Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

The problem with better

This post is for those following along in the Music Room One saga. After Arnie Nudell came to reposition and adjust the IRSV system for optimum performance, nothing’s been quite the same since.
First it was the preamp. I run the great sounding tube preamp by Aesthetix, the Calypso. Within a week of Arnie’s visit one of the output tubes starting going on the Fritz, losing gain and sputtering. Ouch. Replacement 6H23s aren’t cheap. But replacing them transformed the sound for the better. Then Bascom took away the prototype amplifier which was just on loan and had to be returned. I reverted back to the last and best attempt at a reference amplifier in the meantime. Problem with this was two fold: the sound was good but once obvious differences in equipment were now significantly less so, which lead to the second problem. Depression. So much better was Bascom’s amp that upon its exit I simply could not bring myself to listen any longer unless I was asked to by engineering.
Then engineering finished the first prototype of the new power amplifier. That was exceptional and I was back in business. Almost. The sound was much improved, the system quite listenable, but fatiguing over time. There was a glare to the music. We suspected the small oscillation obvious on measurement equipment but had yet to figure out its cause, or its cure.

Now the oscillation is gone, the prototype sounding better than anything I have ever heard in Music Room One. Stunning really. That brought up the next issue, the source. Whenever things are in a state of uncertainty, upheaval, I always revert back to a known and trusted source. In this case the PerfectWave Transport. It’s been chugging along in that room for years. Old reliable.

Now that I am relaxed, the amplifier coming into its own, I branch out and fire up the Mac Mini server I wrote of months ago. Ugh. Sigh. Now this source, which formerly sounded just fine with the other power amplifiers in service, sounded rather lifeless compared with the PWT. It has since been retired and sent off to an upgrade service, something I swore I wouldn’t do.

So much for swearing.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Summing it all up

I think one of the major advantages to bi-amping is using different amps: each with their own qualities to add to the mix. I know this runs counter to many people’s opinions, but what the heck. This is mine.

Here’s the deal. I designed the active woofer systems for several loudspeaker companies and in each case I made sure the power amp module for that active woofer section was designed specifically for the application. I designed an amplifier that I would never suggest using on a full range loudspeaker, yet it’s wonderful for the application at hand. I have also assembled bi-amped system using a delicate tube for the top end and a brute for the bottom with great results.

This practice isn’t for the faint of heart. Matching levels and characteristics is only the first part of the problem, as we’ve discussed in earlier posts. The crossover is critical as well. I’ve used a derived analog crossover like those John Curl designed in the Symmetry crossover, intending to give perfect phase response, and had good success. I’ve also designed sloppy 6 and 12dB/octave passive filters with great success as well.

I guess the point of this is simple. If you’re going to go to the trouble of bi-amping you might as well go for the gusto and add an amp that glorifies the particular region of sound you’re trying to reproduce. In its simplest form, you can place a pot (attenuator) on the louder of the two amplifiers and, using a sine wave generator and a voltmeter, match levels pretty close to each other. Then you need only a crossover. Here I would shy away from active crossovers as you’re adding a whole new layer of grit and problems you probably don’t need. Remember, a passive crossover inside the loudspeaker is usually nothing more than a handful of caps, resistors and coils of wire.

You can better and more easily duplicate the same slopes as an internal crossover if you do it externally and with much better parts. For example, the impedance of a driver is typically 4 or 8 Ohms. This necessitates a very large cap and this, in turn, means the quality of the cap goes down as the size goes up. The typical input impedance of a power amp is 10,000 times higher, so the size of the cap can be 10,000 times smaller. As the size of the cap goes down the quality goes up.

These are just some ramblings about why I would either go for the gold with bi-amping or stick with bi-wiring if it looks to be too much of a task.

