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One better sub or two subs - Page 23

post #661 of 757
Quote:
Originally Posted by SherazNJ View Post


But including splitters did what my room couldn't. I gave me that extra elivation that I was looking for. Thanks so much for bringing splitters in the mix.

Simply turning up the sub level on the subs or in your receiver will give you the same result.  All you did was add more wiring into your system.

post #662 of 757
Quote:
Originally Posted by braveheart123 View Post

That's strange then. Feeding both L/R inputs on each sub in your room should lift the FR by 6-7dB collectively from 80Hz all the way down to whatever point your subs roll off without changing any other configuration.
Then engaging LPF on both of them at 50Hz should bring the already elevated 50-80hz region down by roughly the same amount bringing the response in that region at par with speakers. Seems like one of your subs goes out of phase. You tried this with one sub and it worked. When you engaged both; the response dipped badly.

The 6-7db would be in a perfect world.  Like you said, phase issues are more than likely the difference.  Isn't the only response with the dip the one where he induced it by setting the sub LPF to 50hz?

post #663 of 757
Quote:
The 6-7db would be in a perfect world. Isn't the only response with the dip the one where he induced it by setting the sub LPF to 50hz?

You may be right on this. His is huge room with ample leaks. Mine is only 1700 cu ft with roughly 8-9dB room gain. But I need to run the FR and see how cascading LPF turns out in my room. I've measured my sub yielding roughly 7dB by feeding both L/R inputs.
post #664 of 757
Thread Starter 
Quote:
Originally Posted by primetimeguy View Post

Simply turning up the sub level on the subs or in your receiver will give you the same result.  All you did was add more wiring into your system.

My experience says the other way though. Please see post http://www.avsforum.com/t/1490184/one-better-sub-or-two-subs/630
I posted graph there showing the difference. If I were to increase gain sub, It would lift the whole graph from crossover all the way down. Then when I tried to get 10db diff from 30-80 (crossover), it'd bring crossover way below as compared to 100Hz. Furthermore, I wasn't able to bring subs to that high in 30 hz area. I might have if I increased subtrim to 4-5 db more in subtrim but that could very well have cause distortion as well. I got the results I was looking for without changing subtrim.

Are you saying that
Using Y-Splitter = Increase gain in subtrim 4db?
and the result will exactly be the same even though we are increasing sub gain that much?
post #665 of 757
Quote:
Originally Posted by SherazNJ View Post


My experience says the other way though. Please see post http://www.avsforum.com/t/1490184/one-better-sub-or-two-subs/630
I posted graph there showing the difference. If I were to increase gain sub, It would lift the whole graph from crossover all the way down. Then when I tried to get 10db diff from 30-80 (crossover), it'd bring crossover way below as compared to 100Hz. Furthermore, I wasn't able to bring subs to that high in 30 hz area. I might have if I increased subtrim to 4-5 db more in subtrim but that could very well have cause distortion as well. I got the results I was looking for without changing subtrim.

Are you saying that
Using Y-Splitter = Increase gain in subtrim 4db?
and the result will exactly be the same even though we are increasing sub gain that much?

Which chart compares using the y-splitter vs not with a +4db sub trim?

 

Yes, I'm saying when you use the Y-splitter the sub sees two inputs and sums them therefore yielding a net gain.  You could get the same gain from increasing your volume/gain on the sub or the trim level in the AVR.  There isn't some "magical" gain or difference created by using the y-splitter, just a different way to obtain the gain.

post #666 of 757
Quote:
Originally Posted by primetimeguy View Post

Which chart compares using the y-splitter vs not with a +4db sub trim?

Yes, I'm saying when you use the Y-splitter the sub sees two inputs and sums them therefore yielding a net gain.  You could get the same gain from increasing your volume/gain on the sub or the trim level in the AVR.  There isn't some "magical" gain or difference created by using the y-splitter, just a different way to obtain the gain.
it's only +3db.
it happens with y splitter because the signal from the left and right channel are summed to a single mono signal for the sub.
post #667 of 757
Thread Starter 
Quote:
Originally Posted by primetimeguy View Post

Which chart compares using the y-splitter vs not with a +4db sub trim?

Yes, I'm saying when you use the Y-splitter the sub sees two inputs and sums them therefore yielding a net gain.  You could get the same gain from increasing your volume/gain on the sub or the trim level in the AVR.  There isn't some "magical" gain or difference created by using the y-splitter, just a different way to obtain the gain.
Quote:
it's only +3db.
it happens with y splitter because the signal from the left and right channel are summed to a single mono signal for the sub

OK then it means that the graph should come up to same level all around (from crossover to all they way down) if I were to increase subtrim gain to 3db?
post #668 of 757
Yes
post #669 of 757
Thread Starter 
Quote:
it's only +3db.

