Too Much Sub?

[Nuance AH]

I can pee farther than all of you, so there....

I can't compete with that - you win! LOL!

 

[DS-21]

The 2K's,

Good drivers, and well-implemented system. I suspect you won't notice much if any real improvement from the Ultras, though often for most of us (myself certainly included) "having the best" is its own reward.

I'd still take the 5400U, as they are more bullet proof. A buddy of mine wrecked three 18" Mal-X's.

Incorrect.

The LMS-Ultras is not bulletproof at all, because they're not a "bottomless" design: it by design has more motor than suspension, so the motor can send the coil former crashing into hard metal plates with alarming amounts of force. So, enough power and a very LF signal at high SPL...time for a new top assembly. One can reasonably argue whether that's a bug or a feature of the design, but the fact that they can be bottomed is a fact of life.

As for the Mael-X, there were several generations of the driver.
The last generation (3d or 4th gen of the 18, I think all of the 21's but could be wrong on that) had production problems with the epoxy on the shorting rings coming loose, yes. (Unfortunately, those buildhouse problems sunk Exodus Audio.) The earlier ones are quite durable, though. I don't think I've yet read a report of an earlier Mael-X failing, though I'm sure a few have. FWIW, mine is a Mk. I, dating back from Mr. Haskin's first preorder run ca. 2007. The Mk. I had dual 8Ω voicecoils, I think a little less throw than later ones (still 30ish mm), and by far the lowest normalized inductance (.87mH Lep/3.1Ω Rep) of the line. Later ones had different vc configurations, and markedly higher inductance.

The same applies to the FV15HP.

No, it doesn't. They have poor upper bass extension, and their crossover controls are mislabeled.

You're putting an awful lot of effort into white-washing those two readily-apparent facts.

I'm beginning to see where your allegiance lies,

Where, exactly? Peerless?

I don't believe in brand loyalty in anything, really. Loyalty to first principles, yes. To corporate entities? No. Not even ones with the pedigree and track record of Aurasound, KEF, or Tannoy.

Even though the XLS and XXLS lines (as well as their step-drivers born from the Tymphany/ScanSpeak divorce, the 10" and 12" ScanSpeak Discovery 4558T) have been around for over a decade, they are still reference-class subwoofer drivers. Good top-end extension, decent throw, conventional but very well-optimised motor and suspension design, excellent build quality and unit-unit consistency. (Those last two things, one has to note, have never been TC Sounds' forte...)

By selecting the fantastic XXLS12 for their entry-level product, SVS basically ensured that they would have a winner on their hands with their 12" subs. I'm still shocked at how low they're priced.

Remember, Genelec's sub using four XLS12's won Keith Yates' old "Way Down Deep" comparison.

Given their price and performance, the PB12 NSB and SB12 also frankly make SVS's more expensive products less attractive.

That said, any person of good faith and reasonable intelligence reading this thread will see that my "allegiance" is simply to high-fidelity reproduction, with a premium on the getting smooth upper bass in room, because music generally has more information there. Someone less interested in reproducing music with high fidelity, and more interested getting maximum excitement from explosions and such from Hollywood's in plotless special effects spectaculars probably should have different "allegiances" from mine.

Not at all, but what does that have to do with the FV15HP?

Brian Ding's flakey comments about wire "sound" (for subwoofers, no less!) are indicative of his generally misplaced priorities.

Another example of such misplaced priorities are his servo design that gives up something valuable (top-end bandwidth) for something of debatable at best merit (lower 2d order distortion down low).

Actually no, and I never said I did. Have you looked at the max output charts yet? I really don't think the FV15HP will have any rolloff up to 125Hz in a typical listening environment.

You need to learn the difference between "frequency response" and "max output." It's not a hard distinction to grasp.

 

[DS-21]

A sub that gets 105+ below 20hz is not a bad sub.

All getting 105+ dB ground plane below 20Hz means is that a sub is a pretty good ULF pump. That does not say it is a good sub, because it says nothing about its ability to play cleanly all the way through the modal region.