And, if you’re like me in my quest for simplicity, you’ll just get the very best cables you can, run a couple of monoblocks and call it good.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

If it were me …

If I were designing a loudspeaker system and wanted it not for commercial release but just for myself, I’d bi-amp it or even tri-amp it, using an electronic crossover in front of the amps. Why? Because traditional passive speaker crossovers in a loudspeaker are a compromise relative to what one could achieve with an electronic version. But speaker designers shy away from what has become known as ‘active speakers’ because, well, they just don’t sell. Speakers you have to plug into the wall outlet, with amplifiers and crossovers built in have traditionally been commercial failures. Customers seem to like to add their own amplification, thus the speaker must have an internal passive crossover.

So when we speak of bi-amping a loudspeaker we are trying to turn a compromised product solution into something a bit better. The speaker you’re bi-amping has an internal passive crossover separating the tweeter/midrange from the woofer. But there’s nothing better than putting the crossover in front of the amplifier, the amplifier’s output tied directly into the speaker’s driver.
Such is the situation we currently have in audio. To bi-amp in the traditional/classic method we need two identical power amplifiers and two identical speaker cables. This is the classic ‘missionary position’ concept of bi-amping. The advantages are total isolation between both the feeds to the loudspeaker, where bi-wiring only helps and does not provide all possible benefits of isolation.

What you want to make sure you’re doing correctly, when bi-amping, is keeping the gains of the amplifier identical and the amp’s inputs fed with the identical signal. But, how effective is this solution? How much better is it than bi-wiring? Is it worth doing? Have you taken full advantage of the potential?

I would have to suggest that unless you have a unique situation that no, it is not significantly better. Not enough, IMHO, that it’s even worth doing; unless. Unless you decide that you’re willing to really play and that ‘playing’ may run against the grain of traditionalists. But we’ve never shied away from running afoul of the Traditionalists, now have we?

Let’s dig a little deeper tomorrow.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Is one enough?

Recently we’ve been chewing the fat on bi-wiring, now it’s time to take it up a notch: bi-amping. Bi-amping is the ultimate bi-wiring. Not only do you have two separate loudspeaker connecting cables, one for the top end and one for the bottom end of the speaker, you also have separate power amplifiers connecting each.
It’s pretty hard to mess up a bi-wire situation. The same cannot be said for a bi-amp setup. Now the chances for error go up dramatically.

One of the issues I’ve seen is when people willy nilly connect their favorite power amp to the top end and a different amp for the bass. Here’s an example. Let’s say your favorite amp is a little sweet sounding tube power amplifier. Maybe a single tube that has but a few watts available to it. Sure everything sounds warm and rounded, but the bass sucks. It’d have to, these kinds of power amps have output transformers, near zero damping factor and, of course, very few watts. So you decide to bi-amp: use this little tube amp on the top end powering only your tweeter. Then you drag out the old beast of a solid state amp you had laying around and throw it on the woofer. Great choice! Now you have all the power in the world for the woofer, a sweet sounding tube on the top end. Life should be good. You turn the system on and it sounds dreadful. What happened?

The biggest problem with doing this is that each of the two power amplifiers likely have different gains. So, now what do you do?
Tomorrow I’ll start to detail out the advantages and disadvantages of bi-amping and we’ll get into this interesting subject.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Building cables

If you want to make a decent sounding speaker cable it’s not terribly difficult. Go down to Home Depot and buy yourself a roll of 12/3 Romex cable. Cut two identical lengths and use the one for + (red) and the other length for – (black). Each of the two lengths has three solid core copper wires inside. Take the center one and strip it back long enough to work into your speaker and amplifier’s binding posts. Take the other two conductors, strip them back and tie them in parallel to the center one a reasonable distance back, say six inches, leaving the center one sticking out to connect to the binding posts. Then, repeat the process for the other channel. You now have a decent sounding speaker cable for about $20.

