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Why use Monster as the reference cable?

It does not matter if they even agree with the setup before the test, when they fail and they will, they will find something wrong with the test, it will not be that they were wrong.

Paul

:) :) :)
 
Rolfe said:
"Alternatively, Linn Activamp modules may be fitted inside the Majik-I. Contact your dealer for more information."
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Linn makes active crossover and amp modules that bolt together inside the amp and are typically customized to match the speakers. This sounds like what you may have. I would however expect that miswiring the speakers would give you a very narrow frequency response bordering on unusable and not just poor.
 
Rolfe said:
Oh, I'm getting even more confused here, but this is getting interesting. Please forgive the derail.

No, the amp has no indication of which outputs are which other than red and black and left and right. It's the speakers that are labeled "treble" and "bass". I just assumed the upper outputs should connect to the treble and the lower to the bass.

This brings me back to my original suspicion, that the two sets of outputs might be identical. Which was the basis for my question about whether there was any benefit to the bi-wiring. To be honest, when I was checking out the system in the new house with the old speaker cables I was suspicious enough that that was so that I didn't make any effort to wire top-to-top and so on. That's what I was later thinking I must have done wrong.

However, having believed I heard better sound with the new cables, and being unable to see how different bits of wire could have made any real difference, I began to consider that maybe that had been a mistake.

When I said I switched the connectors on the speakers, I meant I swirched them top and bottom - so that the top set of amp outputs went into the bass and vice versa. That's what I was prepared to swear made the difference. That's what I thought people meant by connecting "out of phase". Did you think I meant swapping red for black? No, I've always had the red and black wired up right, I'm not colour blind!

So, what I thought made the difference, was switching round the top and bottom amp outputs into the speakers. Which, if the two sets of outputs are identical, should make no difference at all. In which case I was wildly mistaken, and it's another excellent example of how the ear can be fooled. I'll have to try it again, but really, I did think I perceived a difference.

There's no schematic or block diagram to help. The handbook does say, "The pre-amplifier and the power amplifier in the Majik-I are completely separate. This means you can upgrade your system by using an external power amplifier of even higher performance such as a Klout. To use the Majik-I as a pre-amplifier with another power amplifier, remove the two links connecting the pre out and the power in sockets, then connect the pre out sockets to the input sockets of the power amplifier. To use the Majik-I as a power amplifier, remove the links and connect the outputs of your pre-amplifier into the power in sockets on the Majik-I"

This has not been done on mine, I use it as a stand-alone amplifier. The handbook goes on....

"An external active crossover (e.g. Linn Kaber Activ) may be connected by connecting the pre out sockets to the input sockets on the crossover. Connect the treble out sockets from the crossover to the power in sockets on the Majik-I and use additional power amplifiers for midrange and bass. The Linn LK100, Klout and Majik-I power amplifiers are all compatible, as they have the same gain (28.5dB). Alternatively, Linn Activamp modules may be fitted inside the Majik-I. Contact your dealer for more information."

This last paragraph is the only place it starts to talk about treble and bass separately. I don't know enough about this to tell whether this means it really does have separate treble and bass capacity as it is, or whether the fact that the links connecting the pre out and power in sockets are still in place means there's nothing there.

Unfortunately I don't have the facilities to do a blind test switching the banana plugs top-to-bottom, so it's hard to know if I really fooled myself, if there is really no difference between the top and bottom speaker outputs. If there isn't, then I really must have fooled myself. I'm intrigued enough to try to get to the bottom of this.

When I bought the Majik and the Toukans, I didn't realise audio woo existed as such. I thought that once you were past a certain point the audible improvement for lots of extra money was likely to be so marginal that the price almost certainly wasn't worth it, but I didn't realise people were peddling "upgrades" that really and truly made no difference at all.

Now, however, I've seen a lot more that is obviously woo. And what Linn is saying about directionality of speaker cable is so obviously woo that I don't trust the rest of it. (Ivor, what's your opinion of the possibility that interconnects might be directional to some extent?)

So I'd love to know one way or another whether these two sets of speaker outputs are really identical or not.

Then I'd like to hear Ifor Tiefenbrun explain himself....

Rolfe.
Click to expand...

There is no way interconnects for audio could be directional, since they are pieces of wire.

The bolded section means that, as expected, the amplifier has a single power amplifier per channel (i.e. one for the left speaker and one for the right), and to use an active crossover requires additional amplifiers to drive the other speakers, ETA: unless you have Activamp modules installed. If there were any difference between the outputs in terms of frequency response they would and should be labeled, since it would be quite easy to destroy the tweeters if the bass output was accidentally switched with the treble.

