AR 3 toe in or not?

[samberger0357]

Can't seem to find much online. Has there ever been an "official" recommendation regarding positioning the 3's in regard to toe in? Mine are toe'd in a bit, and I've experimented, but would like to hear what others are doing with their 3's/3a's, and if Mr. Villchur ever provided an opinion.

[Sonnar]

You mean convergency toward listener? 

[samberger0357]

Yes. 

 

 

[genek]

Toeing in does a great job of completely collapsing the reverberant field that the speakers' dome mids and tweeters are designed to create.

[samberger0357]

Did not know that. Thanks. 

[der]

I had never heard that either.

der

[tysontom]

 

6 hours ago, samberger0357 said:

Can't seem to find much online. Has there ever been an "official" recommendation regarding positioning the 3's in regard to toe in? Mine are toe'd in a bit, and I've experimented, but would like to hear what others are doing with their 3's/3a's, and if Mr. Villchur ever provided an opinion.

AR never recommended "toeing-in" AR-3s or AR-3as or any AR speakers, mainly because these were designed to produce a widely dispersed, enveloping sound field.  Some speakers are very directional, and these benefit somewhat by having them pointed in the direction of the listener, but this would not be the case for an AR-3 or AR-3a.  Usually, the speakers that are very directional (poor dispersion throughout the midrange and treble frequencies) will sound poor back in the reverberant sound field because the "power response," or the combined acoustic-power output into the room, is greatly diminished.  What you should hear in a room (unless you are at point-blank range) is a combination of direct and reflected energy (much more of the latter), and the better the dispersion, the smoother and more "spacious" (and realistic) the sound will be.  On the other hand, directional speakers lack the 3-dimensional sound of wide-dispersion speakers, and directional speakers will sound dull well back in a room because of the attenuated reflected energy. 

--Tom Tyson

[samberger0357]

Tom thanks! Exactly what I was looking for. 

[Carlspeak]

What TT wrote is true. However, the final arbiter of what sounds good to you is YOU. Try experimenting with different degrees of toe in or none and judge for yourself. I suggest this only because your room conditions are a huge variable in how the sound is dispersed/absorbed, etc.  

Go ahead, experiment. Have fun. It's all part of the hobby!

[samberger0357]

Definately. Always. Was really looking to Tom, and others, for a base point, which is exactly what I got. 

 

Thanks.

[der]

Thanks Tom. After pondering this I believe I may have known this at one time when I first got involved with high quality reproduction and AR. Life kind of got in the way of the hobby and I've forgotten a lot.  Could be age related, I seem to have forgotten a few other things as well.  I definitely am going to experiment a bit.

der

 

[stan461]

39 minutes ago, Carlspeak said:

What TT wrote is true. However, the final arbiter of what sounds good to you is YOU. Try experimenting with different degrees of toe in or none and judge for yourself. I suggest this only because your room conditions are a huge variable in how the sound is dispersed/absorbed, etc.  

Go ahead, experiment. Have fun. It's all part of the hobby!

hear! hear!

Recommendations are a good starting point

[Carlspeak]

After thinking in the shower about what I wrote, I thought I should expand on the suggestion at bit with some thoughts on how to go about doing those toe in experiments.

First, pick just a few reference tracks to listen to. Music you are very familiar with. Then start with an orderly transition of toe in movement from none to pointing directly at you. Hopefully, you can do 3 or 4 different toe in positions in addition to none and full toe in. 

Most importantly, at each position, live with that setting for a week or two. Do some critical listening every few days and take notes in a journal. You might want to create some measures of sound quality to list and compare at the end of your journey.

[samberger0357]

Thanks again. I tend to do move stuff around a lot anyway, and speaker tweaking is a simple one. That said, having them shoot straight out into the room sounds very nice at the moment. 

[Steve F]

A few thoughts here: First, as Tom and Genek said, the AR domes were designed to produce very wide dispersion and a large amount of reflected energy, meaning that AR expected listeners to be seated in the far field so ‘toe-in’ for near-field imaging purposes wouldn’t be necessary.

 

Also, in the 1960’s, AR envisioned their speakers to be true bookshelf speakers, as shown in this picture from their 1971-1972 full-line brochure. Mounted in a bookshelf, the speakers would not be physically able to be toed in. So that’s pretty much the ‘proof,’ so to speak, about how AR felt about toe-in.

 

There is the thought that a speaker’s best FR will be 1m on-axis, so the appropriate toe-in would place the listener (at least the one in the ‘money seat’) on-axis of both stereo speakers, so ostensibly, he’d hear the speakers’ best response as first-arrival sound, a few milliseconds before room reflections kicked in.

 

This didn’t matter with the 1950’s-1970’s AR (Classics and ADDs), because their haphazard driver placement and horrendous diffraction (in the Classics) meant their on-axis FR wasn’t their best performance. AR barely measured 1m on-axis system performance, preferring instead individual driver curves (to verify accurate response within their band) and full-system far-field energy curves, which is all AR felt really mattered at that point in speaker design history.

