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Gooddoc's Avatar Gooddoc 05:13 PM 05-01-2014
Quote:
Originally Posted by Nyal Mellor View Post

I've written quite a bit about speaker off axis on my blog recently. I'm up to 5 articles now that cover speaker off axis, how to measure, psychoacoustic importance and then looking at the off axis response of different speaker types and their impact on room acoustic treatment.
Thanks Nyal. Very well written and informative articles.

HToutofoffice's Avatar HToutofoffice 06:36 PM 05-01-2014

Dang dese Triple 12's are flippn of the charts, so clear and dynamic at high volume. Really makes me cringe to think of other speakers for home theater.


MiniHT's Avatar MiniHT 07:03 PM 05-01-2014
Man, I feel so left out with my "puny" S8's as an LCR... someone upgrade to 212's/T12's or 15's so you can donate some 228's/T8's to South Jersey... tongue.gif BTW, congrats HT, how long have you had the T12's?
HToutofoffice's Avatar HToutofoffice 07:09 PM 05-01-2014
Quote:
Originally Posted by MiniHT View Post

Man, I feel so left out with my "puny" S8's as an LCR... someone upgrade to 212's/T12's or 15's so you can donate some 228's/T8's to South Jersey... tongue.gif BTW, congrats HT, how long have you had the T12's?

 

I got em threw canuck canada last year, but only really got em installed now.


Gooddoc's Avatar Gooddoc 07:19 PM 05-01-2014
Quote:
Originally Posted by MiniHT View Post

Man, I feel so left out with my "puny" S8's as an LCR... someone upgrade to 212's/T12's or 15's so you can donate some 228's/T8's to South Jersey... tongue.gif BTW, congrats HT, how long have you had the T12's?

Those S8's are amazing little boxes. Keep an eye out, maybe someone will have some 212's up for sale soon...
jlpowell84's Avatar jlpowell84 07:38 PM 05-01-2014
Quote:
Originally Posted by MiniHT View Post

Man, I feel so left out with my "puny" S8's as an LCR... someone upgrade to 212's/T12's or 15's so you can donate some 228's/T8's to South Jersey... tongue.gif BTW, congrats HT, how long have you had the T12's?

I'm rolling Triple 8's LCR and feel inferior at times. But then again I hit play and know I have a VERY VERY capable speaker. Really the difference is just a bit higher SQ...I have gone higher SPL than my ears can stand (hopefully no damaged hearing, could be from my AR 15 without an earplug, oops!) and there is not an inkling of strain and they sound great with my Submersives! smile.gif I know there is higher SQ out there as the Triple 8's don't grab me with music like I have heard about the Noesis but I and and you are sitting pretty good compared to the rest of the HT world out there (JBL home line stuff) and so are you! I always remember how RMK glorified the Triple 8's and Single8's on LCR duty while he was in transition from his 212's to 215's and gave them the utmost praise as capable good SQ speakers. smile.gif Gotta keep our eye on the positive!
jlpowell84's Avatar jlpowell84 07:42 PM 05-01-2014
Quote:
Originally Posted by Nyal Mellor View Post

Yeah, depends how far the speaker are from the front wall. 4ft gets you a nice cancellation around 80Hz. Closer you push up the reflection into the 100-200Hz range.

Path length difference for direct vs reflected sound, ft = 1130 / (2 * cancellation frequency, Hz). Learn more here: http://redspade-audio.blogspot.com/2011/02/sbir-speaker-boundary-interference.html.

Once you've heard what a baffle wall to the quality of your 50-200Hz bass IMO there is no going back.

Here's the one I did for DBeck's Savoy:


So my Triple 8 L&R are 21.5 inches from the wall and 17.5 with the 4 inch Roxul AFB panel. Does this panel help with these mid bass issues? Should I create some absorption for behind my center channel as well?
jlpowell84's Avatar jlpowell84 07:46 PM 05-01-2014
Quote:
Originally Posted by RMK! View Post

Thanks DD, I would only add that my back wall is a combination of absorption (GIK 244's) and diffusion panels. Making my room more on the dead side (eg no slap echo). Before I treated the ceiling and back wall Keith Yates demonstrated the sound transmission in the room by talking and changing positions. It was at his suggestion that I treated the front wall, the ceiling and back wall. He went against the conventional wisdom by being less concerned about side walls which is where most put their absorption. I had panels there at the first and second reflection points on the side walls and as I said, my room is if anything, over treated. I like the sound and it measures well so I'm staying the course with a true baffle wall being the only modification I might consider.

