Yamaha Receiver Question - Underpowering speakers?

[Halon451]

I am growing a little frustrated with my setup and for as much as I think I know about Home Theater setups, I am going to concede this one to the wisdom and knowledge of the true audiophiles here in this forum.

Here is my setup: (Keep in mind that I am still in the process of upgrading the front speakers)
-Yamaha V361 500 watt Receiver (5.1)
-Center Channel: JBL N-Center Two-way speaker
-Front L/R Mains: Pioneer S-H351F-K (They were a budget purchase years ago - I lived in an apartment until recently, so they were fine for that)
-Rears: JBL Venue Balcony
-Sub: Sony SA-W3000 12" front firing (rear port)
-Sub x-over setting: Full range
-RX x-over setting: Right now at 160Hz, but have tried all settings - this still delivers the best sound so far
-Speaker settings: Levels adjusted per SPL meter at optimal listening position; front L/R speakers set to "Large" in RX - all others set to "Small"
-Matrix decoder for simulated surround set to Pro Logic II (Movie) - DD or DTS when watching DVD's or HD Channels.


Instead of straight mounting the rears on the wall as prescribed, I engineered a swivel system using hinges (for my wife's sake because they're pretty large for the size room), that allows them to be pushed back flat against the wall unless we're actually watching a movie - then I bring them out so they deliver sound from either side as they are meant to do. But I don't want to get off track..

My real question is - After hours of tweaking, calibrating levels and adjusting crossover settings; I am still not getting the warm, rich sound that I expected from the JBL's. I expected the center speaker to really be the highlight of this budget system and it's sounding a little muddy and "boxy" (I don't know how else to describe the sound).

I understand the implications of under-powering speakers, and I fear that my budget purchase of this Yamaha receiver may be the culprit. Let's just say that I'm a little disappointed that the dialog sounds like it's being delivered from inside a tin can at times (Understandably, my HDTV cable box is connected to the RX via optical and incoming cable may present less-than-stellar audio quality to begin with, but still - I got a bit of the same effect while watching DVD's - via digital coax connection to the RX.

Am I simply underpowering these speakers? Am I overthinking this too much? My instinct tells me so, but I would like to hear what the true pros have to say on the matter.

Many thanks in advance. Sorry for the extremely long post...

 

[annunaki]

Typically a speaker will sound bad for a few different reasons.

1) It is simply a ill executed design and has many panel resonances as well as poor implementation in crossover design or poor mating of driver and tweeter. It just is not a good sounding speaker to begin with and you are realizing it now after it being in the home for awhile.

2) Your center channel is out of phase with the rest of your system. Check to be sure the polarity on all the speakers is correct + to + and - to - from receiver to speaker. These are simple mistakes that can and do happen to everyone.

3) There is a problem with the speaker. Bad tweeter, bad component in the crossover (not the most likely).

Underpowering a speaker will not cause this type of sound. It simply will not get real loud and/or will sound very compressed at high levels due to the amplifier beginning to clip.

How is the center mounted or located? Is it pushed back in a cabinet? Make sure the front of the speaker is out flush with the top of your television, shelf or cabinet it is located in or on.

 

[Halon451]

I appreciate the response:

I guess I figured the JBL line (for the price) would have added a bit more quality for the buck than my previous old HTIB speakers that I was replacing... hmmm. Perhaps I overestimated the line.

I have double-checked the polarity - I am using Belden 16 ga. speaker cable, which is plenum rated (it's leftover from my old job as an A/V tech), and it is twisted insulated (red/black) inner conductors inside an outer jacket, so it's pretty idiot proof as far as getting the polarity correct. Note that I don't claim to NOT be an idiot at times, so I did double-check!

The speaker looks a little funky perched atop the entertainment center, but it is not nestled inside a cabinet, as much as my wife would like me to do on account of it's size (I try to explain to her the science involved and why it would sound bad if I put it where she wanted me to), and I have tried plugging the rear ports and have left them open - minimal results in sound quality.

