Use Second HDMI Out Instead of Purchasing an External Amp

[vvt72277]

Hi,

I am new to this game (two months in) and absolutely loving it! I never knew the experience I was missing without the surround sound going and simply listening to the speakers built-in inside my TV (LOL). I can definitely say it with confidence - I ONCE WAS BLIND BUT NOW I SEE!

I own a Yamaha RX-A830 A/V Receiver (7.2) and it has pre-outs built-in to attach an external amplifier if desired. Ideally, one (me) would purchase an external amp and attach it to the A/V receiver. But if I went this route I would most definitely want a very powerful 7-channel amp and this can get expensive.

But, then an idea occurred to me. I could potentially attach another A/V receiver to the 2nd HDMI out (clone of first HDMI out). I was just wondering people's thoughts on using this route. And I wanted to get feedback regarding the advantages and disadvantages of doing it this way.

This question is actually fairly involved. In certain instances I would want to bi-amp (front) and others I would want to add speakers (center and surround side and surround back). I want to hear from the experts about what happens to the audio signal when I bi-amp or not using the 2nd HDMI or ext amp route.

Further, I would like to hear about any suggestions for a quality 7-channel external HT amp which would be a good alternative. Can someone recommend a few choices? Cost would ultimately be a concern as I don't want to overspend (ideally).

Lastly, but related, I would want to hear thoughts on the power consumption (electric bill) of going either way, i.e. external amp or 2nd A/V receiver.

At this point, I'm investigating and wanting to noodle a little more on my options/choices.

Thank you in advance for your help and suggestions!

 

[Adam]

Welcome to the forum!

What speakers are you using?

I've used external amps. In my case, they were heavy, took up space, and provided no sonic improvement at my listening levels. So, question number one is: why are you considering an external amp?

Your proposed approach of using the HDMI output to run to another receiver is an interesting one, but:
(1) You'll have to check something to see if it's even possible. On most receivers, you can either have the receiver output audio from the speakers or through the HDMI output, but not both. However, based on the menu options listed on page 94 of the A830 manual, you might be able to output audio from both.
(2) Even if it is possible, you're going to run into the next issue - volume control. The pre-amp outputs on receivers are variable, meaning that the signal strength sent to an amp is adjusted by the volume control on the receiver. That's a good thing. With the HDMI output, the signal strength will not be controlled by the volume control on the receiver. The ramification is that you'd have to adjust the volume separately on both receivers and try to get them to match and blend together - it's doable, but almost surely a pain.

You can connect an external receiver using the pre-amp outputs, and the number of channels that you can connect with depend on if the second receiver has multi-channel analog inputs or not. At bare minimum, you could connect two channels because any receiver should at least have one set of analog audio inputs.

As for bi-amping, I've never done it, but I've read a number of differing opinions. I'm of the belief that it won't do you much good. You can, however, try it yourself because the A830 support bi-amping the front speakers.

 

[Swerd]

Welcome to AH. It's always good to hear how much new HT owners like you enjoy their new sound systems.

You ask a lot of questions, but I have to ask why do you want an external amp?

Your Yamaha receiver, at 100 wpc when 2 channels are driven, is probably adequately powered for most speakers driven at reasonable levels, but you didn't mention what speakers you have. Also, are you running a powered sub woofer? Diverting bass that way relieves the receiver's amps from the job of running the power consuming bass.

If your main left & right speakers really must have more power, you can accomplish that by adding an external 2-channel amp to drive them, while using the receiver to drive the remaining speakers. That would be less expensive than a 7-channel amp.

Experts agree that bi-amping is of little or no benefit. Don't waste your time or money. We have often gotten questions about this because most AV receiver manufacturers talk about bi-amping in their manuals. They do their customers a great disservice by that. The size of the power supply transformer in any amp or receiver is what limits power output. If you assign unused pre-amp out puts to bi-amp your front speakers, you are still limited by the same power supply transformer in your receiver. Only if you add an external amp, with its own power supply transformer, do you add additional ability to put out power.

I really don't understand your idea of running two receivers at once. I certainly have not tried that, and I can't imagine how it might or might not work well. Are you considering two receivers as an alternative to an external amp as a way to obtain greater power?