Nice Rob, With my recent treatment overtime hours (fully treated room minus some bass traps) the last Audyssey cal I ran the chirps had zero echo at all. I could tell it was a HUGE difference in taming reflections just by what my ears where hearing. The ceiling 24x96 panel taming the LCR reflections at both seats (yes only two, well a third that is never used) made a huge difference! It seems a baffle wall is your next path of progression and what I WILL certainly do when I buy a home smile.gif
jlpowell84's Avatar jlpowell84 07:54 PM 05-01-2014
Quote:
Originally Posted by carp View Post

Da*n...

Just when I think I know something is right 100%...

What about ceiling panels for the 1st reflections?

The ceiling is massively important as very early reflections at high db (like 10-15 milliseconds of -5 to-10db reflections can occur). I have read, lots of research, the ceiling has proved to be the single most beneficial treated area in several peoples HT's.

Here is my 2xs24x96 Roxul AFB ceiling treatment with strategic renters installation. The cover of the fluorescent light was removed and screws into the metal frame were inserted with .75x96 pine strips as mounting base. It is not visible with the light cover installed. Just one drywall female screw hole and eye hook was inserted off to the right to keep it from sagging as the light fixture is obviously non symmetrical to the left. Covered in the white most burlap we could find. It blends well as far as not noticing it at all. I used the mirror technique to identify the areas that needed covered for both seats from all LCR speakers. I will go into much more depth in the thread I plan on creating soon. Life and OT have gotten in the way!



jlpowell84's Avatar jlpowell84 08:00 PM 05-01-2014
Quote:
Originally Posted by staaled View Post

Toole also states that first reflections from the sides are actually beneficial for ASW ( apparent source width) and LEV ( listener envelopment).
The front wall can then be treated with absorbtion/ some diffusion and rear with diffusion.

I have read this as well and have come to the conclusion it can be either room specific or listener preference or even goal specific.
jlpowell84's Avatar jlpowell84 08:10 PM 05-01-2014
Quote:
Originally Posted by craig john View Post

No matter what Toole says, there is no circumstance where I, (personally), prefer an added reflection... any added reflection, no matter where it comes from. I would much rather listen to the "direct" sound of my speakers than the reflected sound from my room. In fact, I consider anything added by my room to be "distortion." And in the strictest sense, it is. It's something added that is not in the original signal. Some people "like" the distortion of tube amps. Some like the distortion of lots of reflections in their rooms. I, (personally), prefer neither. Some reflections can't be avoided, and I prefer those reflections to be late in arrival and at a lower level.

Craig

Interesting perspective! I tend to agree more than not. I had a couple leftover panels after my ceiling treatment took another route from a couple 4x24x48 panels that I place in the rear area that has a computer desk and dining table that is never used. I knew they would deal with late reflections. I also built a small panel for a cabinet end as well. I am liking this direct sound and zero echo smile.gif It just feels very pure and untainted is the best way to describe. I volunteer on tuesday nights at a church recovery meeting running media setup. We have a very talented live band with electric guitars, harmonicas, bass guitar, drums of course, electric piano, numerous vocals, and saxophone. The sound in that room is very "live" sounding. I think it sounds good and all compared to some over deadened rooms I have been in but I feel my room, and I suspect yours, have the right amount that is in the middle ground.
jlpowell84's Avatar jlpowell84 08:11 PM 05-01-2014
Quote:
Originally Posted by logicators View Post

That made all the difference in my basement theater. I had some nasty nulls and low frequency ringing that simply wouldn't go away after applying front, back and side wall treatments (8" thick floor to ceiling bass traps in all the corners, plus 2 more 4" deep floor to ceiling bass traps on side walls with 4" air gap and 4" panels for the first reflection points on the side walls).

I then added a 2 panels x 2 panels grid of 2'x4' 4" Roxul rockwool tiles (it's a drop ceiling), so essentially covered a 4 feet by 8 feet area that covers the first ceiling reflection points of all 3 front speakers. The quality improvement was instantaneous, but audibly and in measurements. Before adding the ceiling treatments audyssey always selected a 90 or 100 Hz crossover for my 212s. It now selects 60 Hz for left and right and 40 Hz for the center (which I bump up to 60). The dialog clarity improved to an extent that other members of my family noticed and mentioned it.

I should have read further lol!!! biggrin.gif

Damn Red Hook Longhammer IPA!
jlpowell84's Avatar jlpowell84 08:16 PM 05-01-2014
Quote:
Originally Posted by RMK! View Post

Sounds fishy to me ...A sealed alignment like this in the smaller cabinet with high excursion woofers will create a destructive back wave that will cause unwanted modulation in the CD. This will lead to HF breakup of epic proportions with inverse polars and sound fragmentation.

