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THX speakers question

1104 Views 22 Replies 11 Participants Last post by J.H., Dec 18, 2005

J.H.

Discussion Starter · Dec 16, 2005

I have a THX processor and AMP and i like having the THX symbol on both. I know that to be THX certified the AMP has to provide enough power and the Processor has to have THX settings and THX post processing. What i don't know is what speakers have to comply with to be THX certified? What paramaters do THX speaker manufactures have adhere to in order to be THX certified? Just a curious question I have Definitive Technology non THX speakers and am not trading them in anytime soon. Thanks J.H.

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1 - 20 of 23 Posts

fergusonv

· #2 · Dec 16, 2005

THX speakers are tested for:

* Axial Frequency Response Analysis

* Directional Characteristics

* Sensitivity

* Impedance

* Harmonic Distortion

* Low Frequency Cut Off

* Phase Angle

* Stray Magnetic Flux

* Maximum Output Level

* Acoustic Noise Level

* Polarity

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J.H.

Discussion Starter · #3 · Dec 16, 2005

thanks great answer. Did you find that on the THX website because i couldn't find it? thanks again J.H.

ekb

· #4 · Dec 16, 2005

THX requirements are proprietary so you won't find them posted. To be a little more specific about speaker requirements they are supposed to have a more limited vertical dispersion than normal. I think it has something to do with hearing dialog more easily since properly aimed speakers will then have a higher direct to reflected sound ratio. Also THX speakers must be sealed, not ported. That way they have a 12 dB/oct roll-off at the bottom end and when combined with a 12 dB/oct electronic high pass filter (ie the Xover), they mate properly in amplitude and phase with the 24 dB/oct low pass filter on the sub. A ported speaker will have a 24 dB/oct roll-off and so never matches as well. Also, since it's 24 dB/octave it needs a lower frequency capability.

Ed

J.H.

Discussion Starter · #5 · Dec 16, 2005

Great post and very technical but i think I get it. I have a question for ya. Do you toe in your front speakers? I always have but to day I put them straight forward not tilted in and I swear it sounds much better. It sounds more like a theater to me. It sounds open and bigger. Am I crazy or not? Whats the proper way straight forward or toed in? Thanks J.H.

NVboy

· #6 · Dec 16, 2005

Quote:

Originally Posted by J.H.
Great post and very technical but i think I get it. I have a question for ya. Do you toe in your front speakers? I always have but to day I put them straight forward not tilted in and I swear it sounds much better. It sounds more like a theater to me. It sounds open and bigger. Am I crazy or not? Whats the proper way straight forward or toed in? Thanks J.H.

Totally depends on the speaker. The only reason you would have to adjust a speaker, be it toe-in or whatever, is to make the owner happy. People tend to toe-in speakers to aim at the primary listening position, aka the sweet spot.

J.H.

Discussion Starter · #7 · Dec 16, 2005

Your are correct sir. I have Definitive technolofy bipolar speakers and i swear it now sounds better. I will have to contact DT to see what they recommend. J.H.

Redskin

· #8 · Dec 16, 2005

Quote:

Originally Posted by J.H.
Your are correct sir. I have Definitive technolofy bipolar speakers and i swear it now sounds better. I will have to contact DT to see what they recommend. J.H.

DT's advice would be great, but don't discount your own ears. Speaker toe-in is highly subjective, and if it sounds better to you, go for it no matter what anyone else says.

J.H.