I tested with and without splitter and its 4db of difference. So using Y-Splitter gives you a 4db of gain.
One concern I have/had is that using more db can cause bass quality? I listened to some scenes with -6db sub trim then with -4db trim and then with -5db trim with y-splitter using dsp(which brings subtrim to -1). There was no distortion in bass. In case if anyone is wondering why I'm keeping subtrim to -5 with Y-Splitter (in other words: subtrim to -1), its not because I wanted that high bass but because I wanted to have a 10db of hard-knee curve and wanted crossover to be at same level or higher than frequencies higer than it (90-100 ......). Moving subtrim to -1 gets me exactly there. My concern is then again if it can end up reducing bass quality? I absolutely love how low bass scenes sound (specially the suspense scenes). I did some testing with bass demo disk and had no distortion.

So the question is "If we increase subtrim on avr, does it increases the bass but does it cause lower bass quality?
post #670 of 757
Quote:
Originally Posted by SherazNJ View Post


I tested with and without splitter and its 4db of difference. So using Y-Splitter gives you a 4db of gain.
One concern I have/had is that using more db can cause bass quality? I listened to some scenes with -6db sub trim then with -4db trim and then with -5db trim with y-splitter using dsp(which brings subtrim to -1). There was no distortion in bass. In case if anyone is wondering why I'm keeping subtrim to -5 with Y-Splitter (in other words: subtrim to -1), its not because I wanted that high bass but because I wanted to have a 10db of hard-knee curve and wanted crossover to be at same level or higher than frequencies higer than it (90-100 ......). Moving subtrim to -1 gets me exactly there. My concern is then again if it can end up reducing bass quality? I absolutely love how low bass scenes sound (specially the suspense scenes). I did some testing with bass demo disk and had no distortion.

So the question is "If we increase subtrim on avr, does it increases the bass but does it cause lower bass quality?

No, you are just changing the level not the "quality".  Unless you get too high and the sub distorts then I guess you'd be affecting the quality.  Otherwise you are just adjusting to your personal preference and nothing wrong with that.

post #671 of 757
Thread Starter 
Quote:
Originally Posted by primetimeguy View Post

No, you are just changing the level not the "quality".  Unless you get too high and the sub distorts then I guess you'd be affecting the quality.  Otherwise you are just adjusting to your personal preference and nothing wrong with that.
Aewsomeeeeeee. Time for watching some movie scenes :-) I"ll let you guys know how it went. Now I'm worried too much about my room giving the gain since I got the hard-knee curve and the lower bass scenes sound great :-)
post #672 of 757
Thread Starter 
Instead of listening to Bass demo disk, I decided to watch LOTR (first part) to check how it'd sound normally. It sounds great. In fact, I had to reduce sub trim from -4 to -7 because the bass was getting overwhelming. This is something I thought I'd not be able to say based on my room gain but things have changed. I reduced sub trim not because bass was getting distorted but because it was too strong. Even at -7 subtrim (with splitter included), it still gets a bit overwhelming sometimes but I'm absolutely loving it. It easily can scare me. I hear all the details. So far so good.
post #673 of 757
Thread Starter 
Today I went to IMAX to watch Hunger Games part 2. My main motivation was to listen to IMAX theater. But this time after spending so much time trying to get good sound out of my home theater, I wanted to go and pay full attention to how IMAX sounds. Yes we all know it sounds amazing but this time it was different since I wanted to listen to IMAX as a reference. One thing I noticed right away that all the speakers in IMAX sound equally. I mean not just the front but the side and read also sound equally loud. Bass was amazing and never was overwhelming. It was very warm sound. Even though bass never felt too loud yet I could feel it in the heart time to time.

So what's the grand secret of IMAX great sound???? Also do any of you have same speakers for all around (front side and back)?
post #674 of 757
Quote:
Also do any of you have same speakers for all around (front side and back)?

For all channel stereo application, having same speakers all around does have sonic benefits. But it's waste of resources for HT application coz every speaker gets different signal. More over in DD/DTS, surrounds get ambient sounds for most part of the movie. Some nuts here do have same speakers all around, though.

One more thing, IMAX is a purpose-built cinema with heavy acoustic treatments and array of subs not just 1, 2, or 3.
post #675 of 757
Per-channel EQ really helps timbre match surrounds, except for dipoles.
post #676 of 757
Thread Starter 
considering the fact that my rear speakers are the weakest (smallest) and also farthest (14 feet) away from MLP, would it be better if I were to mount them on the ceiling close to MLP?
post #677 of 757
Distance doesn't matter; placement does. As long as your surrounds are level matched with the rest of the speakers; it's all good.
post #678 of 757
Thread Starter 
Quote:
Originally Posted by braveheart123 View Post

Distance doesn't matter; placement does. As long as your surrounds are level matched with the rest of the speakers; it's all good.
Thanks braveheart.
post #679 of 757
Quote:
Originally Posted by SherazNJ View Post

