• If you ever spot Spam (either in the forums, or received via forum direct message) please use the Report button at the bottom of each post to make sure a Moderator can handle it quickly. Thanks for your help in keeping things running smoothly!

Widening the Stereo Field

jedaisoul

Member
May 16, 2020
15
0
20
I hope that members will be interested in an idea I have for widening the stereo field produced from conventional stereo recordings. I have developed a computer model which indicates that four speakers placed in an arc thirty degrees apart could achieve a stereo field up to sixty degrees wide. Similar results could be achieved with six speakers placed twenty-four degrees apart, but this requires some adjustment of the signal levels to operate optimally.

If you have a analogue stereo source, with a stereo male-to-male phono output cable, and a 5.1 AV system with a multi-channel analogue input, you may just need a few RCA phono "Y" splitter cables to convert the AV system to four channel stereo:
1. Disconnect and put aside the Centre speaker.
2. Move the Front speakers closer together such that the distance between them is half the distance from the speakers to the listening position. E.g. If the speakers are three metres away from the listening position, place the speakers 1.5 metres apart (distances measured from the front centre of each speaker).
3. Move the Surround speakers to the side of the Front speakers, maintaining the speaker-to-speaker spacing.
4. Plug the two male phono connectors of a "Y" splitter cable into the Left Front and Left Surround sockets of the multi-channel input.
5. Plug the Left Output cable of your stereo source into the female connector of the "Y" splitter cable.
6. Repeat steps 4 and 5 to link the Right Output cable from the stereo source to the Right Front and Right Surround sockets of the multi-channel input.
7. Depending on how your AV amplifier derives a signal for a Subwoofer, you may need to add a cable between the Left output from the stereo source to the Subwoofer socket of the multi-channel input.
8. If you add a cable at step 7, you may need to add a further cable between the Right output from the stereo source and the Centre socket of the multi-channel input. This may seem odd, as the centre channel is not used, but it is simply to balance the input loads. If it makes no audible difference, it can be omitted.

I find that the change from two speakers to four is significant. Changing from four speakers to six is more subtle.
 

12th Monkey

Well-known member
Aug 31, 2015
677
414
11,270
Or you could just move the speakers apart/use a better DAC?

Besides, AV amps aren't known for their stellar performance with music, and adding additional speakers will surely blur the image you create.
 

abacus

Well-known member
Sep 24, 2008
402
160
19,070
Most AV Receivers have something similar built in as standard, (Either processed or using additional wide speakers) however 2 speakers set up correctly is still hard to beat.

As a rule of thumb if you half the price of an AV Receiver then this is the type of sound you will get from a dedicated stereo amp of that price. (If you go hi-end AV then the differences diminish and they sound just as good as a dedicated stereo amp)

Bill
 

12th Monkey

Well-known member
Aug 31, 2015
677
414
11,270
Re the last point - I don't see how they can do, at least at the same price point. The AV amp includes all sorts of complicated processing electronics and many more channels of amplification built in. Ergo if developed with equal skill and resources, the dedicated unit will be better at two channel.
 
  • Like
Reactions: Al ears

abacus

Well-known member
Sep 24, 2008
402
160
19,070
Re the last point - I don't see how they can do, at least at the same price point. The AV amp includes all sorts of complicated processing electronics and many more channels of amplification built in. Ergo if developed with equal skill and resources, the dedicated unit will be better at two channel.
Never said they could, what I said was that their quality sound wise was equivalent to a dedicated stereo amp at half their price. (A £1000 AV will have roughly the same sound quality as a £500 stereo amp)

When you go high end most users have separate pre-power amp combinations so are pretty much on par with stereo amps. (Most users separate at high end)

If all the processing of an AV was done in the analogue domain there would be big differences, however as all processing is done in the digital domain, when you come to a certain level (Quality components, DACs etc.) they are pretty much completely transparent.

Bill
 

jedaisoul

Member
May 16, 2020
15
0
20
Thank you for your comments:
Or you could just move the speakers apart/use a better DAC?
My objective is to achieve a 60 degree stereo field. In my experience, when you increase the speaker-to-speaker spacing much above 30 degrees the dilation of the central images (the "hole-in-the-middle" effect) is clearly apparent. I can't see how a better DAC could overcome that?

Besides, AV amps aren't known for their stellar performance with music, and adding additional speakers will surely blur the image you create.
I want to encourage members to set up a test system and draw their own conclusions. AV systems contain almost everything you need for a four channel stereo system and can be obtained at little expense, particularly if they lack the latest AV bells and whistles. E.g. I use an old Kenwood Series 21 pre/power amp combo. But I also have a Rotel RKB-650 six channel power amplifier for comparison.

The idea that adding speakers will inherently blur the image seems logical, but it is not the whole story. I would suggest that the question we need to answer is: How acceptable are the central images with four speakers placed 30 degrees apart, compared to a pair of speakers placed 60 degrees apart (all other factors being equal)?