I think the reason they suggest using the Majik for the treble output is because it 'only' has an output of 30 Watts per channel, whereas the other amplifiers mentioned can provide more power (50 and 85W for the LK100 and Klout, respectively). This is reasonable, since larger loudspeakers designed for low frequency reproduction usually require more power to drive them at a similar volume to speakers designed to reproduce higher frequencies. However, 30W input to most loudspeakers used in the home would certainly get the neighbours complaining.

As for the phasing problem that you 'cured' by switching the connections on the amplifier top for bottom, it does seem like you have managed to hear a difference that isn't there.

The simplest way (for me) to see if the two outputs are identical would be to measure the resistance between the two red terminals and the two black terminals. I'm very confident that the two like coloured connectors on each channel are directly connected to each other inside the amplifier, and are merely provided to make terminating bi-wired speakers easier.

If you really want to know, here's how to find out yourself:

1) Get yourself a digital multimeter with a resistance range. One like this will do.

2) Turn the control knob to the lowest resistance range. The black lead should be put in the black socket on the meter and the red lead in the red connector labeled 'V/ohms'. On the model shown that would be 200ohms full-scale (the 6-o'clock position), the black lead in the black-coloured socket at the bottom and the red lead in the red-coloured socket in the middle.

3) Disconnect the speaker wires from the amplifier and unplug the amplifier from the mains.

4) Check that the multimeter is working by shorting the red and black probes on the leads. The reading on the multimeter should give a reading close to zero ohms, certainly less than 1 ohm.

5) To check the resistance between the red connectors on the amplifier, connect one of the probes (red or black - it doesn't matter) of the multimeter to one of the red sockets on the amplifier, and the the other probe to the other socket of the same colour on the same channel. My guess is the meter will read a similar resistance to the one you observed in (4) i.e. a direct connection is present.

6) Do the same for the black connectors on the amplifier. Again, I' expect a very low resistance to be observed.

This may sound complicated, but in practice it's really simple and perfectly safe (for both you and your amplifier). If you do want to do it and have any questions, please feel free to ask.

The weak link in any audio system costing over a few hundred pounds is almost certainly the loudspeakers. Virtually every other single part of the system will be superior in performance by 1 or 2 orders of magnitude. What I find strange is that audiophiles will pay hundreds of pounds for "special" pieces of wire, when the biggest improvements are to be gained from linearizing the loudspeakers using motional feedback.

This works by sensing the motion of the speaker cone and allows the electronics in the amplifier to minimise any error using negative feedback. This technique is used in virtually every control system on the planet were high accuracy is required, including you and me (proprioception), except, for some reason, in high-end consumer audio, where the speakers are always driven open-loop.:confused:
 
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Ivor the Engineer said:
This works by sensing the motion of the speaker cone and allows the electronics in the amplifier to minimise any error using negative feedback. This technique is used in virtually every control system on the planet were high accuracy is required, including you and me (proprioception), except, for some reason, in high-end consumer audio, where the speakers are always driven open-loop.:confused:
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There are some audiophile amps that appear to use negative feedback. The Parasound amps have damping ratios over 1000, and I don't know how they can do that without negative feedback. I read through their webpage and unlike other audiophile amp companies, Parasound makes no mention of negative feedback at all. Maybe audiophiles can enjoy an amp that uses negative feedback as long as they don't know it is there?

Here's a pretty good article about negative feedback and how using it can sometimes cause problems:

http://www.normankoren.com/Audio/FeedbackFidelity.html

Part 1 covers preamps and Part 2 has information on power amps. There are some interesting simulations showing how feedback makes clipping distortion more audible.
 
Those problems with negative feedback no longer exist when you include the speaker in the feedback loop. Clipping occurs when you exceed the limitations of the amp. If the speaker is included in the loop, the limitation is the physical travel of the speaker cone. If you exceed that limit you end up with physical damage to the speaker.
 
bjb said:
There are some audiophile amps that appear to use negative feedback. The Parasound amps have damping ratios over 1000, and I don't know how they can do that without negative feedback. I read through their webpage and unlike other audiophile amp companies, Parasound makes no mention of negative feedback at all. Maybe audiophiles can enjoy an amp that uses negative feedback as long as they don't know it is there?

Here's a pretty good article about negative feedback and how using it can sometimes cause problems:

http://www.normankoren.com/Audio/FeedbackFidelity.html

Part 1 covers preamps and Part 2 has information on power amps. There are some interesting simulations showing how feedback makes clipping distortion more audible.
Click to expand...

The damping factor is another concept that is often misunderstood. It is simply the speaker impedance divided by the output impedance of the amplifier. Once the output impedance of the amplifier is 1/10th that of the loudspeaker, it's going to have very little effect on the damping of the system. I.e. the series resistance of the loudspeaker will dominate the amount of control the amplifier ultimately has over the movement of the cone.

