Some questions regarding my new HT system

[ausastronomer]

Hi All,

I am new to this forum and a bit of a novice with home theatre/surround sound. I can appreciate that in hindsight I should have found this forum and asked the questions 1st but that didn't happen and whats done is done. I have just put together my 1st AV system (5.1) which consists of the following components:-

Sherwood Newcastle R-865 AV Receiver
Paradigm Reference Studio 60 Front Speakers
Paradigm Reference Studio CC-470 Centre Speaker
Electrovoice S40 mini monitors for the rears
Yamaha YST SW800 Subwoofer
Panasonic DVD CV52 DVD Player
Sony KVHR32M31 CRT Television

My room is 20 feet x 15 feet with a tiled floor but I have rugs all over the place, a lot of soft furnishings and thick curtains on all the windows so the acoustics in the room are reasonable.

All the components are new except for the DVD player which I have owned for about 2.5 years.

I have used good quality cable and interconnects throughout although nothing is bi-wired which I dont really understand much about anyway.

I am very satisfied with my setup, whilst I can appreciate thats its not "top end" it walks all over the home theater in a box packages. Also be aware that everything in Australia costs about 2.5 times what it costs in the USA, so good gear aint cheap here.

I have several questions about my setup:-

1) When I switch from 2 channel mode to 5.1 surround I notice a bit of a drop off in the volume level. Normal listening level in 2 channel mode is
say -30db whereas I need to go to -20db in 5.1 mode to get the same overall volume level. Having said that the system has plenty of headroom to play the loud sounds in 5.1 mode so its really only numbers on the dial. I can appreciate that there must be some dropoff as you have the same power supply now trying to drive 5 amplifiers when it was previously only driving 2, my question is, is the drop off level I am experiencing normal of most AV receivers at this price level?

A friend has also suggested that my DVD player could be the weak link here as it may be providing a lower input signal to the receiver in 5.1 mode compared to its input signal in 2 channel mode, any thoughts on this ?

2) A different friend (who thinks he's an expert - questionable IMO) has suggested that I bi-wire the front and center speakers, will I gain anything by this? The dealer I bought the system from said that bi-wiring and bi-amping is only beneficial in high end systems running separates and I would not notice any benefit at this level, your thoughts ? I suppose this depends on what cable I am already using ? Assume its reasonable quality and in keeping with the rest of the system. I think its Soundlink 11SWGA 99.95% OFC. The runs to the front speakers and center are also fairly short all being less than 2.5 metres.

3) The same bi-wiring friend suggested that I may benefit from using the pre-outs on the front 2 channels and running separate amplification on these. What benefit do I gain by doing this when my wife says the thing is already way too loud and asks me 2 turn the volume down?

4) Any other suggestions anyone can make that can improve the system without spending an arm and a leg would be appreciated.


Regards and Thanks in advance

[spacedeckman]

The question: Do you have your DVD player hooked up using either an optical digital or coaxial digital cable? I think the volume drop is caused by going from stereo to Pro-Logic, which would cause the drop. It isn't the amplifier as suggested. From my position half way around the world, it appears that you are hooked up using only the analog outputs of the DVD (Just as you would hook up a CD player or VCR).

The suggestion: In the short term, replace the Electrovoices with the corresponding Paradigms. It is best to have all your speakers "voice matched" or sounding the same. The least critical of the full range speakers is the surrounds, however.

Other than that, it sounds like a nice system. BTW, if you have the choice, personally, I prefer a digital coax (looks like regular RCA). Matter of fact, if you know your way around a soldering iron, build one from a piece of CAT5 wire using two "decent" quality phono plugs. I was goofing around one day with a decent "store bought" digital cable, 1/2 a fairly spiffy pair of upscale interconnects, and my homebrew CAT5. The CAT5 was noticably better. You separate the striped wires from the non-striped, strip the ends, then twist the stripes together, then the non-stripes. I've always used all the wires, but in reality you could get the same result from using only a pair or two...it would be easier.

[ausastronomer]

Thanks for your reply,

I should have mentioned a couple of other parameters:-

The rear speakers have to be ceiling mountable using brackets, thats why I chose the Electrovoice S40's, any other suggestions? The system is in a large conservatory with glass on 2 sides, covered with thick drapes, unfortunately the 2 sides where the speakers would otherwise be mounted.