So what's the grand secret of IMAX great sound????
Huge dynamics for spectacular impact. Even their surrounds are a pair of giant corner-loaded horns, powered by massive amplification.
Quote:
Originally Posted by SherazNJ View Post

Also do any of you have same speakers for all around (front side and back)?
Sure, not difficult to do with affordable bookshelf speakers. Helps sounds stay consistent as they pan from the front soundstage to the surround field. Even more helpful for a movie like the recent hit 'Gravity', which has lots of dialogue mixed into the surround channels.
post #680 of 757
Quote:
Originally Posted by braveheart123 View Post

Distance doesn't matter; placement does. As long as your surrounds are level matched with the rest of the speakers; it's all good.
Distance does matter. The Inverse Square Law dictates that sound intensity drops 6 dB per doubling of distance, (spherical, free air.)



https://www.osha.gov/dts/osta/otm/noise/health_effects/physics.html

In-room, the drop will be less due to room reinforcement, but there will be a drop nonetheless, likely more in the range of 3 dB/doubling of distance. In Sheraz's case, his surrounds are quite small and less capable than his mains. The further away they are, the higher the trim setting they need and the less headroom they have. So, in his case, distance does matter.

Sheraz, your idea to move your rear surrounds forward to a ceiling position behind the seating is a good one. Then be sure you rerun Audyssey to ensure you get the surrounds re-level-matched and the speaker Distance settings correct.

Craig
Edited by craig john - 11/24/13 at 2:18pm
post #681 of 757
Thread Starter 
Quote:
Originally Posted by craig john View Post

Distance does matter. The Inverse Square Law dictates that sound intensity drops 6 dB per doubling of distance, (spherical, free air.)



https://www.osha.gov/dts/osta/otm/noise/health_effects/physics.html

In-room, the drop will be less due to room reinforcement, but there will be a drop nonetheless, likely more in the range of 3 dB/doubling of distance. In Sheraz's case, his surrounds are quite small and less capable than his mains. The further away they are, the higher the trim setting they need and the less headroom they have. So, in his case, distance does matter.

Sheraz, your idea to move your rear surrounds forward to a ceiling position behind the seating is a good one. Then be sure you rerun Audyssey to ensure you get the surrounds re-level-matched and the speaker Distance settings correct.

Craig

The reason I even brought this up is because I can hardly hear anything from those speakers. They are very small speakers (smallest one can get).
Would a simple mount like this one work?
http://www.amazon.com/OmniMount-10-0WC-Ceiling-Speaker-Mount/dp/B0015YU0FA/ref=sr_1_6?ie=UTF8&qid=1385398861&sr=8-6&keywords=ceiling+speaker+mount
post #682 of 757
Like I said before; surrounds do not get full range signal in DD/DTS and same goes for the dynamic range unless you are listening in all channel stereo mode. Even if you are way up on the surround trim levels in a DD/DTS application; it will make little to no difference.

However, the ambient sound effects in surrounds do bring out the sense of depth in your sound stage making it extend beyond its physical boundaries. I normally run my surrounds a dB lower than the rest of the speakers.

What is the sensitivity of your surrounds?
post #683 of 757
Thread Starter 
Quote:
What is the sensitivity of your surrounds?

How do I find that? Also its not the surround but surround back (rear) speakers that I wanted/want to move. These are very basic and very small definitive speakers.
post #684 of 757
what's their model number?
post #685 of 757
Thread Starter 
Speaker doesn't have model number on it and I bought them years ago but based on its dimention, I'm very sure its this one.

Brand NameDefinitive Technology
Color NameBlack
Item Display Height8.38 inches
Depth5 inches
Driver Configuration1x 1" aluminum dome tweeter; 1x 4-1/2" bass/midrange drivers; 1x 4-1/2" pressure coupled bass radiator
Frequency Response Curve57 Hz - 30 kHz
Audio Sensitivity89 dB
Impedance8 ohm
Speaker Driver Material TypePolypropylene
Maximum Speaker Depth (inches)5 inches
RMS Power Range - Amplifiers150 watts
Edited by SherazNJ - 11/25/13 at 1:18pm
post #686 of 757
Quote:
Originally Posted by braveheart123 View Post

Like I said before; surrounds do not get full range signal in DD/DTS and same goes for the dynamic range unless you are listening in all channel stereo mode....

http://pacificav.com/library/Dolby%2051%20productions%20guidelines.pdf
Quote:
5.1-channel audio typically consists of five discrete, full range main channels (Left,
Center, Right, Left Surround, and Right Surround) plus an optional band-limited Low
Frequency Effects (LFE) channel for added bass (the .1). Dolby Digital bitstreams
deliver full frequency bandwidth main channels, from 3 Hz to 20 kHz, and a limited
frequency bandwidth LFE channel, from 3 Hz to 120 Hz. Current Dolby Digital
encoders accept word lengths of 16, 18, or 20 bits at sampling rates of 32, 44.1, or
48 kHz. The Dolby Digital algorithm provides 24-bit resolution, and future versions
may extend sampling rates to 96 kHz

