Subwoofer crossover, towers, bookshelves, and midbass slam.

[shadyJ]

I personally prefer 60hz xo because i think speakers cones, especially if they are small enough but capble of reproducing 50-60hz, returning back to initial position quicker than subs large drivers.

This is a misconception. Driver size does not mean that the moving mass will return to a rest position faster. That has nothing to do with the mechanics of drivers. Damping is the key here, not cone diameter.

 

[Andrein]

This is a misconception. Driver size does not mean that the moving mass will return to a rest position faster. That has nothing to do with the mechanics of drivers. Damping is the key here, not cone diameter.

But if your sub is ported like pb12 it will affect how quick is driver, no? This is the reason why some people pefers sealed subs for music.

 

[William Lemmerhirt]

But if your sub is ported like pb12 it will affect how quick is driver, no? This is the reason why some people pefers sealed subs for music.

Also not true. Having a better driver also means it has a motor structure/magnet/amp capable of better control. The “sealed is quicker/musical” thing is old news. Subwoofer drivers have come a long way, and IMO the only reason for a sealed sub is to save space/WAF. I suspect many people like a slightly lower XO is phase/time integration between subs and mains can be easier to accomplish. Also time relationship between the drivers in the speakers is bound to be better than with the sub and the speakers will carry more noticeable frequency range and sound cleaner and tighter.

 

[everettT]

Again, both you of guys are misreading those graphs. That is not a measure of transient response. Neither measurement is especially good or bad.

I wasn't stating the graph was referring to transient response. As for neither good or bad impulse response, I was under the impression that it was good, if not can you explain why as I might be missing something. Thanks.

 

[shadyJ]

The impulse response is a click that could only be perfectly reproduced by a loudspeaker that would have a perfectly flat response from DC to infinity Hz. In subs, it is largely a reflection of the frequency response of the unit. If you have a lingering measurement, that means the sub is bottom-heavy, ie its response is weighted more toward deep bass than upper bass. If it resolves quickly, it will have a response weighted more toward upper frequencies. It is really just another way of looking at frequency response if you felt like doing the mathematical transform. But since we hear frequency response and not impulse response, it isn't really relevant if you already have a frequency response measurement. It is much more useful as a tool to examine acoustics.

 

[Dale Doback]

This is a misconception. Driver size does not mean that the moving mass will return to a rest position faster. That has nothing to do with the mechanics of drivers. Damping is the key here, not cone diameter.

Try using your subwoofers as tweeters and come back and report.

 

[KEW]

Also not true. Having a better driver also means it has a motor structure/magnet/amp capable of better control. The “sealed is quicker/musical” thing is old news. Subwoofer drivers have come a long way, and IMO the only reason for a sealed sub is to save space/WAF.

Why don't measurements support that statement?
Why is the group delay so much superior when the SV PB13 Ultra is in sealed mode?
One would presume this driver was optimized for use in a ported sub, yet the group delay shows that sealing the cabinet improves performance substantially.
(Green=Sealed, Black=20Hz, Purple=15Hz)
Clearly, there is more to it than just size!

I will agree (and the measurements reflect) that a good ported sub (which I think we all can agree the pb13Ultra is) compares well and likely has little to no audible delay issues compared to sealed at the higher frequencies. I do believe that is an improvement over past ported drivers, but once you get into the tuning frequencies, a ported sub shows its hand.

 

[shadyJ]

Why don't measurements support that statement?
Why is the group delay so much superior when the SV PB13 Ultra is in sealed mode?
One would presume this driver was optimized for use in a ported sub, yet the group delay shows that sealing the cabinet improves performance substantially.
(Green=Sealed, Black=20Hz, Purple=15Hz)
Clearly, there is more to it than just size!

I will agree (and the measurements reflect) that a good ported sub (which I think we all can agree the pb13Ultra is) compares well and likely has little to no audible delay issues compared to sealed at the higher frequencies. I do believe that is an improvement over past ported drivers, but once you get into the tuning frequencies, a ported sub shows its hand.

Once you get into these tuning frequencies, delay issues become inaudible unless they are severe, so what difference does it make? I guess technically you could say the group delay measurements in sealed are superior, but in practicality it is pretty much the same. It's like arguing that 192kHz sampling rates are better than 96kHz sampling rates, well technically yes, but it doesn't matter to human hearing.

 

[yepimonfire]

But if your sub is ported like pb12 it will affect how quick is driver, no? This is the reason why some people pefers sealed subs for music.