You simply can't go around violating the laws of Physics without consequences ...

Wow that was like Will Farrell at his debate...

https://www.youtube.com/watch?v=e-NQSAL-c0c
jlpowell84's Avatar jlpowell84 08:17 PM 05-01-2014
Quote:
Originally Posted by N8DOGG View Post

If Jeff sealed the CD area, it could work well.

Exactly, just like my old school updated Triple 8's. They had the sealed middle cab...
Nyal Mellor's Avatar Nyal Mellor 08:29 PM 05-01-2014
Quote:
Originally Posted by craig john View Post

No matter what Toole says, there is no circumstance where I, (personally), prefer an added reflection... any added reflection, no matter where it comes from. I would much rather listen to the "direct" sound of my speakers than the reflected sound from my room. In fact, I consider anything added by my room to be "distortion." And in the strictest sense, it is. It's something added that is not in the original signal. Some people "like" the distortion of tube amps. Some like the distortion of lots of reflections in their rooms. I, (personally), prefer neither. Some reflections can't be avoided, and I prefer those reflections to be late in arrival and at a lower level.

Craig

So you are listening in a massive anechoic chamber then? If not you still have reflections smile.gif
Nyal Mellor's Avatar Nyal Mellor 08:30 PM 05-01-2014
Quote:
Originally Posted by RMK! View Post

Sounds fishy to me ...A sealed alignment like this in the smaller cabinet with high excursion woofers will create a destructive back wave that will cause unwanted modulation in the CD. This will lead to HF breakup of epic proportions with inverse polars and sound fragmentation.

You simply can't go around violating the laws of Physics without consequences ...

Aren't the CDs air sealed by nature of their construction from the back wave?
Nyal Mellor's Avatar Nyal Mellor 08:31 PM 05-01-2014
Quote:
Originally Posted by jlpowell84 View Post

The ceiling is massively important as very early reflections at high db (like 10-15 milliseconds of -5 to-10db reflections can occur). I have read, lots of research, the ceiling has proved to be the single most beneficial treated area in several peoples HT's.

Fully agree, and you know why? It's because most speakers are vertically stacked arrangements of drivers. Look at vertical off axis measurements and you can see some severe nulls and lobing. Speakers can look quite nice in the lateral domain but be horrible vertically.
jlpowell84's Avatar jlpowell84 08:39 PM 05-01-2014
Quote:
Originally Posted by Nyal Mellor View Post

Fully agree, and you know why? It's because most speakers are vertically stacked arrangements of drivers. Look at vertical off axis measurements and you can see some severe nulls and lobing. Speakers can look quite nice in the lateral domain but be horrible vertically.

Nice! I love learning more about this stuff. I have JTR Triple 8's so obviously three drivers vertically and slightly just a tad on the higher than center side vertically. When first learning about treatments I always thought the panels needed to be directly above me but boy was I wrong.
lbrown105's Avatar lbrown105 11:05 PM 05-01-2014
Quote:
Originally Posted by Nyal Mellor View Post

Yeah, depends how far the speaker are from the front wall. 4ft gets you a nice cancellation around 80Hz. Closer you push up the reflection into the 100-200Hz range.

Path length difference for direct vs reflected sound, ft = 1130 / (2 * cancellation frequency, Hz). Learn more here: http://redspade-audio.blogspot.com/2011/02/sbir-speaker-boundary-interference.html.

Once you've heard what a baffle wall to the quality of your 50-200Hz bass IMO there is no going back.

Here's the one I did for DBeck's Savoy:

Must be late, but I am not following why 4ft gives 80 hz null by this equation. 1130/2*(80hz)=appox 7.1ft. Please clarify
coolgeek's Avatar coolgeek 04:54 AM 05-02-2014
Quote:
Originally Posted by jbrown15 View Post

I posted the same thing like three weeks ago saying it would be cool to see an LCR version rather then full towers and guys thought I was crazy for suggesting that.....lol

I just thought it would be cool to see some serious bad A$$ LCR's that didn't need to go down to 20hz like the 215RT's but would still give you that "kick you in the chest" mid bass slam. I sure something like that would have way more mid bass then the 212HT's. And you could still use the Cap S2's for the ultra low stuff.

