Placement and mounting of early AR bookshelf speakers

[Guest postjob62]

Hello all,

In a previous thread of mine, Tom made it clear that preferable 4x mounting would be flush in a wall or secondarily, surrounded by books on a real bookshelf. Steve F. clarified that the three distances from the woofer to the sidewall, ceiling and backwall should be asymmetrical. These revelations sort of thwarted my intended DIY 26" stands, so I experimented a little tonight moving them around some. First, up to the approximate height my stands would have placed them at. Definitely thinned out the bass, and in my opinion some mids (male voices) sounded worse too. All that was left (given that WAF wouldn't allow flush-wall option and that I have no bookshelves) was to experiment with different heights close to the floor, where they had been residing awaiting their stands. Here's the result: on my thickly carpeted suspended wood floor, these 4x's sounded best by what seemed like a fairly large margin placed on books 6" off the floor- no perceived boominess or muddiness, and even the tweeters sounded fine! (I suppose this is a testimony to the wide-dispersion methodology).

Fellows, please critique me-could this be-small speakers sound good 6" off the floor? Looks like I'll be making my stands 6" tall...

Any advantage, given wide-dispersion, to tilting them back ala Mapleshade Bedrock stands? I tried and didn't think I could tell any difference.

Finally, would 2ax's be likely to respond similarly since they were technically bookshelves as well? And would anyone hazard a guess how a bare concrete floor might impact this mounting?

Regards,

Ed

[charger3834]

Ed,

Tom and Steve really know their theory and you can pretty much take anything they write to the bank. Having said that, only you and your tastes can judge your acoustic enviornment. I would recommend that you continue to experiment for a period of time before you construct anything permanent.

[ar_pro]

Ed -

It's been my experience that vintage AR bookshelf speakers were (and are) very much at home in "real world" situations - that is, rooms with furniture, books, shelves, rugs, etc. - the antithesis of what has now become the required norm for "small enclosure" loudspeakers - ear-level stands filled with depleted uranium-shot, poised on titanium spikes in the middle of a 22'x48' room that's devoid of any seating outside of the teeny-tiny "sweet spot".

It was certainly *not* unusual to find AR-4s or AR-2ax speakers on the floor, a table, or a shelf - they were very adaptable systems, and clearly represent something that has fallen out of favor with current loudspeaker trends.

And maybe that is why they are still well-loved by those in the know.

[Steve F]

>It's been my experience that vintage AR bookshelf speakers

>were (and are) very much at home in "real world" situations -

>that is, rooms with furniture, books, shelves, rugs, etc. -

This, of course, is absolutely correct. The fortuitous aspect of the whole room placement matter is that objects such as sofas, recliners, cabinets--actual furniture found in real rooms--do function to some extent as room "boundaries" from an acoustic standpoint. If there is a heavy-framed, densely-stuffed sofa two feet out from the wall, three feet away from the left speaker, that speaker will "see" the sofa AND the wall as the bass reinforcing surfaces. Since the speaker is a different distance from the sofa than it is to the wall, there's a good example of the acoustically-desireable asymmetry that real rooms present to loudspeakers.

That's why things are never as bad in practice as theory would predict. Your 13 x 13 room with its 87Hz double emphasis "should" sound terrible. It "should" be dominated by a whumpy, bloated, over-emphasis of the upper bass. But it's not. In fact, your 4x's sound pretty darned good, right? Yes, there's a trace of the audible reinforcement/cancellation that changes as you move your head forward and back, but overall, you're still pretty pleased with the sound.

AR's use of the semi-reverberant chamber in their development and testing was an excellent tool for helping predict how their speakers would perform under actual conditions. I'm not aware of any major speaker company that uses such a device today, which is unfortunate. Most "serious" speakers (a rapidly diminishing breed, as iPod and Home Theater-in-a-box replace attentive music listening as a serious hobby) are designed for near-field imaging and therefore are much more placement-sensitive than the 4x and 2ax.

My overall suggestion is to keep the general guidelines we've spoken about in mind when placing your speakers, but don't be a slave to theory. There are lots of other factors at work which operate in your favor and if it sounds good to you, then it's right.

Steve F.

[Guest postjob62]

Good advice from Brad on continuing to experiment before constructing anything permanent. Although these sound pretty good right now at 6" off the carpet, I think I'll try them up to 12" to see if there is any difference. Having said that, there is much to what ar pro says, reinforced by Steve F., including that which is left unsaid between the lines. And that is simply this: the inherent flexibility and adaptability to various environments that they point out with early AR's gives one the freedom to enjoy the music without having to obsess over details. I love that. After all, as observed earlier by previous posters, it's easy to lose sight of the fact that in the end it's all about the music, not just the delivery medium. Others may be more immune, but I myself have a tendency to fall victim to various "tweak" pages and posts, and spend time wondering "what if" that is better spent listening. And although I will admit to using a certain ugly orange speaker cable purchased in the audiophile section of my local home store, I hate the mental process of having to think through and consider these "tweaks".

And these early AR's, because of their flexibility, give me the freedom to forget about the "tweaking". Couple or isolate, complex "sweet spot" calculations and exotic stand theory as pointed out by ar pro- these things are rendered null by the AR's. I mean, really, if these little guys never sounded any better than they do now sitting 6" above carpet on phone books, I would consider myself a lucky person indeed.

I will continue to observe Steve F.'s and Tom's asymmetrical placement tenets, which make sense and are largely understandable even to a non-expert like myself. And if I ever construct real bookshelves, I will give Tom's mounting advice a try. (Short of alien abduction and brainwashing, WAF will forever preclude the in-wall flush mounting).

Meantime, I intend to enjoy.

Regards,

Ed

[soundminded]

Placement is usually a compromise between competing objectives. Decorating esthetics aside, placement at ear level probably gives the best stereophonic effect. This was a recommendation of many manufacturers and users in the 60s. Placement close to walls and floors or ceilings gives bass reinforcement as you near more room boundaries. Corner placement on the floor or ceiling gives the most bass reinforcement and at least one manufacturer today, Audio Note recommends it as the optimal locaton for their speakers (one of which seems to be a lineal decendant of AR4x.) However, this sometimes spreads them too far apart creating a "hole in the middle" or "ping pong stereo" effect. Moving the speakers out into the room tends to de-emphesize the bass and make the treble more prominent. IMO, the best placement is against the short wall about 8 feet apart at ear level. I personally have no objections to using an equalizer to flatten freqeuncy response. One advantage of a tower like AR9 is that of putting the woofers near the room boundaries while keeping the midrange and tweeter drivers at ear level. Maybe that's the best of all possible worlds for real rooms.