Axiom Home Page Forums General Discussion Stereo Yamaha HTR 5740 (6.1) for stereo in multiple rooms

Sorry in advance for a long-winded post. For my "secondary" system I have had a Yamaha 5740 with M22s and Velodyne CHT-8 in our living room and have been very happy. The receiver is rated for "POWER RATING 1kHz @ 8 OHMS = 6 X 100 WATTS, POWER RATING - 20Hz - 20kHz @ 8 OHMS = 6 X 85 WATTS" (copied and pasted from the Yamaha website). Due to geography/ease of use we wanted to use this receiver to drive speakers in our bedroom and on the outdoor deck by the pool as well. So, Friday we had someone (been in business 10 years, done work for several colleagues over that time with good results/knowledge, etc.) come hook up/wire the system through a 4 way switcher (would be happy if someone could tell me the correct name for this device) setting up 3 zones (living room, bedroom, pool - all speakers are 8 ohm, 2 speakers per zone plus sub in living room) and leaving one of the zones unassigned/speakerless. Since that time, the receiver has had the habit of just spontaneously cutting off if it is set anywhere near a high setting (it goes from -80 to + 15 and will cut off after a while at -15 which is not really that loud). I haven't had a chance to really check it out and see that it is all wired correctly (I'm typing this at work) but before I do I thought I might get some thoughts from the very helpful people here.
My thoughts/questions include:

We bought the wrong receiver for this purpose, but based on what was availble at the time that we were shopping with Best Buy gift certificates it seemed like a reasonably good receiver for a reasonably good price that would allow for possible expandability/backup for home theater and that 85 watts would be powerful enough to take care of any of our stereo needs. True?

Because my wife insists that the components (receiver and CD player) be put in the cabinet and the CD player is currently sitting on top of the receiver, it may just be overheating and I need to rearrange things to allow for adequate cooling?

Does having 6 speakers (although this problem happens with just one room turned on also) cause this type of trouble and if so is it because the resistance is too low - like trying to drive a 4 ohm speaker? Or am I totally confused?

If is not something simple like getting the CD player off the top of the receiver what is the best solution? HK 3480 stereo receiver? Separate amp? I'm open to suggestions.

I apologize for asking for help before I have really checked out some of the simple stuff, but it is on my mind and has raised some questions in areas that I would like to better understand anyway so I figured I would just go ahead and throw it out...

Thanks in advance.

I am NOT knowledgeable about this kind of stuff. But, I DO know, if the receiver's cooling vents are on the top of the receiver, having your CD player on top of it is NOT a good idea. Add in the fact that the receiver and CD player are in an enclosed area, and you have a classic scenario for an overheating problem. For sure, I would try rearranging before I made any other move. This, of course, assumes one can lock the wife in the closet long enough to get away with said rearranging and testing.

If the Cd player is sufficiently sturdy, you can place the receiver on top of it, assuming it will fit. That doesn't resolve the enclosed space problem, but it might be the first thing to try. If the wife continues to insist the components remain inside the cabinet, and if there is a back to the enclosed area, you might consider buying a small exhaust fan (similar to the one in a computer), cutting a hole in the back and mounting the fan in the hole to pull out the overheated air, thereby keeping things cooler.

But, the first thing to do is set up the receiver in open space and run it to see if overheating is, indeed, the problem.

Rockler sells quite a few different vent covers and a powered fan like Ajax mentions. If you determine that heat really is your problem and you don't want to ditch the cabinet, this might do the trick...

http://www.rockler.com/ecom7/product_details.cfm?&sku=6572&cs=1

Foghorn,

If you run any two pairs of speakers together with your switcher, the combined 8-ohm impedances will present a 4-ohm load (or perhaps even lower, if there are impedance dips on one of the speaker pairs) and Yamahas do not like 4-ohm loads. I think it's a combination of poor cooling and the low impedances when you run more than one zone. The thermal sensor would definitely shut down the Yamaha to prevent overheating, and I suspect the Yamaha also has a current-sensing circuit with current-limiting provision. So when it senses more current flowing to the lower impedance, it limits the Yamaha's output or shuts it down.

