Which roll off would have better transients the vented or sealed? I mean, how do we tell how a roll off effects transients?
Essentially, I am looking at making a sealed cab and crossing over anywhere above 100hz as my subs play clean up to 180hz without boominess. I am just curious if its worth putting port in it to plug and have as a secondary option as they are about the same size. The vented is larger but I will be making a larger sealed cab anyway, to hit a lower QTC.
I am looking for maximum transients and punch. The driver is the Deltalite 2 2515.
Essentially, I am looking at making a sealed cab and crossing over anywhere above 100hz as my subs play clean up to 180hz without boominess. I am just curious if its worth putting port in it to plug and have as a secondary option as they are about the same size. The vented is larger but I will be making a larger sealed cab anyway, to hit a lower QTC.
I am looking for maximum transients and punch. The driver is the Deltalite 2 2515.
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Transient response is related to group delay and the readers digest on that is delay is longer at lower frequencies with all types of enclosures. There are lots of discussions on this out there on the web and the accepted wisdom is that sealed subs are better because they have the lowest group delay, but what many ignore is that after a sealed box is EQ'd to produce the same response as ported the group delay is almost the same as ported, because EQ also adds group delay.
Also related to transient response is motor strength and when it comes to that pro sound drivers and NEO drivers in particular have stronger motors than other versions so you're in really good shape there. Coupled with that is moving mass which is generally lighter with non sub type drivers.
So bottom line to all this is if your box isn't going to see much content below 80-100hz either box design will work equally well but ported would be the most versatile.
Also related to transient response is motor strength and when it comes to that pro sound drivers and NEO drivers in particular have stronger motors than other versions so you're in really good shape there. Coupled with that is moving mass which is generally lighter with non sub type drivers.
So bottom line to all this is if your box isn't going to see much content below 80-100hz either box design will work equally well but ported would be the most versatile.
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Bill Fitzmaurice has been advocating what you have said about the EQ on techtalk, and I agree after experimenting with subs, once you bass boost the transient response changes. He takes it a step further by also saying that there is no such thing as fast bass(I hope I have understood him correctly), but I have experimented with sealed subs reducing the QTC and geez it makes a massive difference in transients.
I have also heard about the group delay and even this concept is disputed by many, but I understand how it does give an idea of how the transients might play out. I always prefer sealed cause the the vented chuffing noise already gives you the illusion that the bass is lagging.
And I also understand there are many other variables such as motor strength of the driver and if you essentially cut of the lower frequencies then your getting better transients anyway. But lets be honest, you can still get superb transients in comparing mid woofers.
Appreciate the advice about the Neo drivers I hope they bode well with my .45 QTC Dayton RSS315HO.
I think adding the ports which I can plug will give me more room to play with and I can get the best of both worlds. The ported gives me some more extension and I can see how they play without subs. And plugged with subs should also sound great.
I have also heard about the group delay and even this concept is disputed by many, but I understand how it does give an idea of how the transients might play out. I always prefer sealed cause the the vented chuffing noise already gives you the illusion that the bass is lagging.
And I also understand there are many other variables such as motor strength of the driver and if you essentially cut of the lower frequencies then your getting better transients anyway. But lets be honest, you can still get superb transients in comparing mid woofers.
Appreciate the advice about the Neo drivers I hope they bode well with my .45 QTC Dayton RSS315HO.
I think adding the ports which I can plug will give me more room to play with and I can get the best of both worlds. The ported gives me some more extension and I can see how they play without subs. And plugged with subs should also sound great.
Relative too higher frequencies this is a fact.
The wavelength of sound at 20khz is 0.678", at 20hz the wavelength is 678". The speed of sound in air at any given moment is the same for all frequencies so it takes 1000 times longer for a single wavelength to propagate at 20hz versus 20khz.. hence... "no such thing as fast bass". It's simply not possible to generate low frequencies as fast as highs so some lag is unavoidable.
That is a poor enclosure design, the port is undersized for the drivers output capability. Take a look at any recent Pro audio subwoofer that uses a high excursion driver, the ports are massive.
Yes absolutely. Is this your first build with Pro drivers?
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Yes it is my first Pro drivers build. I have chosen to emulate the econowave, to a certain extent, hence my choice of the B&C DE250 and B52PHRN waveguide. I know that there is better choice with the waveguide but at $10 a pop it was a bargain. Unless you outright object, I think I will go with the B52?
