with you that most of the time, lower distortion is better.
bobo1on1 said:
True but you have group delay with a bandpass enclosure and group delay is bad.
JinMTVT said:
Yeah open baffle bass is probably the best thing for SQ. Infinite Baffle is good also. The problem is to equalize the response to have enough SPL down low. It's expensive because you want many high excursion woofers.
The best bass / sub quality I've had in my room so far was using my tempest subs from 40Hz down, with 2 x 10" scanspeak drivers per side from 40Hz up. Sounded a lot better than using the tempests up to 80Hz.
I've decided to keep the tempests below 30Hz, and am replacing the scans with 2 labhorns. (home theater - If my system was music only I'd have kept the scans)
Maybe a driver doing 15 - 40Hz has trouble keeping the 40 - 80Hz 'tight ' when its moving so much ?
If I get time I'll try using 2 of my tempests below 30Hz, and 1 from 30 - 80Hz. Maybe the bass will clean up nicely. Won't be for a while though - haven't got the xo to do it at the moment.
Cheers,
Rob
I've decided to keep the tempests below 30Hz, and am replacing the scans with 2 labhorns. (home theater - If my system was music only I'd have kept the scans)
Maybe a driver doing 15 - 40Hz has trouble keeping the 40 - 80Hz 'tight
' when its moving so much ?If I get time I'll try using 2 of my tempests below 30Hz, and 1 from 30 - 80Hz. Maybe the bass will clean up nicely. Won't be for a while though - haven't got the xo to do it at the moment.
Cheers,
Rob
the only problem i see with using a sub up to 40,
and then woofers from 40 up
is that you will end up with either woofers not doing a good job at 1KHZ + or at 80hz less ...
or with another XO near 1KHZ to have mid woofs before the twits.... and a 4 way system quite adds to the complexity of the thing i think ..
it'll be hard to setup, and hard to get right!
( and probably seriously costy )
since we are on a DIY site, and i dind't suggest that no cost was in the line ... we have to consider complexity and cost as up level priority ( after SQ of course in our compromises ;p )
I seriously thought that most 15-18" could play up to 100-200hz
quite nicely ...
what kind of woofers are then used to cross in between 40-80hz region ? size? throw ?
what is the most used range in sub 200hz bass in music?
and by the way ... what are the best quality bass from 100hz up ?
we've only talked about SUB bass for now ..
but i'd still consider the 80-200hz region as "bass"
and then woofers from 40 up
is that you will end up with either woofers not doing a good job at 1KHZ + or at 80hz less ...
or with another XO near 1KHZ to have mid woofs before the twits.... and a 4 way system quite adds to the complexity of the thing i think ..
it'll be hard to setup, and hard to get right!
( and probably seriously costy )
since we are on a DIY site, and i dind't suggest that no cost was in the line ... we have to consider complexity and cost as up level priority ( after SQ of course in our compromises ;p )
I seriously thought that most 15-18" could play up to 100-200hz
quite nicely ...
what kind of woofers are then used to cross in between 40-80hz region ? size? throw ?
what is the most used range in sub 200hz bass in music?
and by the way ... what are the best quality bass from 100hz up ?
we've only talked about SUB bass for now ..
but i'd still consider the 80-200hz region as "bass"
Maybe I should have given more details....
The 10" scans were crossed at 250Hz to my mids...
When I crossed the scans to the tempests at 80 instead of 40Hz the sound got worse.... But would go louder / bigger etc.
""
the only problem i see with using a sub up to 40,
and then woofers from 40 up
is that you will end up with either woofers not doing a good job at 1KHZ + or at 80hz less ...
or with another XO near 1KHZ to have mid woofs before the twits.... and a 4 way system quite adds to the complexity of the thing i think ..
it'll be hard to setup, and hard to get right!
( and probably seriously costy ) ""
Your original post asked about sound quality up to 100Hz... Why the assumption of an xo at 1kHz ? I answered regarding sound quality in low bass
You need to look at the scans + tempests as a 'subwoofer system' rather than a 'sub + bass' situation. ie - it's not a 4-way system, but a 2-way + sub where the sub happens to be a 2-way..if that makes sense
btw I don't see why a 4 - way is more difficult than a 3-way to set up.. as long as you've got basic measuring equipment.
To sum up - in a music only system I'd have kept my 3 x tempests from 10 - 40Hz, my 4 x scanspeak 8565-01 10" from 40 - 80 as a good sound quality bass system. I prefer them to my 3 tempests (10 - 80Hz). If I was doing this as a music system I'd probably cross at 30Hz though rather than 40Hz. (I only give my thoughts on what I've actually heard though) The only reason I'm building labhorns is my penchant for home theater...
Maybe you should set out your goals and the system you intend to put the subs into. Then our suggestions may be more useful.
Cheers,
Rob
The 10" scans were crossed at 250Hz to my mids...
When I crossed the scans to the tempests at 80 instead of 40Hz the sound got worse.... But would go louder / bigger etc.
""
the only problem i see with using a sub up to 40,
and then woofers from 40 up
is that you will end up with either woofers not doing a good job at 1KHZ + or at 80hz less ...
or with another XO near 1KHZ to have mid woofs before the twits.... and a 4 way system quite adds to the complexity of the thing i think ..
it'll be hard to setup, and hard to get right!
( and probably seriously costy ) ""
Your original post asked about sound quality up to 100Hz... Why the assumption of an xo at 1kHz ? I answered regarding sound quality in low bass
You need to look at the scans + tempests as a 'subwoofer system' rather than a 'sub + bass' situation. ie - it's not a 4-way system, but a 2-way + sub where the sub happens to be a 2-way..if that makes sense
btw I don't see why a 4 - way is more difficult than a 3-way to set up.. as long as you've got basic measuring equipment.