The possible answers are:
1. Both acceptable - so choose which you prefer.
2. Four speakers is clearly better than two.
3. Two is clearly better than four.
4. Both unacceptable - Wider stereo field is not for you.

I know which I choose, but I am hardly unbiased. So I am seeking a way that others can answer this for themselves without major cost.
 

jedaisoul

Member
May 16, 2020
15
0
20
Most AV Receivers have something similar built in as standard, (Either processed or using additional wide speakers)...
As far as I am aware, these proposals are uniquely different from the facilities built in. Principally, the Centre speaker is not used, nor are speakers at the rear. Nor is any "processing".
...however 2 speakers set up correctly is still hard to beat.

Bill
Have you tried two speakers spaced 60 degrees apart?
 

12th Monkey

Well-known member
Aug 31, 2015
677
414
11,270
All I can say is that my speakers are quite a long way apart, but there's very definitely no hole in the middle. (They are about 5m apart and I sit 5.5m away, so that's almost 60 degrees.)

I think you'd have to be pretty curious to follow such complicated setup instructions to see for yourself though - I know I won't be giving it a bash. But if you are happy, that's all that matters.
 
Last edited:
  • Like
Reactions: DougK

jedaisoul

Member
May 16, 2020
15
0
20
I think you'd have to be pretty curious to follow such complicated setup instructions to see for yourself though - I know I won't be giving it a bash. But if you are happy, that's all that matters.
The instructions are not that complex to follow, if you take them one step at a time. They just seem so when written down. But as you are happy with the performance of your system, why would you bother?
 

abacus

Well-known member
Sep 24, 2008
402
160
19,070
Most AV Receivers allow outputs to be assigned for wide speakers with the rest also being programmable; therefore if you don’t want the centre and rear to sound you turn them off.

Once you have the 4 speakers set up LR & LRW save it in one of the many pre-sets and you can choose it any time you want, (No need to jury rig cables) you can also still use the room correction system reduce room anomaly’s.

If you have a configurable Atmos system then it is even easier as you can put the speakers anywhere and assign the sound to come from where you want.

Bill
 

shadders

Well-known member
Nov 19, 2009
152
88
18,670
Besides, AV amps aren't known for their stellar performance with music,
Hi,
I disagree with this. The design of an A/V amplifier such as the topology (LTP input, VAS, output stage) is the same as a stereo amplifier. The transistors used are extremely cheap in large quantities.

It is just hifi folklore that A/V equipment is not as good as Hifi.

Regards,
Shadders.
 

12th Monkey

Well-known member
Aug 31, 2015
677
414
11,270
Hi,
I disagree with this. The design of an A/V amplifier such as the topology (LTP input, VAS, output stage) is the same as a stereo amplifier. The transistors used are extremely cheap in large quantities.

It is just hifi folklore that A/V equipment is not as good as Hifi.
I've said this elsewhere, but pound for pound it can't be - you are also paying for all the processing gubbins as well as diluting your budget over many more channels of amplification. I'm not saying AV can't sound as good with music as two-channel, just that you are going to have to spend a good deal more to get the same result.
 

12th Monkey

Well-known member
Aug 31, 2015
677
414
11,270
The instructions are not that complex to follow, if you take them one step at a time. They just seem so when written down. But as you are happy with the performance of your system, why would you bother?
Well, they look reasonably involved to a dullard like me!

Thinking about it, the soundstage is wider than the gap between the speakers, as with some recordings instruments are a little 'beyond' the speakers. I think I have about 60° and definitely no gap. What kit do you have?
 

shadders

Well-known member
Nov 19, 2009
152
88
18,670
I've said this elsewhere, but pound for pound it can't be - you are also paying for all the processing gubbins as well as diluting your budget over many more channels of amplification. I'm not saying AV can't sound as good with music as two-channel, just that you are going to have to spend a good deal more to get the same result.
Hi,
With the A/V amplifiers, there is the benefit of mass production and reduction of costs due to volume discounts. I don't have any figures for A/V amplifier sales, but i expect that they vastly outsell hifi amplifiers. Since many amplifiers have the same or similar topology, there is no reason that the topology changes for A/V amplifiers, and so their sound quality, is commensurate with hifi amplifiers.

Regards,
Shadders.
 

12th Monkey

Well-known member
Aug 31, 2015
677
414
11,270
Supporting your argument with two suppositions (that AV outsells Hifi by a massive margin and that this generates discounts of such a massive magnitude) ain't the strongest of cases...

;)

(I do expect you are right, and that AV amps outsell two-channel, and that this does generate some discount - but the AV amp is (I suspect) massively outsold by the soundbar - it's not the largest of niches either, even if it is a larger market than hifi. And it's not as though the likes of Cambridge Audio and NAD buy their transistors from Maplin* in batches of three or four (*I do know Maplin has gone under - just can't think of another example!) Thinking about it, many manufacturers make stereo and AV amps - they'd be getting discounts across the board and if these were as big as you suggest these companies would make better stereo amps than those who just make hifi. I don't see that being the case.)

