Tag Archives: bass

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Endless variations

It is fascinating to me the myriad of seemingly endless variations designers apply to sound reproduction equipment.

Take the rarely seen today bipole loudspeaker. The last mass-produced version I remember was by the Canadian company, Mirage.

Let’s start with a smidge of reference. Most loudspeakers are monopoles: sound comes out of one plane of the speaker box. A smaller number are dipoles: sound comes out of two planes (front and rear) and the rear plane is out of phase with the front. A bipole is like a dipole in that it too has front and rear radiating planes, but instead of being out of phase the front and rear are in phase.

Perhaps the easiest way to picture a bipole is the idea of a pulsating cylinder, though not in the same way you might think of an MBL (which literally is a pulsating sphere). In the bipole, the same woofer, midrange, and tweeter drivers that you find in the front of the speaker are duplicated on the rear of the speaker—all wired in phase.

The acoustic pattern that is created is somewhat of a figure 8.

The bipole had some advantages, like fewer sidewall issues than monopoles, but for the most part I never really found the configuration very attractive—and it had a number of the problems we associate with dipoles and open baffle speakers—sans the bass cancellation problems.

If you’re curious about the Mirage speakers, there’s a well written review by Tom Norton in this issue of Stereophile.

What’s interesting to me about this design is that it’s but one more attempt by clever people to build a speaker that differentiated itself from the pack. One more twist to an ever-evolving evolution in the art of making high end audio products.

The variations at times seem endless.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl

I just listened in Living for the City via Qobuz and while not thin, pretty veiled sounding. Still fun to listen to, as is the entire album.

Living for the city
As long as we’re getting nostalgic, I am remembering the first truly audiophile disc I became enamored with. Stevie Wonder’s Living for the City from his album, Innervisions.

What a great piece of music. I remember cranking that tune up on our friend Norm Little’s tri-amped Audio Research system and being just blown away at how it sounded.

The bass was magnificent as reproduced through a pair of Cerwin Vega 18″ woofers.

It had never occurred to me how pumped up and inflated those woofers must have been.

The reason I mention that bass inflation was because today, that record (or CD) sounds anemic. On our finely tuned systems where we work hard at keeping everything flat, that track of Stevie Wonder’s music is wimpy: clearly rolled off in the bottom end by some well meaning recording/mastering engineer.

Going back through my list of favorite music tracks from the 70s and 80s it’s pretty clear none of them had any real deep bass (which makes sense because back then, it was assumed the best systems went down to maybe 40Hz and most rarely went below 60Hz). And since we always tuned the sub’s output by ear to accommodate the music we listened to, we could get perfection in the lower end.

In later decades the recording industry began using full-range recording and reproduction equipment. By the late 1990s and early 2000s recordings began having full extension bottom end. We adjusted our systems accordingly.

The end result, of course, is that modern recordings sound correct and older recordings sound defficient.

As eras and technology change so too do our reproduction systems.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

The asymmetrical room

Customers often send me drawings of their stereo rooms. One of their biggest worries seems to be when the room is not symmetrical. And their greatest angst seems to occur if one side of the room opens wide into another part of the home.

Because one side of the room opens into another, the question becomes how in the heck to get good imaging if one channel has a sidewall while the other does not?

I am here to tell you you’re probably luckier than most.

Through setup we can always work around the sidewall problem using absorbers or diffusers or simply positioning. What we cannot easily fix is the bass problem. Enclosed rooms generally have lousy low frequency support. Between the standing waves that bunch up at the boundaries and the lack of room for long wavelengths to do their thing, bass suffers.

Those lucky enough to have a room where one wall opens into the rest of the house generally have plenty of area for bass to prosper.

Solving the sidewall asymmetry is easy compared to the bass problem.

If I have a choice, I’ll go for the open room every time.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

This depends a lot on the loudspeaker design. Paul uses Infinity IRSs, which are line source, planar magnetic drivers for the tweeters and midranges and they are designed to be used the way he uses them.