Depends. A properly designed ported sub will have group delay, but as long as that delay is well below the subs useful frequency response it doesn’t matter.

My big 15” ported sub shows up as being very coherent and quick until well below the tuning. Same with my speakers.

I’ve heard good sealed subs and good ported subs. I’ve also heard bad ported subs. My speakers port tuning is 60hz, and 60hz sounds better coming from the speakers than the sub, even though 90% of that 60hz sound is coming out of the port rather than the driver. I think my situation is more placement/room interaction rather than fast vs slow subs.


Sent from my iPhone using Tapatalk

 

[yepimonfire]

Once you get into these tuning frequencies, delay issues become inaudible unless they are severe, so what difference does it make? I guess technically you could say the group delay measurements in sealed are superior, but in practicality it is pretty much the same. It's like arguing that 192kHz sampling rates are better than 96kHz sampling rates, well technically yes, but it doesn't matter to human hearing.

There’s actually some evidence from about 3-4 studies showing that ultrasonic frequencies, while inaudible as pure sine waves, do alter the perception of music, and are usually picked as preferred. Same with infrasonics. Obviously, at a loud enough volume, humans can hear down to 8hz, but this is on the order of 100dB+. Several studies have shown that even at lower levels infrasonics added to music will invoke fear or awe.

I think the jury is still out on the benefits, or lack thereof, of high res music. I do know I was able to abx Coldplay’s Clocks 24/96 version vs the 16/44 version in foobar.


Sent from my iPhone using Tapatalk

 

[William Lemmerhirt]

Why don't measurements support that statement?
Why is the group delay so much superior when the SV PB13 Ultra is in sealed mode?
One would presume this driver was optimized for use in a ported sub, yet the group delay shows that sealing the cabinet improves performance substantially.
(Green=Sealed, Black=20Hz, Purple=15Hz)
Clearly, there is more to it than just size!

I will agree (and the measurements reflect) that a good ported sub (which I think we all can agree the pb13Ultra is) compares well and likely has little to no audible delay issues compared to sealed at the higher frequencies. I do believe that is an improvement over past ported drivers, but once you get into the tuning frequencies, a ported sub shows its hand.

Not sure how I missed this one Kurt. I have to say I feel the graph only shows “measured” superiority. Not sure you could tell. In any case, I’m not experienced enough in taking group delay measurements to be great at interpreting these. I’m happy to have you enlighten me, but to my novice eye, it looks like these are pretty normalized by about 27hz which also makes me think for music, you’d never know since the GD effect is mostly below music range. Also, fwiw I’ve read quite a few reports by owners of the pb13u that they did not enjoy it for music. Seems SVS might have slanted it towards HT just a smidge.(maybe). I wonder (just for example) if you’d be able to tell the difference with music between a properly integrated fv15hp, and an f15hp, or an sb2k and a pb2k, or any other pair of competently designed ported/sealed competitors. Obviously the ported subs would “show their hand” with movies.

 

[Steve81]

Why don't measurements support that statement?
Why is the group delay so much superior when the SV PB13 Ultra is in sealed mode?

FWIW, part of it has to do with the fact that SVS utilizes a HPF to offer protection to the driver against frequencies below port tune. This results in a very sharp roll off in FR and a spike in GD. To see that in action, you can compare one of Josh's DIY vented builds with a HPF (black) and without (green):

 

[Steve81]

For folks that believe that a larger driver just can't function well in the time domain at 60Hz+ vs smaller drivers, here's a waterfall comparison to think about:

That's a 21" driver vs an array of 10s.

 

[Steve81]

I could not disagree more. It is not just a matter of spl.

Quality/coherence isn't just a matter of SPL, but achieving the physical sensation of "midbass slam" is almost entirely a matter of output at the seats IME.

To put it another way, a perfectly time aligned system playing at low "background music" levels simply isn't going to deliver "slam". OTOH, even if you throw the timing of my subs off by 100ms, if they're cranked to 11, slam there will be, even if overall the setup sounds poor as a result.

 

[KEW]

I’m happy to have you enlighten me, but to my novice eye, it looks like these are pretty normalized by about 27hz which also makes me think for music, you’d never know since the GD effect is mostly below music range.

