Punch and Low Bass
Wright,
Several issues to consider, but low bass, high efficiency, and enclosure size are closely interrelated. The simple solution to retain a reasonable enclosure size is to use less efficient drivers and more power. But, headroom is still needed.
The same holds true for designing a driver. Efficiency, excursion, Bl curves, and Qs are interrelated to the extent that to gain one thing you usually lose something else, making it difficult to achieve high efficiency, medium Qs, high excursion, low Vas and Fs all in the same subwoofer package. But every year it gets better and Adire has made big improvements.
Low inductance, too, is all important for good transient response/ acceleration (poorly named "fast bass") and lower distortion. This is nearly as important as the tuning Q of the enclosure, IMO.
Sretin
WRT punch, the fundamental has to have impact for realism, at whatever the frequency. Dynamics. Most pro sound rigs didn't go below 40 Hz, although this is changing, but still did kick drums well. Smack in the chest well.
The other part of the point was the high frequency portion of the signal. Try playing just your sub while listening to kick drum. There is no "edge" to the impact - just a muffled facsimile. You need to reproduce the high freq components to get the punch right. So, even if the fundamental falls below the crossover, a good deal of information needs to reproduced accurately above the crossover for the "event" to sound right. Phase needs to be maintained through the crossovers.
The really curious thing I have found is that people seem to gravitate toward musical tastes best displayed by, but also limited to, what their system does well. Whether unintentionally or by design, owners of 6.5" 85 dB two-ways yield up a big collection of "little girl with guitar" CDs followed by jazz trios. They may not even realize they have imposed limits on their own enjoyment.
I like "Trinity Sessions" too. Try "Five Days in July"
Tim
Wright,
Several issues to consider, but low bass, high efficiency, and enclosure size are closely interrelated. The simple solution to retain a reasonable enclosure size is to use less efficient drivers and more power. But, headroom is still needed.
The same holds true for designing a driver. Efficiency, excursion, Bl curves, and Qs are interrelated to the extent that to gain one thing you usually lose something else, making it difficult to achieve high efficiency, medium Qs, high excursion, low Vas and Fs all in the same subwoofer package. But every year it gets better and Adire has made big improvements.
Low inductance, too, is all important for good transient response/ acceleration (poorly named "fast bass") and lower distortion. This is nearly as important as the tuning Q of the enclosure, IMO.
Sretin
WRT punch, the fundamental has to have impact for realism, at whatever the frequency. Dynamics. Most pro sound rigs didn't go below 40 Hz, although this is changing, but still did kick drums well. Smack in the chest well.
The other part of the point was the high frequency portion of the signal. Try playing just your sub while listening to kick drum. There is no "edge" to the impact - just a muffled facsimile. You need to reproduce the high freq components to get the punch right. So, even if the fundamental falls below the crossover, a good deal of information needs to reproduced accurately above the crossover for the "event" to sound right. Phase needs to be maintained through the crossovers.
The really curious thing I have found is that people seem to gravitate toward musical tastes best displayed by, but also limited to, what their system does well. Whether unintentionally or by design, owners of 6.5" 85 dB two-ways yield up a big collection of "little girl with guitar" CDs followed by jazz trios. They may not even realize they have imposed limits on their own enjoyment.
I like "Trinity Sessions" too. Try "Five Days in July"
Tim
Re: Punch and Low Bass
I think this is a bit too much over a simplification and not a fair comment to make. I have lived with three speakers with 6.5" mid/bass, first Tannoy M2's first model, then Mission 752 freedoms and then peerless 850467's. None of these restricted any music I listened to from classical to hard hitting stuff with lots of bass and clout in them. They all produced plenty of bass to satisfy and went loud enough.
I now have a three way which again has about 85dB sens but reaches out much further dwn wards curtasy of a pair of XLS, but I listen to exactly the same music then as I do now.
Having two way smallish speakers does not IMO pidgeon hole you into any particular genre of music. You could argue that 6.5" et al will produce most faithfully to the original simple little g guitar stuff, but that does not mean everything else cannot be enjoyed either, far from it I enjoyed every minute with my 6.5" speakers most of which was NOT little G stuff.
Tim Moorman said:
I think this is a bit too much over a simplification and not a fair comment to make. I have lived with three speakers with 6.5" mid/bass, first Tannoy M2's first model, then Mission 752 freedoms and then peerless 850467's. None of these restricted any music I listened to from classical to hard hitting stuff with lots of bass and clout in them. They all produced plenty of bass to satisfy and went loud enough.