What is required is a way to sense the movement of the cone, convert it to an electrical signal and apply it as negative feedback. There are a number of ways of doing this, such as positive current feedback (used in motor controllers to reduce the effects of load on rotational speed), accelerometers, sense coils, etc. The important point is they provide a signal proportional to the motion of the cone, which can be used to correct for non-linearities in the speaker.

Motional feedback only really needs to be used for low-frequency drivers, since once you get up to 1-2kHz, most speakers are only going to be moving a tiny amount at volumes acceptable for use in the home.

The other great thing about using motional feedback is that the enclosure volume becomes less of an issue, since it no longer dominates the low-frequency response. As long as the amplifier can provide enough power (and the speaker not melt), the low-frequency response is determined by the low-level equalization before the power amplifier.
 
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Ivor the Engineer said:
There is no way interconnects for audio could be directional, since they are pieces of wire.

The bolded section means that, as expected, the amplifier has a single power amplifier per channel (i.e. one for the left speaker and one for the right), and to use an active crossover requires additional amplifiers to drive the other speakers, ETA: unless you have Activamp modules installed. If there were any difference between the outputs in terms of frequency response they would and should be labeled, since it would be quite easy to destroy the tweeters if the bass output was accidentally switched with the treble.
Click to expand...


Update. I haven't done Ivor's suggested test as I don't have easy access to a multimeter. I intend to do some more listening tests but I need to set aside a reasonable length of time. However, it's a bit academic because I think it's self-evident he's right.

I've remembered the details of acquiring the system now. After I acquired a second-hand Sondek, I decided to upgrade the amp and speakers to match. At first I ignored the hard sell I was getting on the biwiring issue, and just used the old 79 speaker cables from the old system. I remember now being told it didn't matter which set of outputs from the amp I used, and concluding from that that the two sets of outputs (unlabelled) must be identical, and so the biwiring thing was probably woo.

However, some time later, I decided to clear the decks and give the old turntable, amp and speakers to a friend. The only missing item was the speaker cable, of which I had only one set. It was at this point I decided to purchase new speaker cable for my own system, and succumbed to the biwiring spiel. The speakers had to be modified but this was very simple, just removing metal plates connecting the treble and bass inputs on each speaker. I was sceptical that there was any scope for an effect, given that the amp outputs appeared to be identical, but it was completely impossible to test it in any meaningful way.

When I set the system up in the New House, I remembered that I'd had the idea the biwiring was woo, and it shouldn't matter which way round the speakers were connected. (Talking treble/bass here, not positive/negative.) However, when I bought the new Bose cable, for logistical reasons as described, I actually took care to connect them the way that seemed right, assuming the top set of outputs were the treble - but I was confused by the absence of any labelling. I think Ivor is right, and it's the absence of this that clinches it.

I was subsequently surprised by how good the system now seemed to sound, and began to wonder if I'd been mistaken, and this was actually an important consideration I'd got wrong previously. That was when I tried the listening test, and thought I was sure the system sounded worse when the connectors were switched top to bottom. Clearly, I must have been imagining that, and that's what I want to try again to see what I was imagining!

I'd be inclined to assume that the difference I thought I heard with the new cable was in fact due to speaker positioning, however that wasn't a consideration in that last test, which does rather suggest that even though I wasn't expecting an improvement I somehow manufactured one.

The subjectivity of this reminds me of an account in the book Ring Resounding, of the first stereo recording of Das Rheingold. During a press conference, the producer told a bunch of journalists to listen out for the Rhinemaidens' trio at the very end, and note how the recording made them appear to sing from below the level of the rest of the sound. This is in fact impossible, ordinary stereo will only do horizontal placement, as the producer freely admitted in the book. He noted his vast amusement when several of the journalists dutifully reported being impressed by the way the Rhinemaidens sounded as if they were singing from below, at the end.

There's no doubt hifi sounds better than a portable tranny. (The evening of Chillzero's birthday bash, I coincidentally got home just as a Radio 3 broadcast of Gotterdammerung was beginning. I said oh good, and settled down to listen. But I couldn't even listen to it on the kitchen tranny, and the hifi was still packed in boxes at that point.) And good hifi will usually beat a cheapo system. However, the amount of woo going around is distressing.

I don't doubt Linn make good audio. But when their product handbooks (1998 vintage, so a fair bit earlier than the major audio woo we've discussed in ither threads) contain such clear misinformation about directionality of speaker cables and the benefits of biwiring a system where both wires are carrying the same signal, it really stops me trusting Ifor's bunch, about anything.

Rolfe.
 
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