 

[fmw]

I understand the implications of under-powering speakers, and I fear that my budget purchase of this Yamaha receiver may be the culprit. Let's just say that I'm a little disappointed that the dialog sounds like it's being delivered from inside a tin can at times (Understandably, my HDTV cable box is connected to the RX via optical and incoming cable may present less-than-stellar audio quality to begin with, but still - I got a bit of the same effect while watching DVD's - via digital coax connection to the RX.

Am I simply underpowering these speakers? Am I overthinking this too much? My instinct tells me so, but I would like to hear what the true pros have to say on the matter.
...

Very unlikely. Since you have a powered sub, that unit provides most of the power needed to drive the sound. The mids and highs don't require nearly as much power. It is actually pretty difficult to under-power the mids and highs with modern equipment. Whatever sound comes from your center speaker results from the original recording, the speaker itself and the room in which it operates. Everything else is fairly trivial in comparison.

 

[ParadigmDawg]

I appreciate the response:

I guess I figured the JBL line (for the price) would have added a bit more quality for the buck than my previous old HTIB speakers that I was replacing... hmmm. Perhaps I overestimated the line.

I have double-checked the polarity - I am using Belden 16 ga. speaker cable, which is plenum rated (it's leftover from my old job as an A/V tech), and it is twisted insulated (red/black) inner conductors inside an outer jacket, so it's pretty idiot proof as far as getting the polarity correct. Note that I don't claim to NOT be an idiot at times, so I did double-check!

The speaker looks a little funky perched atop the entertainment center, but it is not nestled inside a cabinet, as much as my wife would like me to do on account of it's size (I try to explain to her the science involved and why it would sound bad if I put it where she wanted me to), and I have tried plugging the rear ports and have left them open - minimal results in sound quality.

Does your Yammy have the center channel EQ? When I have the EQ on in mine the center isnt all that clear, when I turn it off it is very clear.

 

[GlocksRock]

you mean your yamaha receiver has a separate eq just for the center channel? That is interesting... I wish mine had something like that.

 

[ParadigmDawg]

you mean your yamaha receiver has a separate eq just for the center channel? That is interesting... I wish mine had something like that.

Yes, you can choose off, auto EQ or EQ it your self with 5 fq sliders. It sounds best off.

 

[GlocksRock]

I have those options too, I just don't think I have the option to eq just the center... heck maybe I do and just don't know it. It doesn't really matter though, I'm selling my RX-V1600 and getting the RX-V1800 so I can pass 1080p and get 7.1 PCM via HDMI, plus the other things it offers over my current yammy.

 

[mtrycrafts]

-Sub x-over setting: Full range
-RX x-over setting: Right now at 160Hz, but have tried all settings - this still delivers the best sound so far
-Speaker settings: Levels adjusted per SPL meter at optimal listening position; front L/R speakers set to "Large" in RX - all others set to "Small"

Try to experiment setting all you speakers to small, make sure LFE is YES and lower the crossover to 100Hz or preferably lower, closer to 80Hz. See what happens and let us know.

 

[Halon451]

Does your Yammy have the center channel EQ? When I have the EQ on in mine the center isnt all that clear, when I turn it off it is very clear.

It does have the center EQ, and I've toyed around with the 5 different frequency settings, but it doesn't appear to have a "toggle" function that will allow you to turn it off completely. So here's what I did instead: I zeroed out all the frequencies and it actually did make improvements to the sound, at least initially. I'll have to check it against a few different audio sources to see if it really did the trick.

Excellent tip - I didn't even think of that. I got too caught up in using the EQ for proper timbre matching with that old set of Pioneers. It's like trying to make a Pinto sound similar to a Ford Mustang.

 

[Halon451]

Try to experiment setting all you speakers to small, make sure LFE is YES and lower the crossover to 100Hz or preferably lower, closer to 80Hz. See what happens and let us know.