I now have a three way which again has about 85dB sens but reaches out much further dwn wards curtasy of a pair of XLS, but I listen to exactly the same music then as I do now.
Having two way smallish speakers does not IMO pidgeon hole you into any particular genre of music. You could argue that 6.5" et al will produce most faithfully to the original simple little g guitar stuff, but that does not mean everything else cannot be enjoyed either, far from it I enjoyed every minute with my 6.5" speakers most of which was NOT little G stuff.
Small speakers-Big speakers
Just an observation about the types of CDs played. I listen to them, too. But that's not all I listen to.
There are all manner of good sounding small speakers. I have no problem with people staying with whatever gives them pleasure.
I've heard a few myself including the small Fostex drivers that were amazing in many respects.
I just think that size need not always be restricted to small two-ways because they are convenient or popular. Builders with space might actually better enjoy big dynamics and low bass extension in a large well designed 3-way...Or a design employing high quality pro drivers - even horns.
Good sound can be done in many ways. It is nice to see experimentation done in a variety of designs with fresh approaches. Keeps people interested in improving their systems, attract newcomers with the desire to DIY .
Tim
Just an observation about the types of CDs played. I listen to them, too. But that's not all I listen to.
There are all manner of good sounding small speakers. I have no problem with people staying with whatever gives them pleasure.
I've heard a few myself including the small Fostex drivers that were amazing in many respects.
I just think that size need not always be restricted to small two-ways because they are convenient or popular. Builders with space might actually better enjoy big dynamics and low bass extension in a large well designed 3-way...Or a design employing high quality pro drivers - even horns.
Good sound can be done in many ways. It is nice to see experimentation done in a variety of designs with fresh approaches. Keeps people interested in improving their systems, attract newcomers with the desire to DIY .
Tim
I ain't no expert, but I've kind of gotten around this "Q" thing.
"Critically damped" means the same thing as Q=1/2. It does not mean Q=.707, as one said, nor Q=1/2 or less, as another said.
Q is a measure of how resonant a system is. It is a ratio of stored energy to dissipated energy, with a factor of 2 thrown in to make some calculation or another come out right. We measure Q at the system's fundamental resonant frequency.
Here's a physical example: Imagine a door with a spring on it to pull it closed. One of those swinging saloon doors that goes "broing broing broing" back and forth when a cowboy goes through it has a high Q. A door to an office building that has one of those shock-absorber things on it to make it close very slowly has a low Q - well under 1/2.
Now pull an imaginary door open and let it swing shut. If it overshoots like the saloon door, it has a Q over 1/2. If it does not overshoot, it has a Q of 1/2 or less. A "critically damped" door would be one that closed without overshooting (or going thud), but did so as fast as possible.
"Critically damped" means the same thing as Q=1/2. It does not mean Q=.707, as one said, nor Q=1/2 or less, as another said.
Q is a measure of how resonant a system is. It is a ratio of stored energy to dissipated energy, with a factor of 2 thrown in to make some calculation or another come out right. We measure Q at the system's fundamental resonant frequency.
Here's a physical example: Imagine a door with a spring on it to pull it closed. One of those swinging saloon doors that goes "broing broing broing" back and forth when a cowboy goes through it has a high Q. A door to an office building that has one of those shock-absorber things on it to make it close very slowly has a low Q - well under 1/2.
Now pull an imaginary door open and let it swing shut. If it overshoots like the saloon door, it has a Q over 1/2. If it does not overshoot, it has a Q of 1/2 or less. A "critically damped" door would be one that closed without overshooting (or going thud), but did so as fast as possible.
I must confess that I haven't read all of this thread, but one must realize that "tight" means different things to different people..
Qtc (nor group delay or anything people claim as a metric) is not the main effect, IMO.
I have always heard people talk of speakers with "tight" bass. These speakers sometimes had a maximally flat Q, but more often they had a Q of 1+ - one had a Q of 1.3. I would say that it is more correct to say that "tight" bass is merely bass that satisfies ones' preconceived notions of "good" bass.
BTW, the analogy with swinging doors may appear to be intuitive, but swinging is a displacement phenomena (keep your dirty mind to yourself ;-) and SPL or sound have to do with acceleration. Even Qtc =0.5 speakers have step displacement overshoot....