I have a feeling something like this sealed going down to 50 ro so and coupled with the s2s would be my perfect setup. Should have all the mid bass slam anyone need.
coolgeek's Avatar coolgeek 05:00 AM 05-02-2014
Quote:
Originally Posted by jlpowell84 View Post

Interesting perspective! I tend to agree more than not. I had a couple leftover panels after my ceiling treatment took another route from a couple 4x24x48 panels that I place in the rear area that has a computer desk and dining table that is never used. I knew they would deal with late reflections. I also built a small panel for a cabinet end as well. I am liking this direct sound and zero echo smile.gif It just feels very pure and untainted is the best way to describe. I volunteer on tuesday nights at a church recovery meeting running media setup. We have a very talented live band with electric guitars, harmonicas, bass guitar, drums of course, electric piano, numerous vocals, and saxophone. The sound in that room is very "live" sounding. I think it sounds good and all compared to some over deadened rooms I have been in but I feel my room, and I suspect yours, have the right amount that is in the middle ground.

Now I am more confused than ever. When I said I was going to put roxul all around my walls and absorbs everything everyone tells me it's a no no. That I would need some diffusers. Else my room would sound dead. So what is true? I need to get right
staaled's Avatar staaled 06:12 AM 05-02-2014
Quote:
Originally Posted by coolgeek View Post

Now I am more confused than ever. When I said I was going to put roxul all around my walls and absorbs everything everyone tells me it's a no no. That I would need some diffusers. Else my room would sound dead. So what is true? I need to get right

"Live end -dead end" is a valued approach.
So front wall absorbtion , rear wal diffusion.
The sides you can treat with either , where my choice would be not to absorb refelections from the nearest speaker in stereo but go for the 1st reflection of the opposing one to lessen crosstalk.
coolgeek's Avatar coolgeek 07:52 AM 05-02-2014
Quote:
Originally Posted by staaled View Post

"Live end -dead end" is a valued approach.
So front wall absorbtion , rear wal diffusion.
The sides you can treat with either , where my choice would be not to absorb refelections from the nearest speaker in stereo but go for the 1st reflection of the opposing one to lessen crosstalk.

Ok. Dead front then. And half half sides... if I have carpets what to do with ceiling?
jlpowell84's Avatar jlpowell84 08:40 AM 05-02-2014
Quote:
Originally Posted by coolgeek View Post

Now I am more confused than ever. When I said I was going to put roxul all around my walls and absorbs everything everyone tells me it's a no no. That I would need some diffusers. Else my room would sound dead. So what is true? I need to get right

You need to systematically and scientifically place panels for dealing with specular reflections. Just throwing up panels where you "think" is good and never measuring or being sure you need absorption there is a huge mistake. You can do the mirror technique on the walls and ceiling to find your reflection points and treat. That way you "technically" would never have to measure with REW and you can still be "mostly" sure you are dealing with specular reflection points. So bass trapping is easy in the corners the reflection points is other part of treating and needs done scientifically. Too many panels will over deaden your room and become unpleasant. You want to keep some of the liveness which is why some integrate diffusion in. make sense?
coolgeek's Avatar coolgeek 09:18 AM 05-02-2014
Quote:
Originally Posted by jlpowell84 View Post

You need to systematically and scientifically place panels for dealing with specular reflections. Just throwing up panels where you "think" is good and never measuring or being sure you need absorption there is a huge mistake. You can do the mirror technique on the walls and ceiling to find your reflection points and treat. That way you "technically" would never have to measure with REW and you can still be "mostly" sure you are dealing with specular reflection points. So bass trapping is easy in the corners the reflection points is other part of treating and needs done scientifically. Too many panels will over deaden your room and become unpleasant. You want to keep some of the liveness which is why some integrate diffusion in. make sense?

Thanks JL,

So, absorb first reflections, and then diffuse others? Rule of thumb?

Actually I have a similar question as Archaea...

For the frontstage, it's prob the only BIG space behind the screen that I can do bass trap. If i do a typical thx type 'hard' baffle to surround my speakers, then won't i be wasting the 4 feet of space behind that baffle for bass trap? So, it's either do a baffle or a bass trap, right?

So, my plan right now:

1. Dead front-stage (but not sure if i do the baffle or not)
2. first reflection point roxul / pink fluffy
3. Back wall and secondary reflections, diffuse
4. Ceiling, plywood with holes and roxul behind (in case sound do get up above to the kitchen.
5. Riser (thought of using it as bass trap as well and if i do, i am leaving the entire front part opened (12 inches from floor up), and then fill the entire inside with roxul or pink fluffy)
6. floor - carpet... not sure if i should do wood first then carpet (as it's concrete floor) or just carpet alone.
RMK!'s Avatar RMK! 09:44 AM 05-02-2014
Since you are building out a new dedicated room, professional assistance would be nice. smile.gif Nyal or the Erskine Group could give you a a turnkey treatments plan.
Quote:
Originally Posted by coolgeek View Post

Thanks JL,

So, absorb first reflections, and then diffuse others? Rule of thumb?

