İs my subwoofer faulty?

[lovinthehd]

Some discussion of group delay for sub frequencies here

 

[Verdinut]

Here are a few older discussions on group delay:

https://www.audioholics.com/loudspeaker-design/sealed-vs-ported/sealed-vs-ported-p2

IMO, a vented enclosure using a woofer or a subwoofer with appropriate Qts, with a proper tuning alignment will exhibit a low group delay and excellent transient response below and above 100 Hz. On the other hand, if a driver with a Qts higher than 0.45 is used in a badly tuned box and driven with an amplifier that has a high output impedance, then you can expect a long group delay and poor transient response.

 

[KEW]

From Audioholics article, 2015:

According to the respected audio researcher Peter Mitchell, group delay in excess of 20 milliseconds can alter the subjective character of bass in more commonly heard bass frequencies, so for 50 Hz and above group delay should be kept to less than a single cycle for total inaudibility.

https://www.audioholics.com/loudspeaker-design/audibility-of-distortion-at-bass

I think 1.5 cycles is often used as an objective at lower frequencies, but I am not sure if that has a legitimate basis.

 

[William Lemmerhirt]

I don't know that I've ever said that regarding group delay.
However, if you are saying Group delay could never be audible, I would be looking for a more thorough explanation.
The statement that "Group delay could be audible" seems pretty sound to me!

Huh...
Well Kurt maybe my memory is slippin. I surely thought we covered it in a thread with shady before. In any case, I’m not saying group delay can NOT be audible. My thoughts though, align with what @Verdinut was saying. A low Q well designed and built subwoofer should exhibit low enough group delay as to not be audible during almost all music playback. Movie playback, which I am also a big fan of had much more potential for group delay to be audible, but probably not relevant. Who knows, maybe I have group delay.....

 

[lovinthehd]

I don't know if I have group delay, but there's certainly some delay at my age....

 

[William Lemmerhirt]

I don't know if I have group delay, but there's certainly some delay at my age....

Yeah good point. I’m ON delay. I cause my group TO delay....

 

[lovinthehd]

Yeah good point. I’m ON delay. I cause my group TO delay....

Yeah I've got most of the delay on group rides these days

 

[William Lemmerhirt]

Yeah I've got most of the delay on group rides these days

Lol. I hear that too. Not as a fast as I used to be. Oh wait, is that a caliper hanging up...yeah that’s it.

 

[KEW]

Huh...
Well Kurt maybe my memory is slippin. I surely thought we covered it in a thread with shady before. In any case, I’m not saying group delay can NOT be audible. My thoughts though, align with what @Verdinut was saying. A low Q well designed and built subwoofer should exhibit low enough group delay as to not be audible during almost all music playback. Movie playback, which I am also a big fan of had much more potential for group delay to be audible, but probably not relevant. Who knows, maybe I have group delay.....

Well it said that sealed have less group delay that ported subs, if that is indeed true, the sealed sub would be preferred over ported. I don't know if that claim has been substantiated through objective testing. There is a gentlemen here with Audioholics that claim " group delay" could be audible. Tight bass is considered "musical" bass without a lot of over hang.

Well, I don't really have reason to dispute anything in the bolded text (aside from the "gentleman" part). However, I don't usually use the term "group delay", as I usually think of it in terms of bloated bass or too much overhang. Likely, in the middle of a conversation, if GD were the term being bandied about, I would probably conform to using it, but I don't understand what the "group" being delayed is so am not too quick to use it!
In accord with Auditor55's statement, I certainly would claim that delay or overhang can be audible, and I would agree that tight bass without overhang is much more musical than the alternative.
But Auditor55 is the one who would know who he is referring to - or he may remember content more than author. In actuality, although he may not have been the originator, I don't think ShadyJ would dispute anything in those two statements. He may want to qualify them, but I believe very few would argue those, as worded, as being outright false statements.

 

[Verdinut]

If the sealed box gives the shortest group delay figure but we know that it will show more distortion than what you get with a vented one, I would prefer the lower distortion level of the bass reflex because distortion is more easily detected than a slightly longer group delay.
All the high end tower speakers and commercial subwoofers use vented cabinets. If the group delay was that bad, the vented design would have been abandoned with time.
As I mentioned in a previous post, the overall performance of a vented speaker depends on the design, and with a truly well tuned and sized box using a driver with a Qts between 0.20 and 0.45, the group delay shouldn't be a concern.

 

[lovinthehd]

If the sealed box gives the shortest group delay figure but we know that it will show more distortion than what you get with a vented one, I would prefer the lower distortion level of the bass reflex because distortion is more easily detected than a slightly longer group delay.
All the high end tower speakers and commercial subwoofers use vented cabinets. If the group delay was that bad, the vented design would have been abandoned with time.
As I mentioned in a previous post, the overall performance of a vented speaker depends on the design, and with a truly well tuned and sized box using a driver with a Qts between 0.20 and 0.45, the group delay shouldn't be a concern.

I wouldn't say all the high end subs are ported....many are still sealed. For very low bass distortion detection is hard, too.

 

[Verdinut]

I wouldn't say all the high end subs are ported....many are still sealed. For very low bass distortion detection is hard, too.

As mentioned previously by ShadyJ and others, all sealed subs produce more distortion because they don't have much headroom because the air is trapped within the box. You have the compression and decompression effect which causes non-linear cone movement.

 

[lovinthehd]

As mentioned previously by ShadyJ and others, all sealed subs produce a lot distortion because they don't have much headroom because the air is trapped within the box. You have the compression and decompression effect which causes non-linear cone movement.

There are some with reasonable distortion spec in a range that again is hard to detect. YMMV. With enough of them it doesn't matter much, either.

 

[Verdinut]

I wouldn't say all the high end subs are ported....many are still sealed. For very low bass distortion detection is hard, too.

As stated by loudspeaker experts, a sealed box is a compromise unless the driver uses an acoustic suspension. I doubt that any of today's high end subwoofers uses that design so they also represent a compromise for space saving. If you have the room space, the well designed vented box is the way to go for increased efficiency, lower distortion and more headroom.

 

[lovinthehd]

As stated by loudspeaker experts, a sealed box is a compromise unless the driver uses an acoustic suspension. I doubt that any of today's high end subwoofers uses that design so they also represent a compromise for space saving. If you have the room space, the well designed vented box is the way to go for increased efficiency, lower distortion and more headroom.

Funk, JTR, Seaton, JL, Deep Sea Sound, Rythmik etc. all offer high end sealed subs.

 

[Verdinut]

Funk, JTR, Seaton, JL, Deep Sea Sounds, Rythmik etc. all offer high end sealed subs.

And their vented subs, if they manufacture them, perform better than their sealed ones, that's a fact.

 

[KEW]

And their vented subs, if they manufacture them, perform better than their sealed ones, that's a fact.

And yet, strangely, Gene (Velodyne DD15+'s in the Audioholics Showcase System, JL Audio e112's in the AH family room showcase, and Velodyne mini-vee for his PC system),Steve81 (Funk 21" sealed),and Jman (JTR S1) all use sealed subwoofers!
Go figure!

I'm not arguing that sealed are better, I am just pointing out that it is not such a "no-brainer" as you present it!

 

[lovinthehd]

And their vented subs, if they manufacture them, perform better than their sealed ones, that's a fact.

In some respects. There's still compromise involved on vented designs, too. Don't believe JL or Deep Sea offers a vented design, tho.

 

[killbill13]

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[KEW]

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