Dolby's own literature states that the surround channels in Dolby Digital are "full range." All 5 channels are exactly the same in terms of frequency range and dynamic range. They can get content from 3 Hz to 20 kHz. The older "matrix" surround format, Pro Logic, had a limited range of 100 Hz to 7 kHz, and it was a "mono" surround track. It was purely an ambiance enhancement channel. With DD, the surround information became "discreet" and sound mixers could record full range sound effects in those channels. Those surround effects became much more than "ambiance enhancement." These discreet sounds were often meant to be localizable, and sound engineers used the localization to create "pans" from rear to front and from right rear to left rear and so forth. There is *absolutely* full range content in the DD surround channels.

Nonetheless, Sheraz is talking about the REAR channels in his system. He has a receiver and BluRay player capable of utilizing the lossless codecs, Dolby TrueHD and DTS- Master Audio. Those codecs also use "full range" surround channels, even in the rear channels. So, your statement that the surrounds get limited frequency range and dynamic range is incorrect.

Quote:
Originally Posted by braveheart123 View Post

Even if you are way up on the surround trim levels in a DD/DTS application; it will make little to no difference.

However, the ambient sound effects in surrounds do bring out the sense of depth in your sound stage making it extend beyond its physical boundaries. I normally run my surrounds a dB lower than the rest of the speakers.

What is the sensitivity of your surrounds?

His rear surrounds are 14 feet behind his listening position. They're tiny, with 4.5" drivers. No matter what their sensitivity is, there is absolutely no question that they will work better if they are closer to his LP. They'll still need significant help from the Bass Management system, with crossovers set in the 150 Hz range or so. But, if Sheraz wants to actually HEAR his rear surrounds as discreet sound sources, they need to be moved closer to his LP. Otherwise, their output will just be lost in the abyss of the rear of his room.

Craig
post #687 of 757
I agree with Craig - just make sure you leave the rears a bit behind your MLP. You don't want them directly overhead, they need to be least a couple feet back to get the benefit of rear surrounds.
post #688 of 757
Thread Starter 
Quote:
Originally Posted by Alan P View Post

I agree with Craig - just make sure you leave the rears a bit behind your MLP. You don't want them directly overhead, they need to be least a couple feet back to get the benefit of rear surrounds.

If I"m going to move them, I might as well upgrade to better rear :-). My rear are relatively small as compared to even surround. I'm using Definitive Technology StudioMonitor 350 Speakers as surround speakers. Here is the specs on them

Pair of high-performance, magnetically shielded full-range bookshelf speakers
Equipped with one 5.25-inch cast-basket polymer coned bass/midrange driver and 1-inch pure aluminum dome tweeter
Frequency response: 26Hz - 30kHz
Equipped with 8-inch pressure-driven subwoofer
High quality finish in gloss black

I was thinking to move them as rear speakers and get klipsch RS-42 speakers as surround. Here is the specs on these speakers
FREQUENCY RESPONSE: 62Hz-24KHz ± 3dB
SENSITIVITY: 93dB @ 2.83V / 1m
POWER HANDLING: 75W RMS / 300W Peak
NOMINAL IMPEDANCE: 8 Ohms compatible
LOW FREQUENCY DRIVER: Dual 4" (10.2cm) Cerametallic cone woofers
HIGH FREQUENCY CROSSOVER: 1700Hz
ENCLOSURE TYPE: Bass-reflex via dual side-firing ports
INPUTS: Single binding posts
HEIGHT: 10" (25.4cm)
WIDTH: 12.5" (31.7cm)
DEPTH: 7.1" (18cm)
WEIGHT: 11.9lbs (5.4kg)
MOUNTING: Keyhole bracket and dual 1/4"-20 threaded inserts
FINISH: Matte Black vinyl
BUILT FROM: 2010

What do you guys think?
post #689 of 757
Your rear surrounds being 14 ft behind your MLP, I'd go with RS-52 II. They have better sensitivity 95dB @ 1w/1m. Um using them as side surrounds in my set up. You won't need relocate them, as they are terribly efficient.
post #690 of 757
Thread Starter 
Quote:
Originally Posted by braveheart123 View Post

Your rear surrounds being 14 ft behind your MLP, I'd go with RS-52 II. They have better sensitivity 95dB @ 1w/1m. Um using them as side surrounds in my set up. You won't need relocate them, as they are terribly efficient.

But why would I use surround speakers in rear? These surround are bi-polar speakers and they are meant to be used as surround (as the name suggests). Therefore, I was thinking of using them as surround speakers and move my current surround as rear.
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