No, it doesn’t look pretty, no it isn’t spectacular sounding, but it’s actually pretty darned good. It uses a couple of techniques that are important for us to understand if we’re interested in learning how to make cables sound good. They work because they use multiple, separately insulated solid core conductors. These multiple conductors have a good deal of surface area that helps the higher frequencies travel easily down the wire, yet a decent amount of solid internal ‘meat’ inside each of the conductors to help with bass.
These cables don’t have the greatest low frequency control and impact nor would they have the best top end. So, what might we do to improve both areas? For the bass notes we could add more ‘meat’ meaning another, heavier gauge solid core conductor in parallel. For the top end, we could do the opposite: add multiple smaller gauge solid core conductors in parallel. I think you get the idea.
These explain just a few of the rudimentary tools cable designers have at their disposal to ‘tune’ the sound of cables connecting amps to speakers. The other variables are many, including the types of insulation used for the conductors, the geometry of the conductors in relationship to each other (parallel, braided, right angles to each other etc.).

Tomorrow let’s start a discussion on bi-amping, moving up the scale from bi-wiring.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Mix and match

Yesterday I promised we’d go over one of the significant advantages of using separate speaker cables for the top and bottom end of the loudspeaker. The practice is known as bi-wiring.

The general notion is that by separating the tweeter/midrange signals from the bass signals in separate cables, benefits of isolation are achieved. It’s been suggested in the comments section of Paul’s Posts that one benefit is isolating the back EMF from the woofer and lowering magnetic fields generated by the heavier current demands of the bass frequencies. While not convinced about the magnetic isolation benefits, clearly the back EMF arguments have merit.
EMF stands for Electro Motive Force. Sounds tricky but it’s not. A woofer can act both as a microphone and as a driver. Put energy into that driver and it moves forward or backwards depending on the polarity of the energy you put in. But take your hand and push the woofer in and the same mechanism that moved the woofer now does the opposite: it becomes a generator and produces voltage. So every time the amp moves the speaker, the speaker ‘pushes’ back creating a voltage. That’s what’s being discussed here. Not having that ‘extra’ voltage from the woofer on the same wire as the tweeter and midrange could definitely have some benefits. And bi-wiring works, so, ok, I am a believer.

But to the subject of today’s post, mixing and matching: using different cable constructions for each of the two speaker cable types. We’ve all heard differences in speaker cables. If you haven’t, then you need to experiment a bit. Trust me, they exist. One cable might have great slam, impact and bass response while another sounds thin and anemic in that area, but terrific on the top end. I am sure you can see where this is going. By selecting different cable constructions maximizing the benefits of top end or bass performance, separate cables can sound far better than a single cable trying to be good at everything.

This idea has been around for some time now. Generally, heavy gauge cables sound full and rich in the bass, but depending on how they are constructed, not always the best performers on the top end. This type of cable would most likely work great for the bottom end cable.

So, now that you know how to maximize a bi-wire setup the question probably comes to mind ‘how do cable manufacturers wind up making a single cable with both characteristics’?
I’ll give you some insight into this tomorrow.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Star wiring

Yesterday I wrote about bi-wiring and shotgun wiring to your loudspeakers. Bi-wire uses a separate high and low loudspeaker cable feeding two separate inputs on your speakers. Shotgun uses two speaker cables in parallel feeding one set of terminals on your speakers.

Today let’s touch on bi-wire specifics. If you take two identical speaker cables, tie both of them together at the amplifier output binding posts and feed the separated high and low binding posts on the loudspeaker, that’s a pure example of bi-wiring. Advantages are the current for the midrange and treble are isolated in one cable and the bass power isolated in the second cable. But why should that matter? I have never heard an engineering example of why this is better that I believe. Lots of theories shrouded in the mists of Audiophelia, but none I would ever present to our engineering group without fear of a few smiles and smirks.

The closest I have come to getting a reasonable explanation is making use of a classic wiring technique known as star wiring. In this technique, one we routinely use for our grounds in the equipment we design, all major pathways for ground currents return to one common point, making a pattern similar to a multi faceted star, as each separated branch fans out from the center of the star. The advantage to this is in keeping the impedance constant for all branches, the noise on the grounds separated. The technique is similar to that of running dedicated lines in your AC system. The power amplifier’s terminals, in this case, would be the star reference point. Thin reason for sounding better, but at least it has some merit.
Tomorrow I’ll tell you the real advantage of a bi-wire situation. One that’s easy to understand.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Bi-wire

How daring are you with your system? Have you ever tried to bi-wire it?