Tried it - and unfortunately it weakened the overall sonic effect of my system. It seems like it audibly polarized the frequency spectrum a little too much and left gaps somewhere the in 100-200Hz range. I do have one of those Home Theater tune-up DVD's - it has a low frequency sweep for checking such things, but I haven't had the time to put it in and do a thorough test.

This is where I suspect that perhaps my amp is not providing enough power - as someone mentioned above it takes more power to drive the lower frequencies, therefore when I turn to X-over down to try and match the labeled frequency response of the JBL's (around 75Hz for the Center) - even set at 100Hz to try and overlap the range a bit, it seems like something is lost in the mix. It's as if the JBL isn't getting enough kick from the amp to deliver the lower frequencies it is designed to do.

Would this be a correct assesment?

 

[mtrycrafts]

Tried it - and unfortunately it weakened the overall sonic effect of my system. It seems like it audibly polarized the frequency spectrum a little too much and left gaps somewhere the in 100-200Hz range. I do have one of those Home Theater tune-up DVD's - it has a low frequency sweep for checking such things, but I haven't had the time to put it in and do a thorough test.

This is where I suspect that perhaps my amp is not providing enough power - as someone mentioned above it takes more power to drive the lower frequencies, therefore when I turn to X-over down to try and match the labeled frequency response of the JBL's (around 75Hz for the Center) - even set at 100Hz to try and overlap the range a bit, it seems like something is lost in the mix. It's as if the JBL isn't getting enough kick from the amp to deliver the lower frequencies it is designed to do.

Would this be a correct assesment?

I don't see this as an amp problem until you are driving your speakers to a level near the amp power limit which will give you a very loud low band to begin with.
I see this as a speaker, sub, room and setup issue. Perhaps that sweep will show your problems? At normal levels, that sweep test should give you an 85 dB spl easily on all the frequencies and the amp would be almost idling. If that JBL has a lower spec of 75Hz, not sure if that is a -3dB point or a -6dB point. That is one reason to try the crossover at 80Hz to 100Hz. Beyond that, your sub will reproduce frequencies that will throw off the direction of those frequencies and will localize to the sub.
Something is just not right someplace and it isn't your amp as of now.

 

[Davemcc]

If you have a phase switch on the sub, be sure that it is at 0 and not 180. If it is out of phase, it will interfere with the lower frequencies of your other speakers regardless of where the x-over is set.

Also, be sure that the x-over on the back of the sub is set to the highest possible setting, effectively disabling it. Then you can just use the x-over on the receiver for that function. If you try to use both x-overs at or near the same frequency, you may experience a cascading slope that might cause a hole where the frequencies are intended to overlap.

 

[Halon451]

I really appreciate the advice fellas. I'm going to try the sweep test tomorrow when my wife is busy doing other things and won't be bothered by it - as for now, I do have the sub x-over setting at max, and the phase switch has been in the '0' position since I purchased it.

As far as I know, the lower frequency rating of the JBL is the -3dB point. Nevertheless, something ain't right for sure - when I set the RX crossover to 80 or 100 Hz the system is lacking more than when I up it to about 160 Hz (still so far the best sounding setting I've used. It just contradicts the theory of how to mate your speakers with the sub. There's something I'm not getting here..

 

[PENG]

As far as I know, the lower frequency rating of the JBL is the -3dB point. Nevertheless, something ain't right for sure - when I set the RX crossover to 80 or 100 Hz the system is lacking more than when I up it to about 160 Hz (still so far the best sounding setting I've used. It just contradicts the theory of how to mate your speakers with the sub. There's something I'm not getting here..

As mtrycrafts said, you really should set your L/C/R speakers to small. If you still have them set to Large, then by upping the Rx crossover to 160 Hz affects only the center and surround channels that you said were set to "small". Again, with the mains set to "large" you can't really "mate your speakers with the sub" (just quoting yours) because the receiver's crossover settings would have no effect on channels that are set to "large".