Fractions matter

In yesterday’s post, we looked at long wavelength bass notes—some exceeding 50 feet in length. Today, let’s have a look at their shorter cousins, high frequencies.

Where bass frequencies are typically multiple feet in length, higher frequencies are generally in inches or fractions of an inch. 1kHz, for example, is right around 1 foot, while 10kHz is a little more than an inch.

When it comes to system setup what makes these frequencies challenging is their very short wavelength. You can imagine toeing in or out one channel’s loudspeaker a “skosh” and making a very big sonic difference.

The short wavelengths of higher frequencies are one reason I have long been an advocate of relying upon the off-axis response of the system for best imaging (as opposed to pointing tweeters directly at your ears). In my setups you’ll almost always notice the left and right speakers are nearly without toe-in, pointing instead almost straight ahead. The energy distribution of the off-axis response is much smoother and less prone to laser-like problems we get when we rely instead upon a perfect triangulated setup of speakers.

Fractions matter when it comes to higher frequencies but one can mitigate some of this specificity by relying instead upon speakers with excellent off-axis response.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Working together

I am pretty certain few rooms support perfect bass. It’s not that rooms are particularly biased against low frequencies, the problem is those pesky long wavelengths.

Consider that a 20Hz wave is 51 feet in length. A 30Hz note is 38 feet long and even a 60Hz note is just under 10 feet in length.

These long wavelengths mean they don’t fit into most rooms, so, with nowhere to go they bunch up like the bellows of an accordion. This squeezing of sound creates hot spots and dead spots within the room.

What to do?

The easiest is to find where in the room you can sit that has the smoothest response for the greatest number of frequencies. That, coupled with moving your loudspeakers without mucking everything else up (like imaging and tonal balance), is the best way to make the most out of a tough situation.

Indeed, there are other means like adding digital correction and, if your bass is generated out of a subwoofer or separate woofer enclosure that can both be moved as well as digitally manipulated, then that’s a positive step forward.

What I don’t advise is to digitally manipulate anything other than bass frequencies—something requiring a separation of the woofer from the rest of the speaker.

As I cover in The Audiophile’s Guide, finding the best spot in the room for bass is a bit of a compromise, but it’s better to work together with the problems than wage war upon them.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Out of balance

When something is out of balance we often blame what stands out most. For example, if music sounds overly bright we naturally pin the blame on that area of frequencies.

We might be completely wrong.

Imagine the treble regions being perfect but the midrange and mid bass areas a bit repressed. It’ll sound bright.

Over the years, one of the tricks I’ve learned is to pay close attention to the quality of the area under question. If it sounds “too bright” I first focus my attention on the problem region by switching to music that naturally emphasizes it: cymbals, brushes, sibilance, upper harmonics. If these are intact and perfect, then I know to look elsewhere.

It’s easy to jump to conclusions and point a finger at what’s obvious.

But it often pays to look a little deeper to see if the balance between frequencies might just be off.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Hard to imagine

When Stereophile reviewer Michael Fremer writes “on electric bass… the M1200 is a monster”, he’s not alone. More and more emails daily come across my screen extolling the virtues of the M1200’s bass.

How can it be that one flat measuring power amplifier can sound remarkably more powerful in one area than another?

Flat is flat, right?

Not so fast. Let’s have a closer look at the M1200’s measurements. 10Hz – 20KHz +/- 0.5dB

A measurement of 10Hz – 20KHz +/- 0.5dB says a lot if you look closely (and know what you’re looking for). What’s first apparent is its ruler flat performance within the range of human hearing.

But a deeper look shows something else: the amp is down at 10Hz by only 1/2dB. This is important because it means that an octave higher the amp is perfectly flat. Ruler flat response within the audible band is critical for removing phase shift. Turns out the ear is very sensitive to phase shift and the way to keep the phase from shifting is to start any measurable roll off well below the limits of human hearing.