Actually I have a similar question as Archaea...

For the frontstage, it's prob the only BIG space behind the screen that I can do bass trap. If i do a typical thx type 'hard' baffle to surround my speakers, then won't i be wasting the 4 feet of space behind that baffle for bass trap? So, it's either do a baffle or a bass trap, right?

So, my plan right now:

1. Dead front-stage (but not sure if i do the baffle or not)
2. first reflection point roxul / pink fluffy
3. Back wall and secondary reflections, diffuse
4. Ceiling, plywood with holes and roxul behind (in case sound do get up above to the kitchen.
5. Riser (thought of using it as bass trap as well and if i do, i am leaving the entire front part opened (12 inches from floor up), and then fill the entire inside with roxul or pink fluffy)
6. floor - carpet... not sure if i should do wood first then carpet (as it's concrete floor) or just carpet alone.

craig john's Avatar craig john 10:05 AM 05-02-2014
Quote:
Originally Posted by staaled View Post

Like I said , lateral refelections influence these two.
It is a matter of preference then.
Most people find it pleasing and rate it higher.

Professional listeners, ,recording etc., want and like a short decay time to hear better into the recording.
Toole agrees with the "preference" thing:
Quote:
The real solution, for professionals as well as consumers, is loudspeakers that deliver similarly good timbral accuracy in the direct, early reflected and reverberant sound fields. This can be described as a loudspeaker with a flattish, smooth, axial frequency response, with constant directivity (which together result in flattish, smooth, sound power).

Then it becomes an option, whether the room is acoustically damped, or not.

If reflected sounds are absorbed, the listener is placed in a predominantly direct sound field, making the experience more intimate, and the imaging tighter and more precise.

If the reflections are allowed to add their complexity, the overall illusion is altogether more spacious and open, to many listeners, more realistic.

In part, this is a matter of taste.
http://www.harmanaudio.com/all_about_audio/acoustical_design.pdf

Craig
craig john's Avatar craig john 10:09 AM 05-02-2014
Quote:
Originally Posted by craig john View Post

No matter what Toole says, there is no circumstance where I, (personally), prefer an added reflection... any added reflection, no matter where it comes from. I would much rather listen to the "direct" sound of my speakers than the reflected sound from my room. In fact, I consider anything added by my room to be "distortion." And in the strictest sense, it is. It's something added that is not in the original signal. Some people "like" the distortion of tube amps. Some like the distortion of lots of reflections in their rooms. I, (personally), prefer neither. Some reflections can't be avoided, and I prefer those reflections to be late in arrival and at a lower level.

Craig

Quote:
Originally Posted by Nyal Mellor View Post

So you are listening in a massive anechoic chamber then? If not you still have reflections smile.gif

Nyal, please see the emphasized text above.
coolgeek's Avatar coolgeek 10:11 AM 05-02-2014
Quote:
Originally Posted by RMK! View Post

Since you are building out a new dedicated room, professional assistance would be nice. smile.gif Nyal or the Erskine Group could give you a a turnkey treatments plan.

RMK..

I wish i have the money... I am totally over-budgeted... not just the home theater aspect, but building the entire house... digging deep into my savings...

I did pay GikAcoustics for a plan, it seems simple... but requires the purchase of their products which is not possible to ship to Malaysia... So, i have been reading up a lot on acoustics thread, etc.. and have came up with a simple plan.

Also, I have been to many 'Theater' and 'Audio' rooms designed by 'local experts' and they all don't sound good to me... it seems my natural room with bookshelves sounded better..

I guess, after reading a lot, perhaps, just throwing things around, quasi science, may do the job.. smile.gif

I know people here hate' quasi science' and me too, really, but budget doesn't allow it... proper acoustics from experts will cost me way too much, and perhaps take away the budget i have for the projector...
staaled's Avatar staaled 10:34 AM 05-02-2014
Quote:
Originally Posted by craig john View Post

Toole agrees with the "preference" thing:
http://www.harmanaudio.com/all_about_audio/acoustical_design.pdf

Craig
Part no choice part preference I am somewhere in the middle I guess.
I tried two extra GIK 244' s on my front wall recently.
At first I liked the result, but after a while I found it sounded a bit dull , bordering boring.biggrin.gif
So now I am back to my preferred distortion.wink.gif
Tags: 228ht , captivator , Jtr , Jtr Noesis 212ht 212ht Lp
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