Subwoofer choice(PSA,SVS,HSU,JL Audio) for my 5.1 system

[shadyJ]

Here is a link to Jman's comparison of the SVS SB13U vs Rythmik E15HP:
http://www.avsforum.com/forum/113-subwoofers-bass-transducers/1471574-rythmik-e15-vs-svs-sb13-ultra-4.html#post24544440
I am inclined to believe Jman's observations between these two subs; he had both subs in his system at the same time for an A-B comparison. I have done similar comparisons and heard similar instances where one sub (in this case the SB13U) seemed not quite as accurate/tight in presentation of low end content.

It is possible that accurate deep frequency playback might sound laggy in the sense of a longer decay time due to the intrinsicly long waveforms of deep bass. When it comes to deep bass, 'seemed' is the key word here. You can't know until you have measured.

So, here is my question:

What would I look for in measurements to reveal this difference?

According to DataBass and all other accounts I have seen, the SB13U is certainly a tight sub. Of course the Rythmik E15HP is as well (but does not have DataBass measurements to compare).

I have seen arguments (and comments from the people making the measurements) that the slower time delay of some ported subs (which do not measure near so well as the SVS SB13U) is not audible.

There are obvious contradictions here. Can anyone provide a theory which is consistent with these findings? Where is the fault?

I will venture a couple theories. The differences that can be heard might just be slightly different distortion signatures, ie, slight more fourth order harmonic, slightly more second order harmonic. Some subs that are said to sound 'tight' might only have harmonic distortion which enhances upper bass frequencies, where human pitch definition is much better. IN a controlled enough setting, you may be able to hear these differences, even if they are not large. This article would be very pertinent here. Keep in mind group delay has not been comprehensively studied in bass frequencies, and most research focuses on 500 Hz and above in this area.

Also, the subs might simply roll off the deep bass, again putting emphasis on upper bass where we can discern detail much easier than at mid and especially deep frequencies.

 

[PENG]

The idea of comparing the waveforms of recordings is an interesting one. One way to do it for bass would be to shave off all the non bass content from the recording, leaving just the subwoofer band you wish to compare. Now compare that to the recording of a subwoofer's playback of that, and you might have something. Do a spectral analysis of both recordings to easily see the differences.

IF I recall correctly, Ed Mullen did do a bit of research into intermodulation distortion with Ilkka Rissanen, and this would be pertinent because intermodulation distortion is what occurs in more complex signals. What they found was that if a subwoofer has good control over harmonic distortion behavior, it will have lower intermodulation distortion. You can read about it in this audioholics article.

I was actually thinking of live recording a double bass solo, or an ensemble of double bass, and a few other instruments including tuba, bass drum etc. May be someone like Dennis Murphy (he plays in an archestra) and Ed Mullen can join force to get something done. Anyway, it's just a pipe dream..

 

[gankum]

Thank you everyone for your inputs/suggestions and time...

After further research & reviews, think I am going try the SVS PC13-Ultra...SVS SB13U & HSU VTF-15MK2 would have also met my requirements, I liked the flexible options(ported/sealed) with PC13-ultra & HSU, cylinderical design of PC13, low frequency response,power o/p and footprint&portability of the PC13. I had also looked into Adam's past reviews of his PC13Ultra and other reviews(for both movies & music).. + it "might" allow me to just go with a single sub with its huge o/p and I don't have multi-row HT setup. ( my ~1000 cubic ft HT section is closed on 3 sides(back continues into the larger room), side walls separated by only 12ft and the ceiling being only 8ft tall).

If it doesn't work out, I have the option of trying something else freely , with SVS and that by itself looked attractive to me. HSU still works out cheaper, even with warranty extension to 5 yrs + shipping etc, but somehow SVS seemed more flexible and more accessible customer service.

 

[PENG]

Thank you everyone for your inputs/suggestions and time...

After further research & reviews, think I am going try the SVS PC13-Ultra...

I am biased, so I think you made the right choice.

 

[shadyJ]

For a small footprint and solid deep bass output, it is hard to top the SVS cylinder subs.

 

[gankum]

I am biased, so I think you made the right choice.

I thought you might say it ..,when I came to know you own the monstrous SVS PB13-Ultra, yourself. Hope you are enjoying that!

 

[PENG]

I thought you might say it ..,when I came to know you own the monstrous SVS PB13-Ultra, yourself. Hope you are enjoying that!

I do own that, and a PC12U as well. Audyssey integrated them nicely.

 

[Steve81]

There are obvious contradictions here. Can anyone provide a theory which is consistent with these findings? Where is the fault?

Potentially. As you know, the room and the placement of a subwoofer(s) within it are key factors in what we hear at the MLP. Even seemingly minor variations in placement can produce significant effects in response. Even "identical" placement with subs having different dimensions can yield variances beyond what could be explained by just looking at data-bass graphs. Given this, if one were inclined to investigate the SQ differences between two subs in their room, I'd suggest starting with a battery of measurements at the MLP. The point here would be testing not just what the FR looks like at some low level, where room EQ would presumably flatten things out, but to see how the response changes as you dial up the SPL.