I think you're reacting to something that was not written or implied, though. I never called the LMS-Ultra a bad sub, or anything like that. I said merely that on program material I enjoy I could not perceive a difference between it and another very, very good driver. That makes the LMS Ultra, at the very worst, a very, very good driver.

TC has had their issues with insolvency,

And unit-unit consistency.

And build quality.

And packaging (example: for a time, at least, they would just throw the washers for their VMP passive radiators into the shipping box. Obvious and eminently foreseeable result? Dented cones.)

But when they're on their game, I agree that TC's introduced some standout woofers (his original underhung stuff that turned into Audiomass that turned into SVS Ultra, TC2+/TC1000/Epic, TC2k, LMS, a few of the LMT-motored Eclipse-branded drivers) as well as some real dogs (HE15, anything with the 3HP or 4HP motor, TC3k).

 

[Nuance AH]

That makes the LMS Ultra, at the very worst, a very, very good driver.

Because you couldn't hear a difference and you say so? We all know the LMS is a great driver and don't need your blessing. You're generally a smart guy and you know your stuff, but you and your self-appointed know-it-all tone... Have you ever heard of the word "humility?"

\
You need to learn the difference between "frequency response" and "max output." It's not a hard distinction to grasp.

I know the difference. Read my entire statement in which I said its unlikely the subwoofer would roll off below 125Hz in a typical listening room (obviously when crossed to the mains); I'm speaking directly about frequency response. The max output simply shows it isn't limited at the upper frequencies.

Like I said, this is a waste of time. We'll agree to disagree, even though we pretty much agree. HA!

 

[timoteo]

Move along folks! Nothin to see here!...

Everything has been handled & nobody got hurt!!!

Some crazy weather we've been havin eh?

 

[DS-21]

Because you couldn't hear a difference and you say so?:roll eyes:

In case you didn't notice, those words were a rebuttal to a comment by someone-who-was-not-you that I believe implied I called it a bad driver when I in fact did not. I wrote to clarify that I did not call it a bad driver.

That said, have you ever organized or participated in a blind test of subs? I've done three.

I'm planning a fourth, which will compare a multisub systems composed of elite-level drivers (Aurasound NS) in closed boxes, to a multisub system composed of merely excellent drivers (Peerless 830500, "XLS-12") in distortion-reducing and efficiency-enhancing 4th order bandpass enclosures.

We all know the LMS is a great driver and don't need your blessing.

We also know from reading various audio fora that new LMS Ultras routinely ship with build quality defects that simply should not happen on a $200 driver let alone nine hundred plus dollar one.

For example, poor machining of the threads in the motor (which must be assembled by the end-user, remember, unlike the Aurasound NS18 and even the RE XXX 18) is widely reported. (Fortunately, when I bought mine, they were still shipped in one piece, so such flaws were not left to an end user excited by her/his new $925 toy to discover.)

I hate to say it, because TC have some great ideas, but from what I've personally seen from them and read from others' experiences, I get the feeling that a way-too-high percentage of the stuff TC Sounds ships to customers factories would be laughed out of QC from an Aurasound, B&C, or Peerless.

At the prices they charge, I believe they should not only be on the cutting edge of technology, but also built to a very high standard.

Read my entire statement***

I read your entire statement, and with my rebuttal statement above dismissed it as simply and obviously wrong.

 

[TLS Guy]

Hey DS-21, I have a question. Lets say for the sake of argument that Rythmik's top end roll off is unsatisfactory for the perfect system. What about all the systems where people just have one sub, and its crossed over at 80 hz in a normal room, you know, less than perfect. Do you think Rythmik would be a poor choice then?

Remember if you set a crossover to 80 Hz the driver should only be 3db down at 80 Hz. So even with a fourth order crossover (typical), the driver will not be below -24 db until 160 Hz. So for an 80 Hz crossover you really should have a bandwidth out to 160 Hz and to 200 Hz for a 100 Hz crossover.