 

So I’d agree that toe-in with the 3, 3a or 5 is unnecessary. By the time AR did the Verticals in 1978, it was a different story. The 9, 90, 91 and 92 had exemplary near-field frequency response and terrific far-field energy response. AR finally realized that the two were not mutually exclusive. For the Verticals, I’d say experiment a bit. I have my 9’s toed-in very slightly, but my 3a’s (in another room) are pointing straight ahead.

 

BTW, a quick comment, not meant as criticism, just an observation. Samberger’s room is so nicely decorated—beautiful drapes, a magnificent fireplace, rich-looking hardwood floors. Those 3’s on a stand, with speaker wire draped unceremoniously all over the place, look so homely, out of place and unharmonious with the décor of the room. I know we all love our speakers, but this room is absolutely ruined by those 3’s. The 3a’s buried in a bookshelf, as shown in the attached AR brochure pic, is pretty much the only way they look acceptable in the “public area” (non ”man-cave” area) of a home.

 

 

 

Steve F.

 

[samberger0357]

First thank you Steve for your comments re: toe in. Excellent information.

 

As for your comments regarding my room and speakers, I shan't show the missus Actually, I"m not sure if you're being serious or not. This room is truly a "living" room that has seen 2 dogs and several cats, not to mention 2 working(and kinda sloppy) adults, a child from birth to 18, and all kinds of audio including very large speakers, cabinets, etc, amongst it's adventures. The scars of "living" are certainly there, but perhaps they don't come out in the picture to the uninitiated. I actually think the speakers class up the joint some, although your comments regarding speaker wire is correct. One day I'll get around to hiding it. 

 

Or not. 

[Steve F]

Am I being serious?

Tongue firmly planted in cheek. Where it's been painfully bitten oh-so-many times in the past.

Steve F.

[samberger0357]

I figured. Not only did you produce articulate and helpful information, but a very big chuckle. Thanks!

[der]

Day two of re-positioning my 3a with no toe in.  I'm forced to have my speakers rather far apart due to the presence of a 8 foot bay window in my listening room. My speakers are on either side of the window.  I found I've had to make some level adjustments to the mid and tweeter pots to balance the speakers.  I've been playing records that I'm very familiar with.  I can't find a real downside with this arrangement.  The sound stage is wider now and there's no center hole.  Imaging is very good as well.  I think I'll leave them like this for awhile.

[tysontom]

On 4/13/2016 at 4:12 PM, Steve F said:

A few thoughts here: First, as Tom and Genek said, the AR domes were designed to produce very wide dispersion and a large amount of reflected energy, meaning that AR expected listeners to be seated in the far field so ‘toe-in’ for near-field imaging purposes wouldn’t be necessary.

 

Also, in the 1960’s, AR envisioned their speakers to be true bookshelf speakers, as shown in this picture from their 1971-1972 full-line brochure. Mounted in a bookshelf, the speakers would not be physically able to be toed in. So that’s pretty much the ‘proof,’ so to speak, about how AR felt about toe-in.

 

There is the thought that a speaker’s best FR will be 1m on-axis, so the appropriate toe-in would place the listener (at least the one in the ‘money seat’) on-axis of both stereo speakers, so ostensibly, he’d hear the speakers’ best response as first-arrival sound, a few milliseconds before room reflections kicked in.

 

This didn’t matter with the 1950’s-1970’s AR (Classics and ADDs), because their haphazard driver placement and horrendous diffraction (in the Classics) meant their on-axis FR wasn’t their best performance. AR barely measured 1m on-axis system performance, preferring instead individual driver curves (to verify accurate response within their band) and full-system far-field energy curves, which is all AR felt really mattered at that point in speaker design history.

 

So I’d agree that toe-in with the 3, 3a or 5 is unnecessary. By the time AR did the Verticals in 1978, it was a different story. The 9, 90, 91 and 92 had exemplary near-field frequency response and terrific far-field energy response. AR finally realized that the two were not mutually exclusive. For the Verticals, I’d say experiment a bit. I have my 9’s toed-in very slightly, but my 3a’s (in another room) are pointing straight ahead.

 

BTW, a quick comment, not meant as criticism, just an observation. Samberger’s room is so nicely decorated—beautiful drapes, a magnificent fireplace, rich-looking hardwood floors. Those 3’s on a stand, with speaker wire draped unceremoniously all over the place, look so homely, out of place and unharmonious with the décor of the room. I know we all love our speakers, but this room is absolutely ruined by those 3’s. The 3a’s buried in a bookshelf, as shown in the attached AR brochure pic, is pretty much the only way they look acceptable in the “public area” (non ”man-cave” area) of a home.

 

 

 

Steve F.

