SVS subs are just another sub with "box alignment " (1 Viewer)

[Doug_Z]

Does anyone with more knowledge than I possess, about subs, want to argue against the statement made on another forum that SVS subs would not meet THX Ultra 2 certification because of their "box alignment" design.The address is:

Link Removed

Sorry I'm not computer literate enough to insert a link.Yes I started the thread on the other forum. I would like to defend SVS further but I lack the expertise.

 

[Doug_Z]

The link does not appear to work. The Forum can be easily found by going to google and entering "Flagship receiver Central". The topic is under the Denon 5803 forum and the topic refers to Thx Ultra 2 sub settings.

The link in my first post will now take you to the flagship central forum. Just click on Denon 5803. The topic is titled "THX Ultra 2 sub settings"

 

[Wayne_T]

Edit your post, losing the "." at the end of the URL, and then I think your link will work.

 

[Dustin B]

Well the guy needs to learn his terminology a little better. Box allignment is meaningless. Bass reflex allignmnet is what I think he meant and that is what an SVS sub is. There is not reason a bass reflex design can't sound great, and the Ultra does.

Next the Ultra is definately not a high Q allignment. To the contrary it is a very low Q allignment that is very flat, even at high levels down very low. Most people used to high Q subs are very disappointed at first with an SVS because they are used to the peak he speaks of. The Ultra just gives clean deep bass. I have no doubt that an Ultra would easily out perform that Jamo sub that is certified THX Ultra2.

SVS knows this, is a small company and doesn't care to increase their products prices in order to pay for a THX certification.

Don't worry too much about THX. For the most part it is over rated. There are a number of bad products certified, and there are many excellent products that aren't certified. From what others said in that thread I would set the Ultra2 mode to yes to disable the peak limiter. Then turn off the boundary gain compensation and pick up a Behringer FeedBack Destroyer (or some other decent parametric EQ) to properly equalize the sub for a flat or room curver response rather than relying on a set THX curve that likely will not match what is going on in your room.

 

[Ned]

Boundary Gain Compensation = rolls of the bass from 55 Hz (-3 dB point) and below, and is down by -10 dB @ 20 Hz

Quoted from that other forum about the THX boundary adjustment. What kind of nonsense rubbish feature is this? Sounds like an overly aggressive highpass filter to protect the wussy THX Ultra 2 subs that can't actually handle the job

That espen person is amusingly clueless.

 

[Reginald Trent]

As a owner of a SVS 16-46pci I'm not sure what the point of this thread is. However, I'll ask which subs meet THX specs and do they outperform SVS subs? I think we already know the answer but I'll wait for someone to confirm.

 

[Doug_Z]

Reginald: The purpose of this post was to tap into the great wealth of knowledge on this forum concerning subs in general and SVS subs in particular. I own an Ultra thanks in part to this forum. It's an awesome piece of equipment.

When I posted the question on the other forum it irritated me that the one poster was giving out bad information about SVS subs. I guess I felt a need to defend SVS since my dealings with then have been so positive. I can't imagine defending another company the same way.

The problem is that I lacked the technical knowledge to respond to his post which discusses box alignment subs....... etc. I came to this forum in hopes you guys could help respond to this guy.He makes professor backwards sound lucid. However,that opinion is only my hunch and not based on any expertise. Thus this Post. By the way he is a very frequent poster and at least acts like he knows what he is talking about.I know SVS is a small company and I don't mind setting others straight about them.This guy seems very confused,at least about SVS.

 

[Dan Hine]

Do a search on this forum for posts by Espen Braathen. You'll find that many of his opinions are unfounded and his arguments are easily refuted. I've almost gotten to the point where I skip right over his posts.

 

[Edward J M]

Don't worry too much about THX. For the most part it is over rated. There are a number of bad products certified, and there are many excellent products that aren't certified.

Amen, Dustin. Thanks for being a consistent voice of reason and a reality check.

 

[Bill Law]

Then what specific impact would enabling the "THX Ultra 2 sub" on my Pioneer 49TXi have?
The manual doesn't say.
Are there certain performance parameters that you could check to determine if a sub meets the spec unofficially?

 

[Doug_Z]

Bill: No One knows the answer to your last question. At least no one willing to post on this or other forums.I guess it's because THX does not publish their specifications.Thus, it's not as simple as I would like it to be.

If the specs were published or at least well known,the performance of non THX certified subs could be measured and compared. They would either meet the specs or not. You would then know whether your sub met THX specs, even though it would not in fact be THX certified.THX obviously does not want SVS or other subs, that would very likely meet the specs, to test their subs since the word would get out. If a sub really does meet THX specs then why pay extra just for the certification.

It is still very irritating to me that when it comes to the THX sub setting on a THX Ultra 2 pre/pro or receiver you really don't know whether you should set the s/w thx ultra 2 to yes or no and much more importantly what effect the Boundary gain compensation "on" has on the preformance of the sub. I hope SVS or someone on this forum will get a THX Ultra 2 certified pre/pro/receiver and measure exactly what the BGC does from 55HZ and below.

As I said before Tom at SVS believes (but is not sure) that BGC attenuates the the signal slightly at below 30 Hz. That would be fine with me. However, the poster on the other forum which I referred to above thinks that the bass is rolled off at 55 Hz and below and the output is down -10dB at 20Hz. He says it's "just common sense". I guess we should just take the sage advice of a couple of the posters above and say who cares.

 

[Dan Hine]

As I said before Tom at SVS believes (but is not sure) that BGC attenuates the the signal slightly at below 30 Hz. That would be fine with me. However, the poster on the other forum which I referred to above thinks that the bass is rolled off at 55 Hz and below and the output is down -10dB at 20Hz.

If you want, pick up a test cd from Stryke or Parts Express with test tones from 20hz-99hz. The tones are given their own track numbers (ie track 20 is a 20hz tone) so you can easily plot the response. Take the measurements with and without BGC and see how they compare.