Domestic A/V receivers are not designed to drive multiple speaker sets in this sort of application. The advice on proper ventilation is sound. It might make a difference.

Regards

Thanks to all for the input. I will definitely try to address the thermal issue when I get home tonight. If that fails and everything else checks out, what receiver would be a good solution? I have a 14 year old Denon DRA-325 (50 wpc) in the garage that I will try next, but if I have to buy one I'm thinking of going with Harman Kardon or is there a better solution? Comments? Thoughts?

There are others more knowledgable (and some of them may also even be typing right now), but...

I'm suspicious of the "switcher". It seems like there are devices out there that somehow maintain a more benign load under such circumstances (Niles audio perhaps?).

Absent that, I'd try using that Denon to power the other zones - you may be able to feed the line in of the Denon with the line out from the Yamaha if there is not a more elegant solution. I'll bet that even if you power one other zone with the Denon, you'll solve the problem. I don't think you need a big, new, expensive amp to fix this problem. But then, I'm a cheapskate.

Fog, definitely get the CD player off the top of the receiver so that it has a better chance to cool. While running two or more speakers in parallel serves to reduce the net impedance(the sum of the reciprocals of the individual speakers equals the reciprocal of the total impedance, e.g. 1/8+1/8+1/8=3/8 or 2.66 ohms), you say that it shuts off now when even one set of speakers is connected through the switching device. Despite the experience of the installer, I'd question whether the connections are correct.

Thanks for all the input. By reading the owner's manual, I was able to find that there is an impedance switch on the back of the receiver - and by switching it to the setting suggested for 6 ohm or lower speakers I can play the receiver for many hours at reasonably loud volume (-5) in all speakers. I haven't had a chance to get into the cabinet and put the receiver on top of the CD player, but I have checked the receiver and it never really feels warm, let alone hot. I think I'll take what I've got and run with it - although I have one more question for the helpful folks here:

If I change to my 1990 Denon DRA 325 50 Watt stereo receiver, I will not have the option of connecting the CD player via the optical audio (toslink? - someone help me with the terminology here) connection. How important is this?

I believe the <6ohm switch just limits current to each set of speakers to avoid tripping the protection circuit.

As for TOSlink (optical digital) and SPDIF (coaxial digital) for your CD player (you used the right term) - probably wouldn't be so bad to just use the analog outs for any stereo/2 channel application.

Bren R.

Bren,

Is that why the 2 channel stereo receivers (HK 3480, Denon DRA 685) don't have TOSlink inputs? Because (and this may start another battle around here like the cable issue) when I bought a TOSlink cable and hooked my CD player to the Yamaha 5740 the sound seemed to improve significantly from the coaxial connection...

>>If I change to my 1990 Denon DRA 325 50 Watt stereo receiver, I will not have the option of connecting the CD player via the optical audio (toslink? - someone help me with the terminology here) connection. How important is this?

My first impression is that most people with a good (well, "better than crappy") CD player tend to stay with analog signals and slightly prefer them. My "really cheap" CD changer seems to sound better with a digital coax connection than with the analog connection.

I'm starting to suspect that middling-good CD players have good analog output quality and sound great with analog connections while the cheapest of the cheap have crappy analog outputs and sound better with a digital feed.

If your receiver does not have a "pure analog / bypass all the DSP stuff" mode (aka "Stereo Direct" etc..) then I imagine a digital connection is the way to go. Stereo receivers always operate in "bypass all the DSP stuff" mode cause they normally don't HAVE a DSP

JohnK - I don't think that the formula would apply to the switcher device. It would have to be a bad switcher for it to not run some in series and some in parallel.

I have a 4 way switcher, and it runs some channels in parallel and others in a series. If all 4 are enabled, my switcher will present the same impedance as a single pair (assuming all impedances are equal). Only running 1 and 2 or 1 and 4 give 1/2 original impedance and running 1 and 3 or 2 and 4 give double the original impedance. It's not like mine was of high quality either... It's just some $35 toy I got from a local Rat Shack years ago. I'd be surprised if Forghorn's didn't do that as well...