To sum up - in a music only system I'd have kept my 3 x tempests from 10 - 40Hz, my 4 x scanspeak 8565-01 10" from 40 - 80 as a good sound quality bass system. I prefer them to my 3 tempests (10 - 80Hz). If I was doing this as a music system I'd probably cross at 30Hz though rather than 40Hz. (I only give my thoughts on what I've actually heard though) The only reason I'm building labhorns is my penchant for home theater...
Maybe you should set out your goals and the system you intend to put the subs into. Then our suggestions may be more useful.
Cheers,
Rob
sorry if i derived from my personal topic
hihih
and also sorry if i turned my posts to look like questions for my personal projects ..wich it was not intended to!
ok so lets get back to the subject ..objectivly!
So from your experience, 2 types of drivers are needed to get the best quality under 100hz for a given system
( with the drivers you used of course ...)
so why do you think your tempests aren't good to work at higher than 40hz on your system ?
have you come to conclusions about the reason?
not fast enough ?
and hwat kind of crossover have you used in between both?
was it steep ? or they were permit to work considreably together???
( sorry if you mentionned alrady the type of crossover slope )
hihih
and also sorry if i turned my posts to look like questions for my personal projects ..wich it was not intended to!
ok so lets get back to the subject ..objectivly!
So from your experience, 2 types of drivers are needed to get the best quality under 100hz for a given system
( with the drivers you used of course ...)
so why do you think your tempests aren't good to work at higher than 40hz on your system ?
have you come to conclusions about the reason?
not fast enough ?
and hwat kind of crossover have you used in between both?
was it steep ? or they were permit to work considreably together???
( sorry if you mentionned alrady the type of crossover slope )
My geuss would be the tempest get louder at the 80Hz end because of increasing radiation impedance.
So the low end is less compared to the upper bass creating an imballance.
This is also a problem of the driver manufaturers. Getting a balance in the bass responce. Using a heavier cone is one way but you lose effeciency.
Also at the higher bass frequencies the internal box geometry also becomes more important
So the low end is less compared to the upper bass creating an imballance.
This is also a problem of the driver manufaturers. Getting a balance in the bass responce. Using a heavier cone is one way but you lose effeciency.
Also at the higher bass frequencies the internal box geometry also becomes more important
The xo @40 Hz was from my av processor, 24dB. I added a 2nd 12dB to my mains to give a total 24dB slope on them (processor puts a 12dB highpass slope when speakers are set to 'small')
The tempests were eq'd flat in room before xo'ing, so played the same spl from approx 15Hz - 120Hz. The 10" scanspeaks were flat in room to 20Hz before xo'ing.
I'm guessing the main reason for sounding better is that the scanspeaks were just a lot higher quality drivers than the tempests. Although if I test the tempests as I said above I'll see if they 'clean up' when they're not doing the sub 30Hz stuff.
I'm not saying you must use 2 drivers to get 'good bass', just giving my experience with the tempests and the scans.
Cheers,
Rob.
The tempests were eq'd flat in room before xo'ing, so played the same spl from approx 15Hz - 120Hz. The 10" scanspeaks were flat in room to 20Hz before xo'ing.
I'm guessing the main reason for sounding better is that the scanspeaks were just a lot higher quality drivers than the tempests. Although if I test the tempests as I said above I'll see if they 'clean up' when they're not doing the sub 30Hz stuff.
I'm not saying you must use 2 drivers to get 'good bass', just giving my experience with the tempests and the scans.
Cheers,
Rob.
Best subs
I agree that servo subs can be among the best. I had a Genesis 900 sub that was pretty good. Genesis informed me that they had a mod to improve the attachment of the accelerometer to the woofer thus reducing distortion. I was skeptical, but sent the woofer off to them. When I got the woofer back into the subwoofer box, I was really, really impressed. The bass was perhaps the best I have heard. This shows how feedback devices can make an average woofer into a very high performer. The only other bass I heard that was better was a Genesis 200 system which had total of 16 eight inch woofers also servo controlled.
I was rolling the Genesis sub off at about 40 hz to Hedlund Horns, which used a Lowther DX4. The midbass of the Lowther driver in a back horn is also something to behold. The very flexible crossover provided by Genesis allowed me to provide a seamless crossover, which I am convinced is the reason why most don't get great bass.
I am playing around with Avalanche Audio 18 inch drivers in an W style open baffle. I have not yet got the system up and running yet, but it will be interesting to see how these drivers work in an open baffle arrangement and whether they can make music rolling them off at around 100 hz.
Retsel
I agree that servo subs can be among the best. I had a Genesis 900 sub that was pretty good. Genesis informed me that they had a mod to improve the attachment of the accelerometer to the woofer thus reducing distortion. I was skeptical, but sent the woofer off to them. When I got the woofer back into the subwoofer box, I was really, really impressed. The bass was perhaps the best I have heard. This shows how feedback devices can make an average woofer into a very high performer. The only other bass I heard that was better was a Genesis 200 system which had total of 16 eight inch woofers also servo controlled.
I was rolling the Genesis sub off at about 40 hz to Hedlund Horns, which used a Lowther DX4. The midbass of the Lowther driver in a back horn is also something to behold. The very flexible crossover provided by Genesis allowed me to provide a seamless crossover, which I am convinced is the reason why most don't get great bass.
I am playing around with Avalanche Audio 18 inch drivers in an W style open baffle. I have not yet got the system up and running yet, but it will be interesting to see how these drivers work in an open baffle arrangement and whether they can make music rolling them off at around 100 hz.
Retsel
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