Subwoofer distortion, measurements and comparisons Discussion

[jostenmeat]

IMO - There is not a whole heck of alot of difference with either driver - both are victim of the horn enclosure, which in all observations shows that distortion is monumental over a standard sealed, ported or LLT scenario.... check out the distortion comparison between them all....

Since you're the guy that finally urged me to buy the DTS10 flatpack when I was trying to pick brains here, perhaps you'd oblige me with some of the qualifiers and the actual distortion comparison measurements. Maybe you're only talking about moderate SPL, or unlimited budget and/or only comparing the best possible versions of each, or maybe not and that you truly mean all observations.

We can all sense differences in output, and can hear differences in decay/overhang, but what distortion levels/percentages are discernible to us with LFE frequencies, and just how far beyond these thresholds do horns get to? I mean I read up on the Fitzmaurice folded horn, and sub-5% distortion . . . is that even perceivable with LFE (honest question)?

 

[Warpdrv]

Since you're the guy that finally urged me to buy the DTS10 flatpack when I was trying to pick brains here, perhaps you'd oblige me with some of the qualifiers and the actual distortion comparison measurements. Maybe you're only talking about moderate SPL, or unlimited budget and/or only comparing the best possible versions of each, or maybe not and that you truly mean all observations.

We can all sense differences in output, and can hear differences in decay/overhang, but what distortion levels/percentages are discernible to us with LFE frequencies, and just how far beyond these thresholds do horns get to? I mean I read up on the Fitzmaurice folded horn, and sub-5% distortion . . . is that even perceivable with LFE (honest question)?

Josten, wasn't ignoring your post, and I think you make a great point, the DTS's are effortless in their efficiency as well as achieving huge SPL's from down low to generally where most people would cross over.... they tend to seemingly show some artifacts from the folding nature of the horn, which comes off as a bit choppy in the response and IMO shows with the THD kinda being all over the map through the entire range if you study the graphs from Data-Bass (raw outdoor GP tests) compared to the Sealed LMS's which are smoother and more predictable in response and THD.... Heck even when Ricci used a TC 12" LMS-R with the linear motor tech, he gained a few dp across the board with the greater excursion but the THD still remained roughly the same in comparison to the stock driver.

Sealed LMS THD

Even the LMS starts to grow in THD when you get to the down lower hz region when the cone behavior starts to pick up in its larger movements.

Now is there enough THD to condemn the DTS's in the normal listening habits scenarios, not likely, but I'm no expert here.... And I can really only go off the graphs as I have never heard one, but from the people I know and trust - they state are smooth, pretty well mannered and don't make themselves stand out. How much THD is too much.... ? I think thats a great question, that has been brought up before - and no real answer or conclusion had been reached from what I recall...

Does the sub work for you, and are you happy with its response, thats all that matters.... If I had the room for them, I would have liked to try them, sure would have been cheaper then the ridiculous route I took, but I'm really thrilled with what I got, and the SQ is like nothing I have heard before.....

 

[Warpdrv]

Another very important thing I didn't mention is these tests are showing max and close to max output with those numbers. Which is a rareity how people are using these products, and lower SPL thd measurements should probably be included to keep things in check IMO.

ILL mention that to Ricci.

 

[GranteedEV]

Another very important thing I didn't mention is these tests are showing max and close to max output with those numbers. Which is a rareity how people are using these products, and lower SPL thd measurements should probably be included to keep things in check IMO.

ILL mention that to Ricci.

with the added 6 - 10 db of sensitivity of a horn you're also pushing your driver a lot less. a lot of people say horns sound better and cleaner than direct radiators at the same volume, so there has to be some truth to it worth investigating.

 

[Warpdrv]

with the added 6 - 10 db of sensitivity of a horn you're also pushing your driver a lot less. a lot of people say horns sound better and cleaner than direct radiators at the same volume, so there has to be some truth to it worth investigating.

yes, that is true, but look how low the distortion is for the LMS at peak SPL until you get down low, and if both are running in normal usage ranges, it would seem to me that either would be a great choice and you get to the point of deciding which you prefer in comparing side by side...

 

[Warpdrv]

copy and paste from the question asked over at AVS from this link.......
http://www.avsforum.com/avs-vb/showthread.php?p=19994333#post19994333

Question that was asked - Which I thought was a good question by Jostenmeat -

We can all sense differences in output, and can hear differences in decay/overhang, but what distortion levels/percentages are discernible to us with LFE frequencies, and just how far beyond these thresholds do horns get to? I mean I read up on the Fitzmaurice folded horn, and sub-5% distortion . . . is that even perceivable with LFE (honest question)?

You will hear different answers....but at 20Hz, I can hear the difference between 5% and 10%, and below 3%, I can't tell anything.

Quoted from Monte Kay's page:

http://www.mfk-projects.com/theatre_woofer.htm


While it is widely accepted in the industry that non linear distortion at low frequency is not particularly audible I am convinced that it is audible. In fact I believe that non linear distortion is the most audible at low frequency. One look at the equal loudness curves of human hearing should convince anyone that non linear distortion is least audible above about 3 KHz and most audible below 3 KHz. Above about 10 KHz it should be completely inaudible because the 2nd harmonic is exceeding the human hearing range. At 20 Hz the human ear will hear an equal level 40 Hz tone as 20 dB louder based on a 90 dB reference level. This means the 40 Hz harmonic must be 20 dB below the 20 Hz fundamental just to sound as if it is the same level or 100% 2nd harmonic distortion.

It's very difficult to achieve low distortion at frequencies in the 20 Hz range. Consequently I wonder how test were conducted to produce the widely held belief that distortion is inaudible at low frequency? Since most woofers produce at least 10% distortion at 20 Hz which sounds like 100% distortion at the 2nd and far higher at the 3rd, they have no clean reference to determine if induced distortion is audible. The test platform is starting with too much distortion to begin with for anyone to assess that an induced distortion is or is not audible.

Until you have a clean reference, you cannot tell.....

I'm going to have Mike seperate this Q&A into a new thread, as we are getting WAY OFF TOPIC from the FUNKY WAVES THREAD....
If you guys would hold off, we can continue over there....