Qtc (nor group delay or anything people claim as a metric) is not the main effect, IMO.
I have always heard people talk of speakers with "tight" bass. These speakers sometimes had a maximally flat Q, but more often they had a Q of 1+ - one had a Q of 1.3. I would say that it is more correct to say that "tight" bass is merely bass that satisfies ones' preconceived notions of "good" bass.
BTW, the analogy with swinging doors may appear to be intuitive, but swinging is a displacement phenomena (keep your dirty mind to yourself ;-) and SPL or sound have to do with acceleration. Even Qtc =0.5 speakers have step displacement overshoot....
kelticwizard said:
I don't know what to say about posts #31 and #33, but I believe no overshoot is the definition of "critical" in this context. The great web offers support:
http://www.hep.ph.ic.ac.uk/CMS/UG/Vibrations+Waves/damped/critical_damping.html
Dave Jones said:
Here's another one:
http://www.techmfg.com/TechBackground/techbkgd_2.html
I think the pictures in 31 and 33 probably denote SPL (or acceleration) rather than cone displacement.
[Added later: I missed your first reply, where you used the words "SPL" and "acceleration." We are on the same page.]
Ron E said:
I tend to agree with this opinion. I stated a long time ago, ( in this thread or another similar one), that what people think of as tight, fast, etc. bass is merely a presence peak at around 60 to 80 Hz, common in all PA systems, most domestic hi-fi, and even sometimes as part of the mastering process...
Ron E said:
Well I'd suggest this is a total misuse of the word "tight".
All the high Q designs I've heard do not sound remotely tight.
The bass end is fat and rolling, the speakers sounds like it
has "good" bass, but I'd suggest it doesn't.
Highish Q sealed box loading makes the bass end obvious and
difficult to ignore, whilst at the same time genuine extension
in room can be poor due to a less than ideal room match.
sreten.
It also depends somewhat which speaker you are using. If the driver in a High Q system will go down low then I would imagine it could make the system sound how sreten mentioned. However if the driver used cant go that low in a sealed enclosure, ie it has an f3 of about 70-80hz then a high Q doesnt sound bad at all because it doesnt output enough at lower frequencies to sound "wallowy" etc. This would probably sum up most domestic hifi speakers using 6.5" drivers. They dont actually play that low in room anyway so a high Q wont sound bad because where you really notice bad quality bass is not produced.
Although not quite as higher Q as those mentioned a sealed pair ive made have a Q of about 1.05, these sound fine but have to be positioned correctly. Anywhere near a wall and they sound terrible and do boom. They have fully comp BSC so thats not entirely surprising but in free space they really do sing.
Now off to making somr open baffles to try something out.
Although not quite as higher Q as those mentioned a sealed pair ive made have a Q of about 1.05, these sound fine but have to be positioned correctly. Anywhere near a wall and they sound terrible and do boom. They have fully comp BSC so thats not entirely surprising but in free space they really do sing.
Now off to making somr open baffles to try something out.
5th element said:
Sorry but absolutely the opposite. The high Q designs
I referred to are normal compact speakers which make
a real mess of the 50Hz to 100Hz region. (I play bass)
Poor placement only makes things worse, but even with
optimum placement not ideally aligned for room gain.
(Still miles better than a maximally flat reflex design)
Overdamped reflex's emulating the response of low Q
sealed boxes in the most effective route to "tight" bass.
Low Q sealed boxes are even better, but rather large.
sreten.Hi, Bessel is .58.
A Qts of .5 is critically damped. But if .707 is Butterworth and .58 is Bessel, are there "names" for .5 and 1. (Chebychev for instance)??
Qts is comprised of the electrical and mechanical Qs of the driver.
Qtc, which this decades old thread was discussing, is the value of the driver when enclosed.
A driver/cabinet Qtc response could look similar to filters of named values, that is, Bessel filters have an overall Q of .58, Butterworth filters have an overall Q of .7, and Chebyshev filters have Q's of 1 or more.
Since Qtc can range from over 6 to under .5, assigning them dead scientist's filter names has rather limited academic use.
And yet here I am learning from it today.
I just read this entire topic and just want to say thanks!
Im about to build two sealed subs using Acoustic Elegance AV15H-4 drivers. QTC of 0.707 is not feasible for these drivers as that alignment yields an impossibly small box.