Thinking about this a bit more, I know iro 100 people well enough to know what they watch/listen with (and I mean people I physically know, not the unrepresentative sample found online), and of those I think three have AV amps - which include me and my brother. I know a similar number who pipe their TVs through their stereos. Doesn't necessarily tell us a great deal about the respective market sizes, but they are a greatly varied demographic in terms of ages, wealth and interests.
 
Last edited:

shadders

Well-known member
Nov 19, 2009
152
88
18,670
Supporting your argument with two suppositions (that AV outsells Hifi by a massive margin and that this generates discounts of such a massive magnitude) ain't the strongest of cases...

;)

(I do expect you are right, and that AV amps outsell two-channel, and that this does generate some discount - but the AV amp is (I suspect) massively outsold by the soundbar - it's not the largest of niches either, even if it is a larger market than hifi. And it's not as though the likes of Cambridge Audio and NAD buy their transistors from Maplin* in batches of three or four (*I do know Maplin has gone under - just can't think of another example!))
Hi,
This is odd - your later text does not show.

I have made assumptions - which you later agree with, and in another thread i mentioned that a well specified (performance) single channel of an amplifier requires £14.39 worth of transistors from Farnell - costed for single unit purchases. This will probably half for multiple purchasing - so £15.00 for transistors only per stereo amplifier.

The cost of components reducing with volume is real - you can search Farnell, RS, Mouser, Digikey and see the breakpoints. As an example, one of the best output transistors is the MJL3281 :

Cost for a single device is £3.24, and cost for 1000+ is £1.46 - so half the cost. For small signal transistors, the price reduction is 75% = 1/4 of the cost.

So, one of the suppositions is fact. I have tried to obtain the figures for the number of units sold for A/V amplifiers - but it is difficult to find.

Regards,
Shadders.
 
Last edited:

12th Monkey

Well-known member
Aug 31, 2015
677
414
11,270
Sorry, it's not fact - you have supposed hifi manufacturers buy them in batches of one! And I wasn't agreeing with you, merely saying that there was something to your points, but nothing like enough to substantiate the argument.

I think I'll bow out of this one now...
 

shadders

Well-known member
Nov 19, 2009
152
88
18,670
Sorry, it's not fact - you have supposed hifi manufacturers buy them in batches of one! And I wasn't agreeing with you, merely saying that there was something to your points, but nothing like enough to substantiate the argument.

I think I'll bow out of this one now...
Hi,
I have stated that buying in bulk reduces the cost. The purchasing a single device cost was used to show that even when you purchase devices at their most costly, even then the total cost for transistors is £14.29. I later showed examples of true cost reduction, which verifies what i have written. So it is fact.

Essentially, purchasing a £1,000 amplifier will require £15 worth of transistors. Of course you have to add casework, power supply, heatsink etc., which costs a lot, but the remaining resistors and capacitors for the amplifier will be minimal cost.

Regards,
Shadders.
 

jedaisoul

Member
May 16, 2020
15
0
20
Well, they look reasonably involved to a dullard like me!
I have an idea that may help... I have a number of prototype connection boxes that simplify the connections. Most of them also have switches to allow a range of adjustment, and a 2 channel setting to allow comparison between 6 channels and 2 channels. They are "hobbyist" grade, e.g. mostly plastic cases, hand written legends etc... I've been thinking of encouraging people to try the system by lending out the boxes. Would you (or anyone else reading this) be interested?
 

jedaisoul

Member
May 16, 2020
15
0
20
What kit do you have?
The equipment I have is plentiful, but decidedly inexpensive consumer grade kit. Mostly bought second hand, some almost heirlooms (they are that old)...

Signal sources:
CDs ripped to WAV files (I have the original CDs) hosted on Dell, Toshiba and Samsung laptops. Supplemented by TV and digital radio.

Amps:
Kenwood Series 21 5.1 Pre/Power combo (used as 4 channel).
Teac AG15-D 7.1 receiver (used as 6 channel).
Rotel RKB-650 power amp (6 channel).

Speakers:
Six Wharfedale Diamond 1's (plus 2 spares).
Six Ariston MSX-07 micro monitors (plus 2 spares).
Twelve Microlab FC330 micro satellite speakers (plus 2 spares).
JPW SW1 subwoofer (2 channel) powered and filtered.
Wharfedale PPS-1S subwoofer (powered).

Interconnects:
A mixture of home made and inexpensive cabling with gold plated connectors. I believe in keeping cabling as short as possible rather than buying expensive ones.

Not all the kit is set up at any one time.
 
Last edited:

jedaisoul

Member
May 16, 2020
15
0
20
Maybe we should consider development costs.
I'm concerned that could contravene the site rules. I've only just joined the site. I don't want to get banned! Besides which, I need feedback from others testing the units. That would be pay back enough.
 

ASK THE COMMUNITY

TRENDING THREADS