 

[TLS Guy]

DS-21

Here we might part company a little bit. A few years ago I did a blind test with a sub EQ'ed to as close-as-possible-with an SMS-1 response, using a JBL W15GTi (a very, very good woofer with JBL's Differential Drive motor, good to about 700Hz, incidentally), and couldn't tell a difference with measured Qtc ranging from about .56 to almost 1. And even then, I don't know if it was the efficiency loss or the Q that made the smaller box audibly different.

The bottom line with Q is that IMO so long as one can equalize to the desired response curve, it's not a huge issue. If one doesn't have a good parametric sub EQ, IMO always err on the side of as low a Q as possible.

Actually the placement of Qtc is one of the biggest factors that sets the quality of the bass of speaker systems apart. I can tell after a short audition the general area of the Qt of the bass loading of a speaker.

High Qt subs spread a goopy ooze all over the sound field. In my view they are in no way accurate.

 

[DS-21]

Actually the placement of Qtc is one of the biggest factors that sets the quality of the bass of speaker systems apart. I can tell after a short audition the general area of the Qt of the bass loading of a speaker.

I assume you're talking about unequalized systems here. In that case, I agree.

In my comparisons with the JBL W15GTi in different sized cabinets, note they were all equalized. (Some might say "Linkwitz transformed," but it's all just equalization to the same basic response shape.)

I came away strongly feeling that subjective bass quality is overwhelmingly determined by the subs' in-room frequency response. So my current approach for a closed box sub is to size the cabinet such that the amplifier I'm using can push the driver to its rated xmax, and not really worry about Q.

Mind, before actually experimenting with the same driver in boxes of different sizes (and thus different Q's) equalized to the same response, I would've insisted that if it's above .577 or so, it's no good.
(And to be sure, before EQ I did think that the big, low-Q box was much better sounding.)

Though I suppose one could argue that the W15GTi* is such a good driver - with its very smooth and progressive BL and compliance falloff over stroke, bottomless-through-magnetic-braking split opposed voicecoils, and greater heat-sinking area than many amplifiers - that it's not representative of the drivers many people use because it has so much less thermal compression than typical drivers. But that would mean that what people are attributing to high-Q is really thermal compression...

*while marketed as a "car" driver, it's really the JBL Pro 2256G driver from some subs in their flagship Vertec line, but sadly fitted with a gaudier dustcap.

 

[TLS Guy]

I assume you're talking about unequalized systems here. In that case, I agree.

In my comparisons with the JBL W15GTi in different sized cabinets, note they were all equalized. (Some might say "Linkwitz transformed," but it's all just equalization to the same basic response shape.)

I came away strongly feeling that subjective bass quality is overwhelmingly determined by the subs' in-room frequency response. So my current approach for a closed box sub is to size the cabinet such that the amplifier I'm using can push the driver to its rated xmax, and not really worry about Q.

Mind, before actually experimenting with the same driver in boxes of different sizes (and thus different Q's) equalized to the same response, I would've insisted that if it's above .577 or so, it's no good.
(And to be sure, before EQ I did think that the big, low-Q box was much better sounding.)

Though I suppose one could argue that the W15GTi* is such a good driver - with its very smooth and progressive BL and compliance falloff over stroke, bottomless-through-magnetic-braking split opposed voicecoils, and greater heat-sinking area than many amplifiers - that it's not representative of the drivers many people use because it has so much less thermal compression than typical drivers. But that would mean that what people are attributing to high-Q is really thermal compression...

*while marketed as a "car" driver, it's really the JBL Pro 2256G driver from some subs in their flagship Vertec line, but sadly fitted with a gaudier dustcap.

Q does not have anything to do with frequency response per se, but damping essentially. High Q systems have sustain, which is the problem and excites room modes excessively. They bloom and I can't stand them, and they are not accurate period.

 

[DS-21]

Q does not have anything to do with frequency response per se, but damping essentially.

No.

If one modifies the FR, one changes the damping and in fact the damping (Q) of the system!

The common term for that is "Linkwitz Transform."

See http://www.linkwitzlab.com/thor-eq.htm, Linkwitz Transform Subwoofer Equaliser

From your response I can only assume you've not compared systems of varying native Q equalized to match FR. It's one of those eye-opening things that challenges a lot of reasonable-seeming intuitions.