Please try setting the mains to "small" again, then play with the other settings such as equalizers, speaker output levels, subwoofer crossover, subwoofer phase settings etc. I would also suggest you first reset all parameters in your RX-V361 to initial settings before doing any more tweaking.

 

[Halon451]

Alright guys - here's the latest:

I set all parameters to the initial factory settings, set the L/C/R and surround speakers all to "small", left the sub crossover at max setting, turned the RX crossover setting to 100Hz, and ensured the Center EQ was zeroed out.

Then I sat down to perform the audio tests on the HT tune up DVD. After setting the correct levels for all speakers, the one I really wanted to get to was the frequency sweep test. Note that I used the SPL meter for this test as well, which may not have given a fast enough response time to ensure it fully represented any dips in output level across the sweep, but a test on 'C' weighted and both in fast and slow, I saw no real dives in SPL, prior to the sub reaching its lower frequency limit.

I feel rather confident that I've tweaked the system to the best possible settings at this point - however the Center speaker still tends to sound like poo, most notably during dialog (voice) intervals. I can detect no undesirable sounds for effects and other types of audio output from the center, but when someone speaks, it still tends to sound hollow and weak.

Do you think it's simply my JBL N-Center that's to blame at this point? Anyone have any other suggestions that may correct this problem?

Thanks very much again - great help!

 

[mtrycrafts]

Alright guys - here's the latest:

I set all parameters to the initial factory settings, set the L/C/R and surround speakers all to "small", left the sub crossover at max setting, turned the RX crossover setting to 100Hz, and ensured the Center EQ was zeroed out.

Then I sat down to perform the audio tests on the HT tune up DVD. After setting the correct levels for all speakers, the one I really wanted to get to was the frequency sweep test. Note that I used the SPL meter for this test as well, which may not have given a fast enough response time to ensure it fully represented any dips in output level across the sweep, but a test on 'C' weighted and both in fast and slow, I saw no real dives in SPL, prior to the sub reaching its lower frequency limit.

I feel rather confident that I've tweaked the system to the best possible settings at this point - however the Center speaker still tends to sound like poo, most notably during dialog (voice) intervals. I can detect no undesirable sounds for effects and other types of audio output from the center, but when someone speaks, it still tends to sound hollow and weak.

Do you think it's simply my JBL N-Center that's to blame at this point? Anyone have any other suggestions that may correct this problem?

Thanks very much again - great help!

I have one more suggestion for you to test the center dialogue
Find a specific source, CD/DVD that is a no brainer that the dialogue is not what it should be then swap the center speaker with the left or right and see how much the dialogue has changed, one way or the other.
If it has changed dramatically to your liking, get another center speaker Many times, however, the center is compromised because of space and location.

 

[Halon451]

(Imagine me slapping my forehead) Of course! I swear sometimes everyone tends to over-think things when it gets down to the nitty gritty like this.

I'll do this and post the results. Many thanks!

 

[mtrycrafts]

(Imagine me slapping my forehead) Of course! I swear sometimes everyone tends to over-think things when it gets down to the nitty gritty like this.

I'll do this and post the results. Many thanks!

Well, it just dawned on me too and posted.

 

[Halon451]

Well I suppose this topic has migrated away from being an amplifier question to one concerning speakers and hence, probably belongs in the suitable location in this forum, but switching the speakers did highlight one obvious fact: that my room acoustics leave an awful lot to be desired.

I did one better - after switching the center with the left front speaker, I disconnected it and hooked it up to another regular stereo system of known good quality, and it sounded terrific. I then made an extra long speaker cable, hooked it back up to my HT setup and experiemented by moving it around several locations in my room.

What I found was that there seems to be a resonant frequency issue somewhere in the 300Hz range (I'm estimating) where I normally place the center channel - and I can't figure out how to minimize the effect. My room layout really only leaves one configuration option for a standard HT setup, so perhaps some good acoustic damping material would do the trick - I don't know.

Here's the room setup: to give you an idea...