I have a similar experience to what ICG is saying here, if the sound is very clean and precise people are not used to it, some of them will push the gain of certain frequencies. Personally I think it works better to go for the classic JBL tilt.
A lot of music is mastered with a strange focus centered on the midrange, as I have the understanding that even many of the studio producers do not have good quality in the lower frequencies on their own sound systems. Even with all the difficulties getting high frequency performance right because of diffraction and reflective surfaces and objects, the higher frequencies are significantly easier to get right than the lower bass region, so the vast majority is simply blissfully unaware. This is true for filtering as well, it is significantly easier to solve mid and higher phase issues with FIR and simply leave the bass as a muddled mess and not deal with it properly.
Lack of understanding + lack of means + lack of good finished solutions that can be bought ready off the shelf.
Apologies for the slight rant.
A lot of music is mastered with a strange focus centered on the midrange, as I have the understanding that even many of the studio producers do not have good quality in the lower frequencies on their own sound systems. Even with all the difficulties getting high frequency performance right because of diffraction and reflective surfaces and objects, the higher frequencies are significantly easier to get right than the lower bass region, so the vast majority is simply blissfully unaware. This is true for filtering as well, it is significantly easier to solve mid and higher phase issues with FIR and simply leave the bass as a muddled mess and not deal with it properly.
Lack of understanding + lack of means + lack of good finished solutions that can be bought ready off the shelf.
Apologies for the slight rant.
That may be true but the question is that the bloated sound is caused by high group delay or something else.
High group delay (GD) is a big part in this, so is distortion profile. I would say that if you look at it from an isolated perspective then GD is a symptom that points to a problem rather than the specific cause. A bit like if your Doctor is giving you medicine to deal with a symptom rather than looking into what the cause of the symptom can be.
I have seen the same thing that you are talking about, low Q causing higher GD, yes it is a thing, a good solution is to push the response lower to a place where it is less if an issue, often this will cause you to choose different drivers.
I have seen the same thing that you are talking about, low Q causing higher GD, yes it is a thing, a good solution is to push the response lower to a place where it is less if an issue, often this will cause you to choose different drivers.
The symptom is the bloated sound. Is this caused by the high group delay or not?
Did anyone heard the sound of
the Neumann KH420 as bloated? It have a high group delay in the sub-bass range (about 30 Hz) caused by low Q driver in a vented box. A similar alignment as the thread title is about.
Okay, some says it is better to push the group delay lower in the frequency range by tune the Fb lower. This typically results in a cleaner sound. But the cleaner sound is caused by the lowered frequency of the GD peak or more damping of the driver itself where the Fb got placed (the lower the frequency, the higher the damping of a dynamic driver is, moreover a low Q also means high damping).
Time and again, group delay has nothing to do with Q or box type. Group delay follows directly and only from magnitude frequency response and nothing else, period. It does not matter how that frequency response was achieved.
A speaker like KH420 ususally has a 5th or 6th-order roll-off, 4th order from the ported alignment and another one or two orders from a subsonic filter.
It does IMO. To get the same response as the KH420 have, a high Q (caused by low Bl) driver needs a ton of EQ boost in the low range. Do you think it would results in the same sound as the KH420 have? Why they choosed a high Bl, low Q (also means more expensive) driver in the first place if a higher Q driver would be sufficient?
Perhaps it was not clear enough in my previous reply, I was talking about drivers in specific enclosures.
KSTR is also correct in what he is saying, that GD is a function of the response, however, very low q drivers behave differently near FS than higher q drivers (duh, of course! Some might say). It is easier to push a 0.35-0.45 driver lower than FS, whereas a 0.2 driver FS is in some cases the absolute limit, and if you try to make it do something it is not optimalized for then you end up with a significantly worse result than if you chose a cheaper unit.
It is easier in what ways? Easier because a higher Q driver have lower damping, causing a more bloated sound in general than a lower Q driver.
In an adequate alignment (EBS instead of QB3 for example) a low Q driver can be pushed below Fs but it needs a cut upper in the frequency range to get flat frequency response.
This results in a high group delay down low but is seems this is not a problem (see KH420 for example).
You are mixing that up. A low Qes driver (strong "overdamped") needs boost, whereas a high Qes (weak "underdamped") typically needs a cut.
For a ported design, one of course needs a driver with just the proper amount of damping to make the Helmholtz resonator work properly. Too low Q gives too narrow bandwith (too high Q) of the port, too high Q makes bandwith too wide and losses too large.
What means "working properly"?
Why Neumann (or Genelec) chooses low Q (lower than "optimal") drivers in their designs?
How do you even know what Q their drivers have? They did not disclose the specs. The KH420 uses a custom version of a 12" PHL.
Speaker design is about making the right compromises. It turns out you get better results overall when using a Q on the lower end of the tolerable design space, for a number of reasons.
It's 10". Its Fs probably lowered from the upper 40s but it's still a low Q driver IMO.
That's wrong. Take any driver and cross it over at 48dB and then look what the GD does.
You mean the protection high-pass of the subwoofer?
Edit:
Anyway, this is not a problem of low Q drivers in a vented box but the excessive filtering that was applied.
It probably would resulted in similar bloated sound if the subwoofer would have been a low GD sealed design.
Last edited:
For example, or reduce the frequency response peak around Fb with adequate filtering or applying digital phase linearization filtering, just to name a few.
But anyway, the "slight" peak in group delay caused by low Q driver in a vented box doesn't seems to be a problem. As we can see above, what ICG had to deal with was the excessive filtering, not the subwoofer (and its own group delay) itself. A typical low Q driver in a normal or even in a larger vented box never causes so much GD than a 48 dB/octave high-pass filter does.
Last edited:
The end result is a sum of many variables, like mentioned by several previously here it is possible to simplify the answer to: response dictates group delay (even though that is part of the end result and not the cause).
It is all a compromise of design, and design goals, then you have implementation as well as other potential influences in the system like filters, eq, matching+++.