 

Bookshelf mounting for the AR-3/AR-3a is certainly an ideal way to do it if possible.  It most importantly avoids the so-called "Allison Effect," or boundary dip where the woofer's output at certain frequencies (usually in the 300 Hz range for the 3a) will tend to bounce off the floor and back wall and come back and "cancel" the bass energy at that frequency.  It's not nearly as serious as some would have you believe, and many manufacturers have simply ignored it for many years, but it is definitely a measurable part of the frequency response in the low frequencies.  Mounted flush in a bookshelf or flush in a wall, etc., gives a nearly ideal, flat output as the speaker faces a true 180-degree (2 pi steradians) solid angle, without any dips or peaks.  Since the AR-3/3a woofer is literally flat within 1.5 dB from 38-1000 Hz, the low frequency is very uniform when a speaker is placed in a bookshelf.  But is the dip that audible?  It is audible, but you usually have to be listening to white noise or have a A-B comparison to realize the difference in many cases.  Some Allison audiophiles insist that the "dip" is extremely important, but there are other opinions.

With the dispersion of the AR-3 and AR-3a (and even more so with something like the AR-LST), once you are about 3-4 feet back from the speaker, the bulk of the energy that reaches your ears will be reflected, not direct.  In other words, if you want to listen to just the speaker itself, as though anechoic, you have to be right in front of it within a foot or so, and you could then toe-in the speakers.  Otherwise, it is not necessary.  

My earlier AR-3a bookshelf mounting (below) was good, but I had to add more books around the speakers to the sides and below, to make it more of a flush setup.

--Tom Tyson

 

 

[samberger0357]

Interesting. So theoretically, would there be any advantage placing the AR3's against a wall while  on floor stands  get the same, flat output or does having them vertical and without  all four sides enclosed cancel that effect out?

[tysontom]

The idea is to have the front face of the speaker flush with the wall.  If on stands, they should be back within a few inches of the front wall anyway, but the depth of the cabinet, front-to-back, will cause sound waves at certain frequencies to travel around the sides and bottom of the speaker, bounce back out-of-phase with the front wave, causing a cancellation (or "dip") at certain frequencies.  Again, there is argument as to how much this is audible, but it's there nevertheless.  This is what the Allison speakers were all about.  Flush in a bookshelf, however, there is none of that.  You can put them on the floor, and that will cancel the reflection off the bottom side of the cabinet, reducing the "dip" effect, but an AR-3 or AR-3a will sound boomy or tubby if placed directly on the floor, so this is never a good placement.  On stands, close to the front wall, is second best to flush-mounting.  Typically, one speaker on a stand (the left or right channel) should be somewhat closer to a side wall than the other, and the speakers should be a minimum of 12-15" inches off the floor.

This so-called "Allison Dip" has actually been known for many years, but Roy Allison and Robert Berkovitz actually quantified and defined the effect during his test of many AR-3as used in homes (and the AR Rooms) around the Boston area, and Allison and Robert Berkovitz wrote a brilliant paper describing this in several papers, the most notable and detailed was the October, 1970 JAES paper, "The Sound Field in Home Listening Rooms."  This is a long detailed paper with millions of graphs and representations, but it is worthwhile to read at some point.

Top picture is actually an AR-3 being measured facing into a 180-degree solid angle.  Note the lack of any interference or reflection in the bass output right down to the resonance frequency, shown in the measurement of that speaker.  This is considered an exceptionally uniform, flat response for a woofer.

--Tom Tyson  

 

[samberger0357]

Tom thanks again. Very insightful. 

When you say "The idea is to have the front face of the speaker flush with the wall.  If on stands, they should be back within a few inches of the front wall anyway " I think I understand you, but to clarify, to me the front face of the speaker is the side with the grill on it. And the front wall is the wall that the grill is pointing at. In my room, the back of the speaker(the side that speaker terminals are on) are a few inches from the wall. Is that that you refer to as the  front wall?

 

[tysontom]

It is a bit confusing, but the front wall is the wall where the speakers are located, facing towards you.  The back wall is at the opposite end of the room from the speakers.  The front face of the speaker is the grill side, but it looks at the "back" wall.  I guess it is a matter of interpretation, but that's generally the correct definition.  So, yes, the back of the speaker should be a few inches from that wall.  It is not a critical dimension, but the AR-3a, and most AR speakers, are designed to be placed close to the "front" wall.  Sorry that it is confusing, but I think you understand what I'm saying.

--Tom Tyson

 

[Carlspeak]

BOOKSHELF VS FREE STANDING BASS BOOST

The in-ground test AR did is called a 2 pi (180 deg.) test by audio techs. The recorded FR shows roll off at the low end at about 50 hz which is about 10 hz above box resonance. My FR tests are done with the speaker on a stand, out away from walls in a room and thus those results are called 4 pi. (360 deg). I've generally found the roll off to start at a higher level, around 80 hz. with the 3a's I've restored. In fact, most speakers I've meas. this way have roll offs approx. twice cabinet resonance. Consequently, that bookshelf (i.e. flush in-wall mounting) 30 hz bass boost is certainly significant.

What I've written above is pretty common knowledge now-a-days (i.e. placing a speaker close to a wall extends bass response). Allison took advantage of this in many of his designs that employed smaller woofers (mostly 8 inches) to help boost the bass from those relatively smaller drivers.

So, kudos to those AR engineers and marketers for promoting bookshelf applications. Even their AR4x literature depicts them on a book shelf behind Judy Collins sitting at a desk, IIRC.