I also know that the 2515 has not been moulded with the DE250 and that the 12 inch Deltalite was probably a better choice, but I am really keen on 15'' for the punch and slam and as I will be using DSP if all else is done right it should tie everything together well. Minus a perfect spectrogram and directivity index. That would also be great, but apparently the B52 isn't the best match for the 2515.
I have two options at hand using digital crossovers with Audiolense DSP or using a active crossover(DBX234xl) and then using the DSP to flatten the frequency curve and time align. I can see which one works better and experiment. Either way I will be bi-amping.
I am using a front baffle more similar to the Fusion 15 but if I decide to go with the ports I will but them on the back.
I am considering using 2 3inch ports with a 100 litre volume at about a 20cm port length and it is very similar to the closed box roll off. The closed box at a 100 litres gives me approximately .65 QTC. So I can essentially plug the ports if need be. Obviously better group delay with the sealed. I don't know if this is worth is but like you said gives me versatility.
I am getting a 34ms peak with port air velocity is that okay? What is the range I should aim for?
If I am on the wrong track for anything please feel free to let me know.
My goal is articulate, tight, transient bass hence the low QTC for a midbass cab I think any lower will end up being to dry, especially when the drivers have descent motor strength.
I also know that the 2515 has not been moulded with the DE250 and that the 12 inch Deltalite was probably a better choice, but I am really keen on 15'' for the punch and slam and as I will be using DSP if all else is done right it should tie everything together well. Minus a perfect spectrogram and directivity index. That would also be great, but apparently the B52 isn't the best match for the 2515.
I have two options at hand using digital crossovers with Audiolense DSP or using a active crossover(DBX234xl) and then using the DSP to flatten the frequency curve and time align. I can see which one works better and experiment. Either way I will be bi-amping.
I am using a front baffle more similar to the Fusion 15 but if I decide to go with the ports I will but them on the back.
I am considering using 2 3inch ports with a 100 litre volume at about a 20cm port length and it is very similar to the closed box roll off. The closed box at a 100 litres gives me approximately .65 QTC. So I can essentially plug the ports if need be. Obviously better group delay with the sealed. I don't know if this is worth is but like you said gives me versatility.
I am getting a 34ms peak with port air velocity is that okay? What is the range I should aim for?
If I am on the wrong track for anything please feel free to let me know.
My goal is articulate, tight, transient bass hence the low QTC for a midbass cab I think any lower will end up being to dry, especially when the drivers have descent motor strength.
Greetings guys,
I'm not a specialist but if muic related, transcient is often refered to short time events in a music piece. I believe there is two ways perceving it:
: sudenly higher frequencies are involved in a more or less time windows. higher frequencies is meaning shorter wave lengths. The drivers have to move faster and fast enough to reproduce the original event if well reccorded -quality of th mic and reccording chain-
: sudenly there is a spl rise/peak in a short time window that is called "dynamic". the shorter the time window between the lowest spl and the highest spl before the program comes back to the average low spl is often called "transcient". The driver if reproducing equally the original event will be increase its fastness to reach the exercusion needed to acheive the highest spl peak (short time movement).
That means the lowest the surface of the transducter and the highest the spl to reproduce in this time window -aka the transcient- reproduce, the fastest the cone/dome/diag. has to move. Why ? It has to "move" more air to acheive the highest spl note of the transcient vs the higher surface to "move" - presurize" the air.
If the driver and the amp can do it both a little surface or higher surface driver will do. The littlier driver will need more power to reach the spl peak. the voice coil will eventually get too much hot at a point if no cooled and that will introduce taming and limitation in the spl, eventually break if the Xmech is reached. Also more distorsion when coming close to X-max.
For the very few I believe to have or not understood about horns : the impedance adaptation between the cone surface and the air of the room is more progressive and that helps the driver - such an input certainly a massive shortcut- But that's important cause for a driver the larger frequencies windows and the higher spl it has to reproduce in a short time, the more it will have coplex break-ups that give hard time to the reproduction fidelity : distorsion, micro spl dynamic mismatch - hence the love of ESL for micro details and acurate transcient-. The lower the cone surface the more difficult
For a sealed, that means a Qtc of 0.5 to have a transcient perfect speaker.
For vented, the group delay for some can not be heard, what is heard is the noise of the vents and perhaps the fact that this noise is lasting more than the orginal program. But I don't know...many sources don't argue the same. And DSP can solve that in digital FIR domain if one find it to be an important factor to him. However the vents and the room are certainly more the culprits to work on.