Thanks for the info, but in some ways I am just more confused.
What is digital vs analog vs optical? To connect my CD player to my receiver I have 2 options: A single optical (TOS link) cable or a double (R and L) cable. Are those "digital" or "analog" or something else?

I don't know about the impedance calculation, but when I switched the receiver to a lower impedance setting, the situation improved dramatically. Here is a link to the "switcher" - actually "speaker selector" - I got the SDB 4.1.

http://www.russound.com/speaker_selectors.htm

It seems to work fine, but the connections are limited to 14g max and I wonder if that is enough for optimum sound (I know, here goes the cable debate again, but if I'm not mistaken, most people here recommend 12g - right?)

Also, because I want the subwoofer to be only as loud as the M22s in the living room, it is now connected through the "speaker selector" whereas before when I only had one room, I had it connected through the subwoofer "out" and it doesn't sound nearly as good no matter where I set the crossover. Any suggestions?

Thanks again.

Foghorn,

There are two types of digital connections possible between player and receiver. One is an optical connection (TOSLink), the other is a coaxial connection (SPDIF). You know what a TOSLink cable looks like. The coaxial digital cable is just a regular interconnect with RCA plugs at either end. The outputs and inputs where you plug in the "double (R and L) cable" are ANALOG, not digital.

Lets start at the CD or DVD disk itself. The information on the disk is digital (1s and 0s). Your speakers, however, are analog. So, somewhere between the disk and the speakers, the digital information must be converted into analog information.

If your player has both digital and analog outputs, then the player has DACs (Digital to Analog Converters. Actually I don't know if there is only one or if there's more, but regardless, the player has something, DAC(s), that convert the digital signal to an analog signal).

But your receiver ALSO has DAC(s) that can do the same job. If you hooked up the player to the receiver with a digital connection the the information on the disk stays in the digital domain until it gets to the receiver. If you use the analog connection between player and receiver, then the player converts the digital info into analog. In order to take advantage of the digital processing in your receiver (DD, DTS, etc.), the receiver must receive a digital signal. If you send the receiver ONLY an analog signal, all you're gonna get is stereo.

As this wire table will show you 14 gauge wire is just fine for just about everything except a cable run of over 40 feet to a 4 ohm speaker. Most of us use 12 gauge just to be on the safe side. No big deal.

Don't quite understand your subwoofer problem, but if you connect the sub to the "sub" or "LFE" output of your receiver, and properly calibrate all your speakers, your sub should be balanced with the 22s just fine.

I'm not an expert, so anybody that feels I haven't quite presented this correctly, please correct me.

>>Don't quite understand your subwoofer problem, but if you connect the sub to the "sub" or "LFE" output of your receiver, and properly calibrate all your speakers, your sub should be balanced with the 22s just fine.

I think the question here is "if I have speakers hooked up in two rooms, but the subwoofer is only in one room, how do I wire things up so the sub only runs when I am in that room ?". Sounds like Foghorn was using the sub out before but switched to using the "high level inputs" on the sub (connected to speaker outs from the amp) so the sub would only be active when the speakers in that room were active.

My understanding is that you normally get a small loss of sound quality when using high level inputs (since the signal now has gone through the amp as well and is brought down to line level with resistors) but the difference should be pretty small.

Your description of analog vs. coax digital vs. optical digital was nice, should be a stickie

Thanks John. Now I understand Foghorn's subwoffer dilemma. I still can't help him with it, but at least I understand it.

Thanks all. The subwoofer issue is as described and I have pretty much figured out that it is likely a combination of using the high level input and positioning of the speakers. Once we got the house all wired for the 3 rooms the subwoofer was placed in the bottom cabinet with stuff (boxes of board games, etc.) sharing the space leaving it only about 3" in the back and 1" on each side to breathe - so I am going to have to negotiate with my wife on this issue. The M22s don't sound nearly as good now that they are pushed back into the cabinets either. When I had all 3 speakers just sitting out "cluttering up" the (>8000 cubic feet) room the system sounded great. I wish I had never heard it like that so I wouldn't know what I am missing - of course then I would be here saying Axioms are not that great...