 

[vvt72277]

Adam and Swerd, thank you so much for your responses!!!!

ADAM: "What speakers are you using?" SWERD: "...but you didn't mention what speakers you have"

Front: Polk TSx 440t (x2)
Center: Polk TSx 250c
Surr Side: Polk TSx 220b (x2)
Surr Back: Polk TSx 220b (x2)
Subwoofer: Acoustic Audio HD-SUB10 (will probably add a Polk PSW505 to complete the 7.2)


ADAM: "You can, however, try it yourself because the A830 support bi-amping the front speakers."
SWERD: "Are you considering two receivers as an alternative to an external amp as a way to obtain greater power?"

Well, if you are not laughing already, I am sure my answers will make you laugh now.

The A830 allows bi-amping the fronts, but I believe at the cost of having no rear surround speakers (I want 4 surrounds). Although, I am now against bi-amping from the feedback that you two have provided. Do you know a way to bi-amp with the A830 and not sacrifice (turn off) the rear surrounds that I am not aware of? I am currently running the 'BASIC' profile in the 'Amp Assign' setup for the A830. There is a '5-Channel Bi-Amp' option. It makes the rears to have the signal feeding the fronts.

(Ready to laugh) Further there is a desire to add more speakers, a little vertical sound (Polk TSx 110b or 220b), and a better signal to the fronts (or any speaker that are bi-amp capable). The initial thought was why leave quality on the table, but from your feedback I have re-considered the whole bi-amping concept. Further, as for the desire for more speakers (LMAO), I did not want to use a speaker selector, but rather an amp. My system is overkill, but I may want add speakers in the future and not toss out the system I am in love with (I saw a really good deal on the Polk TSx 550t [floor models]; it tempted me).

Again, I was just examining my options and then would make an informed decision based on cost, power consumption, and of course sound quality itself. My system is already overkill and it sounds like I will just be seriously wasting money. I still want that second sub, so I'll just focus there. And as a newbie, I have more questions that I need answered and would render your time better spent. Apologies.

Thanks again for your feedback and suggestions! If you know a trick with A830 bi-amping plus additional rear sound (question I posed above), please share!

 

[Adam]

Always happy to help if I can.

Do you know a way to bi-amp with the A830 and not sacrifice (turn off) the rear surrounds that I am not aware of?

I don't believe that is possible. The best that I can tell, the A830 only has seven channels of amplification...so to bi-amp the fronts, it must turn off the signal to two other channels. Also, the way that it devotes two channels to anything but normal 7.1 surround is to turn the surround back channels off (from what I see in the manual, including a second zone and presence speakers). The only way to bi-amp the fronts and keep 7.1 surround is to add external amplification.

 

[Swerd]

No need to apologize, your questions are good, and your enthusiasm shows . You've obviously read your owners manual, and I wouldn't laugh at anyone who has done that and is curious.

Do you know a way to bi-amp with the A830 and not sacrifice (turn off) the rear surrounds that I am not aware of? I am currently running the 'BASIC' profile in the 'Amp Assign' setup for the A830. There is a '5-Channel Bi-Amp' option. It makes the rears to have the signal feeding the fronts.

Other than adding an external amp, I don't know of any way other than what you described.

Try bi-amping for yourself. It will cost you very little (do not buy expensive speaker wire), and you can always return it to the way you had it before. I think you'll find it's very hard to tell if there is any audible difference, much less a real improvement.

Further there is a desire to add more speakers, a little vertical sound (Polk TSx 110b or 220b), and a better signal to the fronts (or any speaker that are bi-amp capable). The initial thought was why leave quality on the table, but from your feedback I have re-considered the whole bi-amping concept. Further, as for the desire for more speakers (LMAO), I did not want to use a speaker selector, but rather an amp. My system is overkill, but I may want add speakers in the future and not toss out the system I am in love with (I saw a really good deal on the Polk TSx 550t [floor models]; it tempted me).

You've had your system about 2 months, and a good part of that was probably spent learning how to set it up and use it. Have you made sure you've balanced the sound among those 7 channels and adjusted the sound arrival times to fit your room furniture and speaker layout? Your receiver should have some type of auto setup routine to do that. As an alternative, you can use a hand-held SPL meter and the manual set-up method in your receiver. I found getting these right in my older 5 channel system made a big difference in the overall sound quality of the system. Doing it by ear is not possible for most people.