I guess that depends on whether the recording engineer uses some type of filter on the low end. Every now and then I come across music which makes me want to disable my subs because of some low frequency content that was not intended to be part of the recording. This is a liability of mixing on gear that does not reproduce the lowest audible frequencies.
In the case of the PB13Ultra, Ricci states

In 20Hz mode the PB13-Ultra offers the most output and least amount of compression compared to the other 2 modes of operation. The Ultra offers useful response up to almost 200Hz in all modes. The output compression and overall output headroom in 20Hz mode is slightly better than the other 2 modes of operation partly due to the increased port area and sensitivity above 20Hz. Sealed mode generally has the lowest maximum output and higher distortion. The distortion performance is exemplary above 20Hz regardless of configuration and the PB13-Ultra shows very good bandwidth uniformity between 20-125Hz at maximum output levels. There is the usual increase in group delay exhibited by a vented subwoofer with a steep high pass filter but otherwise the energy decay looks very good as well. In sealed mode the PB13-Ultra offers the best signal decay. 20Hz configuration offers the most headroom, 15Hz is likely to be the best operation mode for most users.

So, despite the 20Hz tune offering more headroom, he believes the 15Hz tune will likely be preferred by most users, but he does not state specifically why. My guess is because the group delay issues are pushed down below audible frequencies while headroom is still good for the 15Hz tune:

@shadyJ , what other reason to prefer the 15Hz tune over the 20Hz tune?

 

[shadyJ]

I guess that depends on whether the recording engineer uses some type of filter on the low end. Every now and then I come across music which makes me want to disable my subs because of some low frequency content that was not intended to be part of the recording. This is a liability of mixing on gear that does not reproduce the lowest audible frequencies.
In the case of the PB13Ultra, Ricci states



So, despite the 20Hz tune offering more headroom, he believes the 15Hz tune will likely be preferred by most users, but he does not state specifically why. My guess is because the group delay issues are pushed down below audible frequencies while headroom is still good for the 15Hz tune:

@shadyJ , what other reason to prefer the 15Hz tune over the 20Hz tune?

I doubt he says to go with 15 Hz tuning over 20 Hz tuning because of group delay. Neither would be audible. I am sure he says to go with the 15 Hz tuning because it gives up very little output against the 20 Hz tuning for significantly deeper extension.

 

[rolf.taylor]

I could not disagree more. It is not just a matter of spl.

A drum crack is complex, there is the strike with a lot of HF content the bang and decay.

Timing of all this is crucial.

I have an instructor at a college. He has Genelec speakers in his studio. He vows my speakers are the only ones he has heard that reproduce drums realistically.

You mentioned this guy before. Have you taken your speakers over to his studio? If not your claim that his speakers don't sound as good as his is just that, a claim! As everyone on this forum should be aware, the room is an extension of the speakers.

Another point, is the purpose. Many speakers serve to "pretty up" mediocre mixes. Studio monitors (like most Genelecs) are supposed to be neutral, and as such, may sound on the poor side with mediocre material.

 

[TLS Guy]

You mentioned this guy before. Have you taken your speakers over to his studio? If not your claim that his speakers don't sound as good as his is just that, a claim! As everyone on this forum should be aware, the room is an extension of the speakers.

Another point, is the purpose. Many speakers serve to "pretty up" mediocre mixes. Studio monitors (like most Genelecs) are supposed to be neutral, and as such, may sound on the poor side with mediocre material.

The mains weigh 350 lb each and the center is through wall.

The recording was this one.

That is widely regarded as one of the finest recordings of drumming around.

 

[SVSDual]

Also not true. Having a better driver also means it has a motor structure/magnet/amp capable of better control. The “sealed is quicker/musical” thing is old news. Subwoofer drivers have come a long way, and IMO the only reason for a sealed sub is to save space/WAF. I suspect many people like a slightly lower XO is phase/time integration between subs and mains can be easier to accomplish. Also time relationship between the drivers in the speakers is bound to be better than with the sub and the speakers will carry more noticeable frequency range and sound cleaner and tighter.

From my own personal experience, all of this is true.

I'm a heavy music listener and overly picky about the sound and accuracy of what I'm listening to lol. I've spent a little over a year with a sealed sub and recently switched over to ported. I much prefer the overall sound and accuracy of the ported sub.

 

[NINaudio]

From my own personal experience, all of this is true.

I'm a heavy music listener and overly picky about the sound and accuracy of what I'm listening to lol. I've spent a little over a year with a sealed sub and recently switched over to ported. I much prefer the overall sound and accuracy of the ported sub.

Which two subs are we talking about here?