Optical or RCA ?

[colinB]

Now i have a descent HD telly im planning a AV system comprising of a Yamaha dsp e800 for processing duties and ps3 for source material.
It means i have to take an audio signal from the tv ( using the built in Freeview) to the Yamaha . I have the option of keeping the Yamaha under the tv and feeding the signal to the power amp which is on my hi fi rack at the side of the room, or putting the Yamaha on the hi fi rack and feeding it with a very long optical cable.
Either way there will be a distance of at least 5 meters between the tv and the hi fi rack and so im wondering what the best plan would be. A long pair of RCA cables to link the amps or a long optical cable between the tv and the amps sitting at the side of the room.
In terms of signal quality and cost which way would you go?

[Reid Malenfant]

For quality i'd go via a coaxial connection ;) However very weird earth loops can happen if that digital connection isn't galvanicly isolated & there is some kind of loop formed. I have killed the HDMI & DVI outputs on a Denon DVD2910 because there was some kind of freaky current circulation (this is how come i'm still only on 2 channel stereo for fear of messing other stuff up). You would be 100% safe with a Toslink connection though as it's totally electrically isolated :)

If going for best quality via Toslink get a glass fibre & not a polycarbonate cable :cool:

[colinB]

If i could get a glass toslink 5m for about £50 i would be happy.
I wouldnt want to pay any more than that though.

[Spectral Morn]

RCA imho


Regards D S D L

[colinB]

I like that answer. I can make RCA interconnects on a budget compared with toslinks which could be pricey.

[colinB]

Will 5m of cable degrade the signal?

[Reid Malenfant]

Not really, it just needs to be the right impedance ;) 75Ohm RG59 will do nicely :)

[colinB]

Thanks Mark. Ive heard the Van Damme cable is good , i will check the specs.

[jantheman]

Just for info...I have tried both Coax and Toslink and I have convinced myself that Toslink is better. That however is a decent glass Toslink from MG. Not because I was getting earth loops as Mark says, just because it sounds better to me. How...it just sounds smoother and less gritty/harsh or whatever you want to call it. Dont discount either from your list, try then buy if posible.

[Jac Hawk]

If you have a toslink output on yer tv colin i would go with it as you will get zero interferance from it, and to be honnest you would have to pay a fair bit for a good quality sheilded spdif (coaxial) cable, so it's not gonna be a simple choice based on price, also i would say the toslink cable is going to be much thinner and easier to hide ;)

[colinB]

Sorry i havent made it clear. The choice is not between a toslink or co axial digital.
The Yamaha links with my stereo amp with ordinary stereo interconnects and the tv will be linked to the processor with the optical.
If i keep the processor and amp together on the rack to the side of the room, about 5 m from the tv, i will have to get a long optical to connect to the tv.
If i put the processor under the tv i will have to use a short optical but link the amps, now seperated by 5m, with a long pair of stereo interconnects because everything ,including stereo sources that go into my stereo amp, go through the Yamaha.
Which way would be better?

[Stratmangler]

Long Toslink.:)

[colinB]

Thanks:)

[Alex_UK]

Long Toslink.:)

+1

[colinB]

Never bought an optical cable before , i get the idea they vary in quality more than analogue cables. Maybe Mark Grant could make me something that long.

[Reid Malenfant]

Well you have a choice, polycarbonate or glass fibre. If you care for quality then i'd definately go for a glass fibre optical cable with that kind of length, not exactly cheap though unfortunately :doh:

I'd suggest a PM to Mark Grant as i know he sells the glass fibre type & as you say, he might be able to sort you something out :)

He's certainly helped sort me a load of stuff out, top bloke! :cool:

[colinB]

Yes,Mark appears to do glass fibre.
I have never shown any interest in digital audio or home cinema before but as you can probably tell im on one at the moment:doh:
Watching kef eggs on e bay and various subs. Hope its all worth it.
Ive never heard a good system before, the ones i have heard have been all in one cinema in a box type and they have never impressed me, but im up for giving it a go.

[Reid Malenfant]

Take your time Colin, you don't want to rush this :mental: Fools rush in & all that...

:lol:

Far better to get a good feel for what it's all about so you can make properly informed decisions ;)

[colinB]

LOL yeah thanks Mark.