I spend 50% of my time listening to audio CD's in 2 channel mode, thats why the front end is a bit stronger than the back end as I figured the rears were less critical in the equation and I had already pushed the budget to its max. I would love to be able to use the Paradigm Studio 20's or the matching Reference series di-poles (ADP-470's) but unfortunately I couldn't really afford them at this time and in addition I couldn't mount them anyway.

I have the DVD player connected using component/digital optical and the the satellite TV box is connected S-Video/digital optical.

In respect of the volume drop, your saying its caused by the extra "signal processing" involved with dolby digital or DTS as opposed to whats required in Stereo mode rather than the power output of the amplifier section itself ?

Thanks again.

[eisforelectronic]

My opinion is that if there is a substantial drop in volume when switching from 2 chnl to 5.1 chnl, then it is possible the receiver is using a single amplifier and splitting power off to each chnl. Most of the manufacturers of higher quality receivers typically provide separate (discreet) amplification for each channel.

[NickWH]

My opinion is that if there is a substantial drop in volume when switching from 2 chnl to 5.1 chnl, then it is possible the receiver is using a single amplifier and splitting power off to each chnl. Most of the manufacturers of higher quality receivers typically provide separate (discreet) amplification for each channel.

Most low-end receivers only have a single power supply for all channels of amplification. This is another cause for the drop in volume when going into surround mode. Better receivers have a power supply for the main channels and a seperate power supply(s) for the surround channels.

[ausastronomer]

My opinion is that if there is a substantial drop in volume when switching from 2 chnl to 5.1 chnl, then it is possible the receiver is using a single amplifier and splitting power off to each chnl. Most of the manufacturers of higher quality receivers typically provide separate (discreet) amplification for each channel.

Nick,

The receiver definately has discreet amplification. It also has a pretty large torroidal transformer feeding the power supply for a receiver at this level. The unit weighs 27kg which compares to similar recievers in this class like the Denon 3805, Marantz SR-7400, Pioneer VSX-55TXi, Harmon Kardon AVR-630 and the Yamaha RXV 2400 which all weigh some 5 to 10kg less than the Sherwood Receiver. So if the weight is not in the power supply they have made the chasis out of very thick steel.

Regards
John

[NickWH]

The receiver definately has discreet amplification. It also has a pretty large torroidal transformer feeding the power supply for a receiver at this level.

While this may well be true, the power specifications for this receiver are quite wimpy:

AMPLIFIER SECTION
Power output, stereo mode, 8 ohms, THD 0.05%, 20Hz-20kHz | 2 x 100W
Surround Mode, only one channel driven
Front power output, 8 ohms, 1kHz, 0.7% THD | 110W + 110W
Center power output, 8 ohms, 1kHz, 0.7% THD | 110W
Surround power output, 8 ohms, 1kHz, 0.7% THD | 110W + 110W
Surround back / ROOM2 power output, 8 ohms, 1kHz, 0.7% THD, 110W + 110W

When this receiver goes into surround mode, the power level must drop because Sherwood only rates the power for a single channel, at a single frequency, and the distortion level jumps considerably. This is not the case with the Denon, HK, Yamaha and Marantz receivers. The receiver is indeed heavy, however there is no mention of just how large that "huge torroidal transformer" is in the literature.

[anamorphic96]

I would not worry to much about those output specs. In surround mode the unit is probably about 75 watts per channel. When you look at a rated 1khz spec you should take 15 to 25% off the wattage number and you will be in the ball park of what the full bandwidth number would be. The other thing to keep in mind is that companpies like Yamaha, Denon, Marantz,Onkyo, Sony all rate there receivers into two cahnnels as well. The only companies who do the all channels driven specs are Rotel, Nad, and Harman Kardon. But if you notice, there ouput specs are much lower. There might be some other companies that do the all channels driven rating as well. But off the top of my head these three came to mind. This does not mean that the receivers cant output the power specified into the channels listed. They just cant do it with all channels driven.

The volume change you are talking about is not drastic either. Most receivers need some volume boost when switching to surround modes. All the receivers I have owned needed some. If you had to bring the volume to 0 or a positive number I might worry.

Sounds like your unit is running fine.

Cheers.

[anamorphic96]

http://www.audioholics.com/techtips/audioprinciples/amplifiers/receiverpower.php

Copy and paste this link. Its a very honest look at receiver ratings and power diffrences between models and how receivers are rated. The article is well written and comes from a former Yamaha product manager.

Cheers