 

[TLS Guy]

No.

If one modifies the FR, one changes the damping and in fact the damping (Q) of the system!

The common term for that is "Linkwitz Transform."

See Subwoofer equalization, Linkwitz Transform Subwoofer Equaliser

From your response I can only assume you've not compared systems of varying native Q equalized to match FR. It's one of those eye-opening things that challenges a lot of reasonable-seeming intuitions.

That works for sealed but not other alignments. If you don't choose a sloppy high Qts driver then a sealed enclosure will usually have a Qt on the lower end of the scale anyway.

 

[Nuance AH]

That said, have you ever organized or participated in a blind test of subs? I've done three.

I'm planning a fourth, which will compare a multisub systems composed of elite-level drivers (Aurasound NS) in closed boxes, to a multisub system composed of merely excellent drivers (Peerless 830500, "XLS-12") in distortion-reducing and efficiency-enhancing 4th order bandpass enclosures.

This is what I heard going through my head as I read your quote. I just couldn't help myself.

I've not participated in blind sub tests, only blind speaker tests. I've partaken in sighted subwoofer tests and GTG's, though, most notably this one (of which Ricci attended):
http://www.avsforum.com/avs-vb/showthread.php?t=1111483

 

[DS-21]

That works for sealed but not other alignments.

Sure it does, within reason.

For example, one could build an undersized box, "vent" it with a very heavy passive radiator* to get the low-end efficiency up, and use EQ to reduce the Q/take care of the upper-bass peak. (Those two are the same thing.)

*I generally prefer PR's to ports for subwoofers, because I like to tune low. Large-diameter, long pipes have resonance problems.

 

[lsiberian]

*I generally prefer PR's to ports for subwoofers, because I like to tune low. Large-diameter, long pipes have resonance problems.

Not really. The resonance problems are often overstated. Tuning low is often a waste of driver. Some type of loading is necessary for 10-20hz to be effective. I prefer sealed subs for simplicity.

 

[TLS Guy]

Sure it does, within reason.

For example, one could build an undersized box, "vent" it with a very heavy passive radiator* to get the low-end efficiency up, and use EQ to reduce the Q/take care of the upper-bass peak. (Those two are the same thing.)

*I generally prefer PR's to ports for subwoofers, because I like to tune low. Large-diameter, long pipes have resonance problems.

You can't just tune low. You have to tune right and smart, or you get a lousy sub with poor spl and high distortion.

Trying to drive much below Fs is fools gold.

 

[DS-21]

Not really. The resonance problems are often overstated.

My listening experience suggests otherwise.

There's also a reason Dr. Geddes moved from vents to a PR for his bandpass subs. He's not exactly known for preferring a higher-cost approach to something over a lower-cost approach, unless the higher-cost approach offers tangible improvements.

Tuning low is often a waste of driver.

Many drivers, yes.

But there are obvious counterexamples of drivers with very strong motors (low-Q) for efficiency and low resonant frequencies as well. See the Peerless XLS Application Note for one. The LMS Ultra is another that benefits quite a bit (within its passband) from low tuning in terms of bass efficiency.

I prefer sealed subs for simplicity.

I prefer sealed subs too, because they're more tolerant of variance in driver parameters, smaller, and stay monopole so they can pressurize a room below their cutoff. They are less efficient, but multiples bring up the bass system efficiency.

That said, the ancient-at-this-point Peerless XLS12 Application Note design is still one of my favorite compact subs. (Though I typically make them a tiny bit bigger, and tune it a little lower, than the Application Note.) Goes low enough for my program material, sounds really great, and is startlingly efficient for the size.

You can't just tune low.

No, one has to be thoughtful about alignments, though by tuning low with a PR the worst that can really happen is that you'll get no usable efficiency over a simpler closed box of the same size and no useful output below cutoff.

Within its designed-passband, though, it won't be any different in distortion or SPL than the same woofer in the same-sized the closed box.