For a vented design many noticed a better subjective transcient and subjective hability when the box resonance is tunned above the driver resonance. Which is reducing the -f3. Trade off !
One can understand the importance of the amp & driver size in that purpose for the lowest frequencies to control the driver and to stop it without cone oscilations & break-ups -loaded energy- when playingback.
If the PA event is in a little venue, the room modes will hurt more than everything, the listening position is ruled by many bouncings, echos : playback reproduction is hurted cause the time delays of the notes are not comming at the same time. Rooms matter the most. Imagine a 20 eters wave length and you are at 10 meter of the speakers : you will have no problem of transcient if the speaker/amp can do it : most of the time it can. I.e. the first 10 meter of the 20 meter wave length will arrive for its main in the acurate time windows BUT you will hear he rest of the wave length : the last 10 meters after bouncings in the venues and a part of the first 10 meters after the direct radiation heard cause a part has met the floor, the walls, the chairs, the ceilling.
In the speaker choice, the T&S parameters help to make the work easier for bass : the lowest Le you can choose. The higher Qm you can choose, the lowest Qe you can choose -for vented design- and the higher Sd you can - 18" seems a limit when talking about acurate transcient. Then the mmd/qts ratio.
The Vas and the size of the speaker should NEVER be a problem : no trade off here.
To sumarize : sealed : the cone moves twice more than vented but it's easier to acheive transcient perfect alignment and the noise of the port not exesting you haven't a part of the signal that arrive after the main signal - room factor and placent is more important than with sealed designs- open bafle : the driver will move even more so will have to move faster which is producing more heat in the voice coil - and the size of the bafle hs to be huge to have not DSP -Linkwitz transform- in the low end when talking about bass. But each time the driver will move fast enough if it can and the amp can to reproduce the transcient needed.
I don't knoww if all is acurate here but that's how I understand it and hope that helps. If wrong inputs feel free to correct or ad precisions 🙂
I'm not a specialist but if muic related, transcient is often refered to short time events in a music piece. I believe there is two ways perceving it:
: sudenly higher frequencies are involved in a more or less time windows. higher frequencies is meaning shorter wave lengths. The drivers have to move faster and fast enough to reproduce the original event if well reccorded -quality of th mic and reccording chain-
: sudenly there is a spl rise/peak in a short time window that is called "dynamic". the shorter the time window between the lowest spl and the highest spl before the program comes back to the average low spl is often called "transcient". The driver if reproducing equally the original event will be increase its fastness to reach the exercusion needed to acheive the highest spl peak (short time movement).
That means the lowest the surface of the transducter and the highest the spl to reproduce in this time window -aka the transcient- reproduce, the fastest the cone/dome/diag. has to move. Why ? It has to "move" more air to acheive the highest spl note of the transcient vs the higher surface to "move" - presurize" the air.
If the driver and the amp can do it both a little surface or higher surface driver will do. The littlier driver will need more power to reach the spl peak. the voice coil will eventually get too much hot at a point if no cooled and that will introduce taming and limitation in the spl, eventually break if the Xmech is reached. Also more distorsion when coming close to X-max.
For the very few I believe to have or not understood about horns : the impedance adaptation between the cone surface and the air of the room is more progressive and that helps the driver - such an input certainly a massive shortcut- But that's important cause for a driver the larger frequencies windows and the higher spl it has to reproduce in a short time, the more it will have coplex break-ups that give hard time to the reproduction fidelity : distorsion, micro spl dynamic mismatch - hence the love of ESL for micro details and acurate transcient-. The lower the cone surface the more difficult
For a sealed, that means a Qtc of 0.5 to have a transcient perfect speaker.
For vented, the group delay for some can not be heard, what is heard is the noise of the vents and perhaps the fact that this noise is lasting more than the orginal program. But I don't know...many sources don't argue the same. And DSP can solve that in digital FIR domain if one find it to be an important factor to him. However the vents and the room are certainly more the culprits to work on.
For a vented design many noticed a better subjective transcient and subjective hability when the box resonance is tunned above the driver resonance. Which is reducing the -f3. Trade off !
One can understand the importance of the amp & driver size in that purpose for the lowest frequencies to control the driver and to stop it without cone oscilations & break-ups -loaded energy- when playingback.