[Reid Malenfant]

Actually whilst preparing my dinner i was thinking about what you mentioned... I'd forget about the Kef eggs if i was you ;) These really are kind of entry level things that look very nice indeed but will soon become quite lacking in performance. The reason being is that as the drivers are so small (4" if i remember right) they do bugger all bass. Now you may well think that it doesn't matter as you'll have a sub, but it will because the small drivers might get you to 100Hz & at this high a crossover frequency you'll start noticing the position of the sub in the room whilst listening. Not only that but they'll soon run out of headroom when things get serious :eyebrows:

I know WAF factor may be involved but if i was you i'd look for a decent pair of small standmount speakers for the rear surrounds, something like Mission 780SE would be great imo as you could integrate them much easier & probably buy the things cheaper than the eggs ;)

[colinB]

I had a demo last year at sevenoaks of a B&W sub that no one bothered to set up properly, despite giving them my speakers in the morning:steam:
Anyway, i was shocked that i could tell the direction of the sub and was aware of the thing farting away in the corner. I want to avoid that at all costs.
I was only thinking of the eggs for the rears though mark, thats why ive gone for the Yamaha processor as it means i can keep my stereo fronts and carry on using them with my integrated.

[colinB]

Maybe i should concentrate on setting up a good 2.1 system first as a base and then work up from their?

[Reid Malenfant]

I understand that Colin, i'd still recommend something better than the eggs for the rears though ;) What people often fail to understand is that there is still bass in the surround channels & in all honesty i'd hate to see you wanting something better a few months down the road :eyebrows:

Which i believe you would :doh:

[Reid Malenfant]

Maybe i should concentrate on setting up a good 2.1 system first as a base and then work up from their?
Good idea...

[colinB]

Cheers mark.
One thing about the sub. I take it to have any use at all it must be able to pressurise the room. In order to do that i guess im looking at hefty wattage specs, is that right mark? My present room is big compared with most of the rents ive had in London. It measures 9m by 5m.

[colinB]

Actually i think i know what you mean. Ive been in a cinema where the side speakers are rubbish. When you sit at the back and hear, say the clunk of a car door shutting , the sound feels like its coming from the front of the cinema.
In a good cinema the door sounds like its being closed right in front of you if that makes sense, and has a realistic fullness to it.

[Reid Malenfant]

Cheers mark.
One thing about the sub. I take it to have any use at all it must be able to pressurise the room. In order to do that i guess im looking at hefty wattage specs, is that right mark? My present room is big compared with most of the rents ive had in London. It measures 9m by 5m.
Wow! Actually you'll get some excellent deep bass in a room that size & you'll probably find the lowest room mode will be under 20Hz :)

You might not need loads of power but you'd definately be better off with a decent sized bass driver, say 12" as a minimum & 15" being better obviously.

[colinB]

oow! Thats big. So the driver is very important. Makes sense:)
You know the sound of the Nostromo in alien where alyou can hear is the machinary and engine sound that adds to the sense of dread? ( i bet Scott copied that idea from Das Boat) . I know that sound , i used to work in the bowels of a submarine when i was younger. If i could reproduce that in my room it would all be worth it :eyebrows:

[Reid Malenfant]

Colin, what front speakers are you using for your stereo?

[colinB]

I have AVI neutron 5s. The specs, which mean very little to me are,
120 Hz - 23khz+ or -2db and -6db at 65 KHz
They are 5 L volume, 87.5 db with a second order cross over (Linkwitz-Riley 3.4 KHz ):scratch:

[Reid Malenfant]

Ah, they are kind of tiny then, in fact about the same size as the original Wharfedale Diamond :eyebrows: You definately need a sub & it'll have to be a very musical one as well as it looks like it needs to extend up to 80 or possibly 90Hz :rolleyes:

There was me thinking you might have something that would get down to 40 or 50Hz :doh:

[colinB]

The REL t series i was looking at crossover is 30-120 hz with a 10" driver.
Sound allright?

[Reid Malenfant]

Possibly yes, if they are using the Tymphany (Peerless) XLS drive units it should be quite good :)

[colinB]

The BK one does for sure but im struggling understanding the specs as usual.
It just states -6db at 17hz :scratch:

[Reid Malenfant]

So it'll go below 20Hz... It'll probably do -3Db at 20Hz itself which is pretty good though it all depends at what level it can actually reproduce it. There is little point in being able to go down to 20Hz if it can only manage 90Db as that is only 15Db above audibility at that frequency :lol:

3607

In case you aren't quite understanding what -3Db means, it is a slight difference in volume, it's a bit lower. In the midrange we can detect a difference of 1Db or sometimes a tad less.