You see, most power amplifiers will have specs that are more like -3dB at 10Hz (-3dB is important because it’s believed that’s where the ear perceives a level change). Fine that the point we first perceive a level change is below the ear’s frequency limits but what’s not mentioned is the phase shift. To be -3dB at 10Hz means you’re 1/2dB down point is well up into the audible range of bass—and we get phase shift.

When phase shift happens in the audible frequency range it will convince the ear the bass sounds wimpy.

And one more point.

A monster amp like the M1200 not only has no phase shift in the audible bass regions, it also has the power and reserves to effortlessly deliver that phase free note without any change in character.

Measurements aren’t always clear and simple.

The story behind the measurements matter.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

My seating position isn’t compromised, as my room was purposefully built for listening to music, but for almost all of us, what Paul is saying, is true.

The perfect spot

Your seating position is compromised.

If you’ve done your system setup homework your chair sits at a comfortable distance from the loudspeakers. With the precision of a ruler, you’ve tweaked and adjusted the speaker’s position for best imaging.

Though we call it the sweet spot, it’s certainly not the perfect spot.

Within the boundaries of most rooms, the perfect spot cannot be attained because of our old nemesis, bass.

If we could see sound we’d be rather shocked at how low frequencies bunch together like an angry sea of waves and throughs. Not far from your sweet spot bass notes boom. Move in the opposite direction and we hardly hear any low-frequency energy.

The perfect spot is where compromise negotiates a truce with boundary limitations.

Which is why we call our listening position sweet rather than perfect.

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Amen to this and most folks I know don’t have a lot of options when it comes to loudspeaker placement. I do and have the marks on the carpet to prove I’ve tried a bunch of different locations and it seems each speaker is different. Sometimes, changing electronics has me change things a bunch.

However, as I get older, I justs want to listen and where my Daedalus Ulysses speakers are now, works great, so I’m done…Probably…

Speaker placement

There’s perhaps nothing more important than speaker placement. Where those two boxes sit in the room vs. where you the listener sits, largely determines how your music sounds.

And here’s the sticky part. There are multiple right places, each sounding quite different.

I have watched many an expert set up speakers and each has a completely different approach that results in very different placements. If one watches Wilson Speaker setup expert Peter McGrath work, you’d notice him first walking the empty room clapping his hands and speaking into the air to find the best starting point for the setup. Contrast that with REL Subwoofer owner, John Hunter, who starts with but one channel and spends hours moving it about the room discovering the best place for bass.

At the end of each expert’s process, the sonic results are wonderful yet sonically night and day different.

Now think about your own best efforts at speaker setup. No doubt what you have achieved sounds different indeed from what they would have come up with.

I am in the middle of writing the first in a new series of books called The Audiophile’s GuideThe Stereo offers a detailed step-by-step setup guide for getting the most out of your 2-channel audio system. Following my instructions, there’s no doubt your system will take a leap forward in performance.

But, here’s the thing. My setup methods are different still than experts McGrath and Hunter. And so, yes, once set up, music and its image on the soundstage will be different yet again.

I think the point of this post is to point out just how much difference setup makes.

It’s easy to imagine otherwise.

 

Asheville, Walnut Cove, Biltmore Forrest and Western North Carolina’s Audio and Home Theater specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Palpable sound

When an illusion is real enough it feels as if we might be able to fondle it. Palpable.

That’s what we strive for in our voicings of audio products, sound so real you can imagine touching it. That’s a tough challenge from a design perspective. How do you arm an engineer with the knowledge and tools to craft sound so real it’s touchable?

I think it starts with bass. If you can clear away the phase shifts and filters to get to unfettered bass, then you begin to actually feel the kick of a bass drum in your gut. I know for me that was my first palpable connection. A good thump in the gut from a recorded kick drum.

Over time and experience, you begin ferreting out the small nuanced cues that bring life to music. They happen slowly at first: a bell rings with such veracity you might believe it’s actually in the room. Perhaps a voice so real it’s as if the singer is in the room with you.

The best designers I know have placed this one virtue over just about all others. Make the sound so real it’s as if you can reach out and touch it.

It’s what we strive for and what you likely lust for.

It seems like magic.