Bi-wiring means to split the output power from your amplifier into two separate speaker cables: one for the top end and one for the bottom end. You can also tri-wire, of course, but that’s rarely done.
So, how important is bi-wiring? And do you need to have two inputs on your loudspeakers to have it effective?

Bill Low reminded me that a simple change of wire positioning, on a loudspeaker pair with separate inputs for bass and treble, can make a noticeable difference. He tells a story of going to a dealer’s showroom, playing music for the staff on their reference system, then going around to the rear of the speaker, making a quick ‘mystery’ change they all noticed for the better. What he did was simple: move the speaker cables from the bass input terminals to the tweeter input terminals, when the two are tied together with a set of jumpers. Indeed, I’ve performed this experiment myself on several occasions, each time enjoying a noticeable improvement.
So when we take that ‘trick’ a step further and use two pair of speaker cables to connect the amp and loudspeaker together, the results can be even more dramatic.

In Music Room One I have a treasured pair of MG Audio Planus III speaker cables that are in a ‘shotgun’ configuration. To me this is the best of both worlds: two parallel speaker cables, each separate until the very last moment, terminated into one set of spade lugs at the amp and loudspeaker ends. And here’s what’s interesting and perhaps misunderstood. Shotgun is not bi-wire despite the fact there are two speaker cables in both cases. The term bi-wire is only accurate when separated by high and low frequency inputs on the loudspeaker, thus separating and isolating the currents in the wire. Shotgun is merely doubling the speaker cables but I find that approach better sounding.

But if you’re not up for the expense of bi-wire or shotgun style, at least pay attention to Bill Low’s trick if your speakers have separate binding posts: go high first.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Minority report

In a conversation with a customer over the weekend the question was posed to me: “Do you think it’ll ever be possible to bring high-performance sound to the masses?”

The answer to that question is easy: no. But not for technical reasons.

‘The masses’ aren’t typically interested in high-performance sound. It’s a funny twist. I have rarely seen anyone that didn’t appreciate hearing better sound, yet those same people wouldn’t pay a plugged nickel to improve theirs. It seems high end sound is more of an interesting curiosity to some, like looking at a fancy sports car, than a goal many people have to acquire it. Home theaters aren’t a lot different. You show someone an awesome home theater and they love it, reveling in the experience. But own it? Even if they could?

Yawn.

We always seem to want to convince those around us to think like us, eat like us, look like us. But not everyone wants to or will join the club. Let’s face it. The term ‘the masses’ probably means ‘people not like us’.

It’s ok to be in the minority.

Asheville, North Carolina ‘s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Musing about music

Music fascinates me. I am guessing you’re not much different if you read this column. Sure we all like hardware and playing with the toys but without something to play on the toys there isn’t much point to it. We play music.

The word ‘music’ in English comes from the Greek word ‘mousike’ that means coming from the Muses. If you’re into the arts you know about the muses. All art was thought to have come from the muses: the nine daughters of the gods Zeus and Mnemosyne. Today, composers, authors, poets and artists of all kinds still invite the muses to sing through them, write through them, rhyme through them and act through them.

When you create anything your inspiration comes from the muses, that creative fire that burns within us all. Call it what you will.
I know this might sound silly, but I think one of the missions we Audiophiles have is to help the world enjoy music in its purest form; to make known there is a pure form of sound possible; to remind the world how good music can sound; to bring us as close to the purity of live sound as is possible. For are we not artists ourselves when we assemble systems that sing?

I just had the most remarkable experience last weekend: listening to music in Music Room One through the new power amp, now in its fourth week of burning in and just beginning to come into its own.
My guess is its found a connection to its muse.