Now, I’m going back and forth in my mind between QTC of 0.5 and 0.6
Can anyone give me guidance on which box to commit to?
Which one will yield tight, fast bass? For context, my mains are YG Acoustics Carmel v1 which should throw some light on my definition of “tight” and “fast”
I just read this entire topic and just want to say thanks!
Im about to build two sealed subs using Acoustic Elegance AV15H-4 drivers. QTC of 0.707 is not feasible for these drivers as that alignment yields an impossibly small box.
Now, I’m going back and forth in my mind between QTC of 0.5 and 0.6
Can anyone give me guidance on which box to commit to?
Which one will yield tight, fast bass? For context, my mains are YG Acoustics Carmel v1 which should throw some light on my definition of “tight” and “fast”
Hmm, assuming the below specs are current, then I calc a ~40 L net box, so add the driver's displacement and it seems to fit with some room to spare, though as small as it is it will need a good bit of [removable] added mass perched on top and/or massive base.
Technically, 0.5 is transient perfect, which defines the exact tracking of the signal's 'attack'/'decay' or at least as close as one can get with a point source driver whereas compression horns can come much closer, but down low the room dominates and in my case never followed the theoretical 2nd order rise below the room's 1st mode, so historically I've tuned various well damped vented alignments down into it [very low Fb/p, i.e. < 0.5 Qt, AKA custom 'shelf'/EBS alignments] to compensate to get a nominally flat in room response.
To me then, 'tight'/'fast' = a more rapid 'attack'/'decay' [over damped] whereas 'fast' = a rising response variant of 'tight' or just that the XO has a longer 'decay' = very wide BW, i.e. has a lower slope order such as a 1st order Vs a higher one, though to most folks it just implies a wider [HF] BW, so frankly wish folks would quit using it or at least define what they mean.
Regardless, there's not enough difference for most folks to notice in room other than its impact on performance, so your call.
https://www.diyaudio.com/community/...-from-acoustic-elegance-former-stryke.131172/
AV15-H
FS: 22Hz
Qms: 4.86
Vas: 197L
Cms: .22mm/N
Mms: 235g
Rms: 6.7
Xmax: 23mm
Xmech: 32mm
Sd: 794sqcm
Vd p-p: 3.67L
Qes: .29
Re: 2.7ohm
Le: .28mH
Z: 4ohm
Bl: 17.6Tm
Pe: 1000W
Qts: .27
qWSPL: 90.7db
2.83V: 95.5dB
Technically, 0.5 is transient perfect, which defines the exact tracking of the signal's 'attack'/'decay' or at least as close as one can get with a point source driver whereas compression horns can come much closer, but down low the room dominates and in my case never followed the theoretical 2nd order rise below the room's 1st mode, so historically I've tuned various well damped vented alignments down into it [very low Fb/p, i.e. < 0.5 Qt, AKA custom 'shelf'/EBS alignments] to compensate to get a nominally flat in room response.
To me then, 'tight'/'fast' = a more rapid 'attack'/'decay' [over damped] whereas 'fast' = a rising response variant of 'tight' or just that the XO has a longer 'decay' = very wide BW, i.e. has a lower slope order such as a 1st order Vs a higher one, though to most folks it just implies a wider [HF] BW, so frankly wish folks would quit using it or at least define what they mean.
Regardless, there's not enough difference for most folks to notice in room other than its impact on performance, so your call.
https://www.diyaudio.com/community/...-from-acoustic-elegance-former-stryke.131172/
AV15-H
FS: 22Hz
Qms: 4.86
Vas: 197L
Cms: .22mm/N
Mms: 235g
Rms: 6.7
Xmax: 23mm
Xmech: 32mm
Sd: 794sqcm
Vd p-p: 3.67L
Qes: .29
Re: 2.7ohm
Le: .28mH
Z: 4ohm
Bl: 17.6Tm
Pe: 1000W
Qts: .27
qWSPL: 90.7db
2.83V: 95.5dB
Thank you GM
I had to find out what an EBS alignment was. I found an old post of yours:
https://www.diyaudio.com/community/threads/calculating-an-ebs-alignment.17460/post-203380
This is another rabbit hole to go explore.
I had to find out what an EBS alignment was. I found an old post of yours:
https://www.diyaudio.com/community/threads/calculating-an-ebs-alignment.17460/post-203380
This is another rabbit hole to go explore.