If the PA event is in a little venue, the room modes will hurt more than everything, the listening position is ruled by many bouncings, echos : playback reproduction is hurted cause the time delays of the notes are not comming at the same time. Rooms matter the most. Imagine a 20 eters wave length and you are at 10 meter of the speakers : you will have no problem of transcient if the speaker/amp can do it : most of the time it can. I.e. the first 10 meter of the 20 meter wave length will arrive for its main in the acurate time windows BUT you will hear he rest of the wave length : the last 10 meters after bouncings in the venues and a part of the first 10 meters after the direct radiation heard cause a part has met the floor, the walls, the chairs, the ceilling.
In the speaker choice, the T&S parameters help to make the work easier for bass : the lowest Le you can choose. The higher Qm you can choose, the lowest Qe you can choose -for vented design- and the higher Sd you can - 18" seems a limit when talking about acurate transcient. Then the mmd/qts ratio.
The Vas and the size of the speaker should NEVER be a problem : no trade off here.
To sumarize : sealed : the cone moves twice more than vented but it's easier to acheive transcient perfect alignment and the noise of the port not exesting you haven't a part of the signal that arrive after the main signal - room factor and placent is more important than with sealed designs- open bafle : the driver will move even more so will have to move faster which is producing more heat in the voice coil - and the size of the bafle hs to be huge to have not DSP -Linkwitz transform- in the low end when talking about bass. But each time the driver will move fast enough if it can and the amp can to reproduce the transcient needed.
I don't knoww if all is acurate here but that's how I understand it and hope that helps. If wrong inputs feel free to correct or ad precisions 🙂
What you say have some truth in it diyiggy. In general my thoughts are strong motor & light cone to achieve better transient response. Aside from esl speakers the real champions are well designed front loaded horn speakers whereby cone movements are so minute & with help of horn loading achieves far better transients then any other speakers that I've ever heard before. Having said that its has to be full horn set up including the bass cabinet.
"strong motor & light cone to achieve better transient response."
without stating the prime or lowest frequency how does one choose the appropriate stiffness?
and with horns doesn't compression ration come out to play?
without stating the prime or lowest frequency how does one choose the appropriate stiffness?
and with horns doesn't compression ration come out to play?
Im no expert when it comes to speakers Turk 182 but have always been intrigue by vintage horn speakers. The one thing that I noticed is the very thin cone material with very strong motor & stiff suspension & surround their x max is very small compared to todays drivers . Performance relies mostly to cabinet design & loading. Yes to do what they do set back is huge speakers but they just sound so effortless. Just think of the know the how they had back then example Altec A7 its just a 2 way speaker !!!!!!
Cheers
Cheers
ok i get it...never had the real deal to examine in real life...the three standard choices for the bass drivers in A7's we're not "lightweight" cones by any stretch off the imagination...but yes very efficient and strong motors.
Hi Turk 182 re Altec A7 woofers you must compare it to present day woofers then you'll see it more clearly.
A sealed speaker has only half the group delay of e vented one, even if the bass is boosted, because the vented takes the output of the backside of the diaphragm and delays it half a wavelength until it is in phase with the frontside.
The group delay is dependent on the fall off slope, sealed is 12dB/oct, and vented near 24dB/oct. (That is the same as the previous sentence, scientifically).
Additionally there is usually a steep subsonic filter needed for a vented speaker to avoid exessive excursion at lower frequencies like switching transients (like phantom power on) with another 24dB/oct.
So conclusion: a vented speaker has about 4 times the Group delay and the bass is limping behind.
The group delay is dependent on the fall off slope, sealed is 12dB/oct, and vented near 24dB/oct. (That is the same as the previous sentence, scientifically).
Additionally there is usually a steep subsonic filter needed for a vented speaker to avoid exessive excursion at lower frequencies like switching transients (like phantom power on) with another 24dB/oct.
So conclusion: a vented speaker has about 4 times the Group delay and the bass is limping behind.
Let's say that you cut off the part where the increase in group delay is in a ported speaker with an active crossover. Now, we essentially don't have that group delay cause it's on the lower end of the frequency scale. So, your playing around 150hz and above. How is the transients effected now?
I mean, is a sealed still more transient even though the longer group delay plays no role in the above frequencies?
Hi there,
I believe that it is a misnomer to talk about LF speakers having a 'transient response'. If they can reproduce the frequencies up to the point that they are crossed over then their transient capability (actually frequency response) is adequate. The fast rise times of any transient are handled by the HF driver - it would be prudent to remind oneself of the Fourier Transform of a square wave at this point. In short, subs provide the rough foundations of a transient event whilst the mid and particularly HF drivers define its leading edge.