Before spending more money, I'd spend some time with what you now have. Get a good idea of what it's capable of doing. Different movies will have different types of audio in them, and there's only one way to hear that variety.

For most movies, and nearly all music, the most important channels and speakers are the front 3. The rear channels, in movies, are rarely as important, and in music, not at all important (unless it was originally recorded as multi channel music).

I understand that you already have the speakers for 7 channels (so why not use them?) but I don't think more audio channels is the path to improved sound. Although there are a few movies with more than 5.1 audio channels, most movies are originally done with 5 discreet audio channels. Those 2 additional rear channels are usually produced by synthesizing a signal for them from the existing audio channels.

A lot depends on the size of your room. I have my system in a normal sized family room. Others who have a theater room with two or more rows of seats find the additional rear speakers make a difference.

I've never tried "vertical height" speakers, but unless you have a room with a very high ceiling, or a theater room with a sloped floor and a flat ceiling, I don't believe adding that will make an audible difference. And as you point out, installing that will be complicated and may require a different receiver.

 

[vvt72277]

Thanks, Swerd!!!! I have read the manuals, several forum entries, and all over (Dolby, Polk, and list goes on)!!! Obviously, buying the same series for the speakers didn't happen by accident. And if I didn't read/research those, I'd be the idiot with Polk fronts and a Klipsch center channel (sorry if that offends anybody but it's definitely not my intent).

Enthusiasm is a big understatement. My very first HT system I purchased on Aug 19th - a refurbished Yamaha YHT-497. I thought, why spend the money on your first system? (learn about it and purchase something you'll really like). I got the HD-SUB10 a week and a half later because I thought the 100w (RMS of 45w) subwoofer was inadequate for my bass preferences. I couldn't tell whether the sub was distorting/clipping during sustained explosions in movies. On Sept 7th I bought the A830 and the TSx speakers at the same time (woo-hoo)! Sold the first system to my old neighbor (who BTW loves it and at that price you can't find a better HT in a box for what you are getting). THIS IS MY FAVORITE TOY SINCE MY XBOX (original, not the Xbox 360)!!! LOL!!! It escalated quick and I feel no regrets!!! I can't wait to watch movies and I am huge movie buff! I feel stupid for not doing this sooner.

SWERD: "Have you made sure you've balanced the sound among those 7 channels and adjusted the sound arrival times to fit your room furniture and speaker layout? Your receiver should have some type of auto setup routine to do that. As an alternative, you can use a hand-held SPL meter and the manual set-up method in your receiver. I found getting these right in my older 5 channel system made a big difference in the overall sound quality of the system. Doing it by ear is not possible for most people."

I used the YPAO on both systems to calibrate as a starting point and adjusted thereafter manually. I understand the 'distance' is for syncing the sound to the main listening position and I believe the 'level' is self explanatory. And 'large' vs 'small' to decide whether the crossover is used to pass LFE to the sub. BTW, I am crossing over at 80Hz (although YPAO wanted 120Hz) and I have the only the 440t fronts set to large. I don't really touch much else (no EQ adjustments) and use 1 to 3 different DSPs depending on TV, sports, or movies. And the rare times I play music, I sometimes use the '7 Channel Stereo' setting. Sorry but I (my A.D.D.) can't help myself from adding something else....when I hear/speak the words "7 Channel Stereo", the image and sounds that run through my head are the opening 2 mins of Top Gun (shows you my age) because that opening score is so memorable and amazing....and the 7 channels really allow you to be immersed in the music and the nostalgia. Lastly, I have the Extended Surround setting to "Dolby Pro Logic IIx Movie" because I read that feeds the most sound to the rears (???) based on its blending/matrixing algorithm. There are only three choices ("PL IIx Music" and EX/ES") and I still don't follow what 'Off' and 'Auto' exactly do. This I can address as a separate thread.

I will have to research what a hand-held SPL meter is and how to get one (cheaply). Sounds like I will gain from NOT attempting to do it by ear. Can/will you a recommend a quality SPL meter that is reasonably priced?

I do have more questions (very, very basic....believe me) and I will put them in as separate threads.