[Jac Hawk]

Watching kef eggs on e bay and various subs. Hope its all worth it.
Ive never heard a good system before, the ones i have heard have been all in one cinema in a box type and they have never impressed me, but im up for giving it a go.

Choosing the easy path only leads to the dark side young skywalker :lolsign:

[colinB]

LOL. Ok Obi-Wan i will take my time and avoid buying tat and do it properly.

[Jac Hawk]

Seriously though mate, you will find that the smaller your front pair are the more difficult it is to get a sub that can do that sort of range, be good at home cinema and music too.

I have a pair of Mordaunt Short MS45Ti's on 14 inch stands and my sub a yammy YST-SW80 (which is crap at home cinema by the way) is set at 50hz the lowest it can go and 180deg out of phase it was a doddle to set up realy but that's because i have large front speakers which do a lot of the low Hz donky work, (tell me if i'm wrong here mark) but the lower down the Hz scale the sub goes the more out of phase it will become, so if you're needing a sub to kick in at 80 or 90Hz say, but extend down to 20Hz it's going to be a tricky job to get a good compromise with regards to a phase setting so choose a sub which has a variable phase setting between 0 and 180 and you'll be covered and much happier with the results :)

[Jac Hawk]

LOL. Ok Obi-Wan i will take my time and avoid buying tat and do it properly.

Been on a Star Wars bender these last few days, can you tell? :lolsign:

[Reid Malenfant]

<snip> (tell me if i'm wrong here mark) but the lower down the Hz scale the sub goes the more out of phase it will become, so if you're needing a sub to kick in at 80 or 90Hz say, but extend down to 20Hz it's going to be a tricky job to get a good compromise with regards to a phase setting so choose a sub which has a variable phase setting between 0 and 180 and you'll be covered and much happier with the results :)
The higher up the sub has to reach the more problematic things become due to phase shift. Not quite the same thing but nearly. If you think about it 50Hz is a much longer wavelength & as it's pretty long it's relatively easy to get a sub in phase no matter what it's position (as long as there is a continuous shift control & a 180 degree switch). But at 100Hz the wavelength is shorter & the sub might need to be physically closer to the main speakers to get it in phase.

Phase will shift over a subs passband depending on the enclosure design, but as long as it's in phase at the point where the main speakers roll off it's not a problem.

As well as that it becomes more obvious where the sub is. I know people say that below 150Hz it all becomes omnidirectional, but i can often detect where a single sub is down to about 80Hz :scratch:

[colinB]

Seriously though mate, you will find that the smaller your front pair are the more difficult it is to get a sub that can do that sort of range, be good at home cinema and music too.

I have a pair of Mordaunt Short MS45Ti's on 14 inch stands and my sub a yammy YST-SW80 (which is crap at home cinema by the way) is set at 50hz the lowest it can go and 180deg out of phase it was a doddle to set up realy but that's because i have large front speakers which do a lot of the low Hz donky work, (tell me if i'm wrong here mark) but the lower down the Hz scale the sub goes the more out of phase it will become, so if you're needing a sub to kick in at 80 or 90Hz say, but extend down to 20Hz it's going to be a tricky job to get a good compromise with regards to a phase setting so choose a sub which has a variable phase setting between 0 and 180 and you'll be covered and much happier with the results :)

Ok. I think i get it. REL appear to have phase adjustments and high level in puts.
If it sounds bad im sure i will be able to sell it on. :cool:

[Jac Hawk]

Ok. I think i get it. REL appear to have phase adjustments and high level in puts.
If it sounds bad im sure i will be able to sell it on. :cool:

Very good sub mate, i'm looking at a few at the moment and the Rel and MJ Acoustics seem to be very nice, musical but able to dig deep for that real low cinema stuff too.

BTW Mark how's that new sub of yours shaping up

[Reid Malenfant]

BTW Mark how's that new sub of yours shaping up
I'm hoping to get to work on it in a month or so. Right now my hifi room looks like a bombs hit it as i'm sorting stuff out so i can get to this rack with plenty of room around so i can empty the thing of equipment :eek:

Will be just playing music from my PC for a few days while i get new stuff into the rack, list is here if you're interested (http://theartofsound.net/forum/showpost.php?p=177848&postcount=48), but you can add 2 Behringer 4 way active crossovers to that as well - just about to go fully active to :eyebrows:

Just got the dCS kit in there (http://theartofsound.net/forum/showpost.php?p=181426&postcount=51) last week as well :doh: Sorted out the slight pauses, it's been perfect for days now... Going to miss this quality :rolleyes:


But the end result will be worth it.