'Step Response' is probably closer to the reality we are exploring here, and this depends to a huge extent upon the amount of stored energy within in a system, which is always largely resonant in nature. When looking at this aspect of the dreaded sealed vs. ported debate, then of course the ported enclosure is categorically worse, often more than an order of magnitude worse. I suspect this is where the awful descriptive term 'speed' has come about when talking about subwoofers. It is well-documented that group delay becomes increasingly inaudible as frequency decreases, however the resonant stored energy of ported and horn enclosures is considerably greater than sealed enclosures, and it appears to be this effect which is most objectionable. Let's not forget that a ported enclosure is a resonator - a mass/spring/damper system to use a mechanical analogy, and another comparison would be a racing car suspension (sealed) with a Cadillac's (ported) and their settling time following a bump in the road.
One of the acid tests is the double kick drum sound beloved of Metallica et al. Each impact is heard as a very well defined staccato, almost machine gun-like event on a properly designed (Qtc~0.5) sealed enclosure, whilst horn and particularly ported systems very often reproduce it as a drawn out and ill-defined phhhhtttttttt sound. The gaps between the sounds have been considerably blurred as the Helmholtz resonator is slowly expending its stored energy, which it has not done before the next sound arrives and repeats the cycle. I would never use anything but sealed enclosures when step response is critical - even my PA uses 6 x sealed 18" enclosures!
I believe that it is a misnomer to talk about LF speakers having a 'transient response'. If they can reproduce the frequencies up to the point that they are crossed over then their transient capability (actually frequency response) is adequate. The fast rise times of any transient are handled by the HF driver - it would be prudent to remind oneself of the Fourier Transform of a square wave at this point. In short, subs provide the rough foundations of a transient event whilst the mid and particularly HF drivers define its leading edge.
'Step Response' is probably closer to the reality we are exploring here, and this depends to a huge extent upon the amount of stored energy within in a system, which is always largely resonant in nature. When looking at this aspect of the dreaded sealed vs. ported debate, then of course the ported enclosure is categorically worse, often more than an order of magnitude worse. I suspect this is where the awful descriptive term 'speed' has come about when talking about subwoofers. It is well-documented that group delay becomes increasingly inaudible as frequency decreases, however the resonant stored energy of ported and horn enclosures is considerably greater than sealed enclosures, and it appears to be this effect which is most objectionable. Let's not forget that a ported enclosure is a resonator - a mass/spring/damper system to use a mechanical analogy, and another comparison would be a racing car suspension (sealed) with a Cadillac's (ported) and their settling time following a bump in the road.
One of the acid tests is the double kick drum sound beloved of Metallica et al. Each impact is heard as a very well defined staccato, almost machine gun-like event on a properly designed (Qtc~0.5) sealed enclosure, whilst horn and particularly ported systems very often reproduce it as a drawn out and ill-defined phhhhtttttttt sound. The gaps between the sounds have been considerably blurred as the Helmholtz resonator is slowly expending its stored energy, which it has not done before the next sound arrives and repeats the cycle. I would never use anything but sealed enclosures when step response is critical - even my PA uses 6 x sealed 18" enclosures!
All filters add group delay. In essence a box is also a filter, so it adds GD by its very existence.
My method of looking at group delay is that all the delay components need to be kept below the propagation time at any given frequency. A 30Hz wave has a propagation time of 1/30 = 33ms, so to keep "transient" response believable, the lumped GD at 30Hz needs to be 33ms or less, ideally half or less. This may not always be achievable, specially if a high-pass is also used. A few additional milliseconds at the bottom end is usually not an issue as room modes will generally add a lot more to the overall GD.
There is no such thing as a "Bass Transient" When you examine the nature of any transient, the reason you have an attacking sound is because of the balance in the ADSR of that transient. On almost all recorded material, the ADSR is engineered to produce what the musician or producer is going for, i.e. a sound effect.
There is no natural acoustic instrument that produces bass and has it stop on a dime. All large diaphragms tend to vibrate long after the original impact has died out. The complication is that all acoustic bass instruments tend to have a bunch of higher harmonics and the player has the freedom to excite those harmonics with something called 'technique'. That is what lends the perception of "slap" and punch" and "kick" that you get when these are played/recorded/played back.