Discussion Starter · #9 · Dec 16, 2005

Your are correct sir too. I've finally got to the point where I try very unconventional things with my system to make my ears happy not what Dolby,DTS or THX has to say. I do take a lot of stock in what I read on AVS though. In the end the decision in always mine. Thanks J.H.

fergusonv

· #10 · Dec 16, 2005

Here is where I found the info.
http://www.thx.com/mod/products/performance.html

Edit: It aslo lists what is tested on:

DVD Players

PreAmps

Recievers

Power Amps

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Re-Animator

· #11 · Dec 16, 2005

I know a couple of years ago they used B&W 802s for monitors at Skywalker Sound (I don't know if they still do). That means they used non-THX speakers to help create THX mixes for movies, so I don't think you need to get rid of your Def Techs just because they don't have the little badge on them. Keep em if you like the way they sound!

aBlueSky

· #12 · Dec 16, 2005

Quote:

Originally Posted by Re-Animator
I know a couple of years ago they used B&W 802s for monitors at Skywalker Sound (I don't know if they still do). That means they used non-THX speakers to help create THX mixes for movies, so I don't think you need to get rid of your Def Techs just because they don't have the little badge on them. Keep em if you like the way they sound!

I believe the only B&W speakers at Skywalker Sound are the ones used in the scoring stage control room (there could be more, it is a big place and things have changed since I worked at The Ranch). The scoring stage control room has many different types of monitors available for their music / film scoring clients, one of which happens to be the B&W's.

Skywalker Sound also uses several different types of systems for Film Sound Production and they vary depending on the application / room size / monitoring distance etc. To give you an example, applications include; picture editorial, sound editorial, pre-mix, scoring & dub stage.

We have a short user story about Skywalker Sound, and their use of our products, on our website - if you are interested...
http://www.abluesky.com/p_s_gb/p2s2.html

Cheers!

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J.H.

Discussion Starter · #13 · Dec 16, 2005

Oh I aint given up my DTs no way I love Def Techs. J.H.

MaximumBob

· #14 · Dec 17, 2005

Do you have an SPL meter? Toe them in, put them straight, toe them out. I went to a speaker shop and the room they had set up was rectangular in shape and the sound refections dampend out when the speakers were toed in or straight. It kind of looked funny with the speakers pointing slightly at the wall but the sound just opened up.

J.H.

Discussion Starter · #15 · Dec 17, 2005

Of coarse I have a SPL meter. Ever time I use the SPL meter I say "what life saver this thing is". I don't know what i would do without an SPL meter. I recalibrate my speakers every so often just to make sure everything is in line. I'm going to leave the DT's straight forward for a while to see if I like it better so far so good. J.H.

MaximumBob

· #16 · Dec 17, 2005

So does the SPL meter register higher due to the acoustics in the room with them forward or toed in?

J.H.

Discussion Starter · #17 · Dec 17, 2005

Well to get to 85DB straight forward I need a little more power from the amp but not much. To me having the DTs straight forward its better imaging but maybe I'm hearing things. I'll keep it here for a while. Also just to mention Definitive technology recommends toeing the in slightly. So I will just have to experiment. thanks J.H.

dsl1

· #18 · Dec 17, 2005

Quote:

Originally Posted by J.H.
Well to get to 85DB straight forward I need a little more power from the amp but not much. To me having the DTs straight forward its better imaging but maybe I'm hearing things. I'll keep it here for a while. Also just to mention Definitive technology recommends toeing the in slightly. So I will just have to experiment. thanks J.H.

You should be hearing things. If not I would assume something is wrong with your speakers

J.H.

Discussion Starter · #19 · Dec 17, 2005

Very funny and quick. I hear lots of things from my speakers and it ok to hear things from your speakers its not ok to hear things in your head. Then I would say you have problem. J.H.

GPM

· #20 · Dec 18, 2005

Quote:

Originally Posted by ekb
Also THX speakers must be sealed, not ported. That way they have a 12 dB/oct roll-off at the bottom end and when combined with a 12 dB/oct electronic high pass filter (ie the Xover), they mate properly in amplitude and phase with the 24 dB/oct low pass filter on the sub. A ported speaker will have a 24 dB/oct roll-off and so never matches as well. Also, since it's 24 dB/octave it needs a lower frequency capability.

Ed

Greets!

I was researching Klipsch's THX Ultra 2 system today and noticed their larger LCR monitor is vented, so apparently this doesn't de facto keep it from being approved: http://www.klipsch.com/product/produ...ue&rmore=False

GM

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