Think about it this way - a drum with a fundamental frequency of 20Hz needs to be struck 20 times a second to only hear the first crest each time. I've no doubt that there is a drummer out there who can do that, but why would they?
To the subwoofer question, once you add the filtering needed to get a sealed enclosure to play the same level as a ported one, you will get roughly the same (if not worse) GD. My general experience is that ported enclosures do very poorly in rooms which are too small for them, and sealed subwoofers (excluding the 6x18 mentioned above) have a very tough time in large, cavernous spaces where they can sound empty and hollow. Each is a weapon, a tool, and you've to pick the right one for the job.
As to the double bass of Metallica on One, I hear it perfectly on ported systems I've done, no problem at all. Almost all commercial speakers tend to smear it so it's not the fact that it's ported, it's just poor design. Another track with those kind of transients is Allison Krauss "Simple Love", which is arguably tougher to reproduce because the sound really stands out due to the slow tempo of the song.
My method of looking at group delay is that all the delay components need to be kept below the propagation time at any given frequency. A 30Hz wave has a propagation time of 1/30 = 33ms, so to keep "transient" response believable, the lumped GD at 30Hz needs to be 33ms or less, ideally half or less. This may not always be achievable, specially if a high-pass is also used. A few additional milliseconds at the bottom end is usually not an issue as room modes will generally add a lot more to the overall GD.
There is no such thing as a "Bass Transient" When you examine the nature of any transient, the reason you have an attacking sound is because of the balance in the ADSR of that transient. On almost all recorded material, the ADSR is engineered to produce what the musician or producer is going for, i.e. a sound effect.
There is no natural acoustic instrument that produces bass and has it stop on a dime. All large diaphragms tend to vibrate long after the original impact has died out. The complication is that all acoustic bass instruments tend to have a bunch of higher harmonics and the player has the freedom to excite those harmonics with something called 'technique'. That is what lends the perception of "slap" and punch" and "kick" that you get when these are played/recorded/played back.
Think about it this way - a drum with a fundamental frequency of 20Hz needs to be struck 20 times a second to only hear the first crest each time. I've no doubt that there is a drummer out there who can do that, but why would they?
To the subwoofer question, once you add the filtering needed to get a sealed enclosure to play the same level as a ported one, you will get roughly the same (if not worse) GD. My general experience is that ported enclosures do very poorly in rooms which are too small for them, and sealed subwoofers (excluding the 6x18 mentioned above) have a very tough time in large, cavernous spaces where they can sound empty and hollow. Each is a weapon, a tool, and you've to pick the right one for the job.
As to the double bass of Metallica on One, I hear it perfectly on ported systems I've done, no problem at all. Almost all commercial speakers tend to smear it so it's not the fact that it's ported, it's just poor design. Another track with those kind of transients is Allison Krauss "Simple Love", which is arguably tougher to reproduce because the sound really stands out due to the slow tempo of the song.
The green curve is a closed box with the same 32Hz cut off las the vented (red). Both are crossed over at 125Hz with a 4th order Linkwitz-Riley Filter. The vented has additionally a 4th order high-pass at 28Hz
The delay is shown with the beige and blue curves.
We can also see the x-over causes 2ms of delay. For higher frequencies there is no difference between the two.
Here the pulse response is more significant, which is mainly determined by the cross-over.
So the group delay is important for the sub, a grand-piano player will not like a vented speaker which makes an "echo" or he will avoid playing the lowest octave
The delay is shown with the beige and blue curves.
We can also see the x-over causes 2ms of delay. For higher frequencies there is no difference between the two.
Here the pulse response is more significant, which is mainly determined by the cross-over.
So the group delay is important for the sub, a grand-piano player will not like a vented speaker which makes an "echo" or he will avoid playing the lowest octave
Attachments
The lowest octave on a piano consists of harmonics more than the string fundamentals, so I doubt that's an issue.
This statement is not true and doesn't represent real life situation.
First because sensibility to group delay vary with frequency: the lower the freq the less sensible we are to group delay, the conscensus about that atm is that there is threshold below which it is inaudible. Problem is there is no research ( afaik) published givin number to this.
Second because all this 'theorical' ideal low group delay only take one side of the coin in consideration: what happen to gd once sound produced propagate through a room?
To be more accurate what happen below Schroeder frequency and does it have an impact on gd?
If higher group delay introduced an echo you couldn't withstand bass reproduced in a room which obviously isn't the case.
There is testing which has been done, and graphs of sensitivity to group delay versus frequency have been published.