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AR-3a position


jam1n

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I've just finished restoring a pair of AR-3a's and I'm interested to know how people find they get the best sound from them. I've read a few comments here and there on the forum but couldn't find a specific thread on the subject. 
 
So, how do you find the AR-3a to sound its best? 
  •  Against the wall or out in the room? 
  • Toed in or parallel?
  • Tipped back slightly or level?
 
I know some people say they should really be on their sides but that's not an option for me at the moment due to the space. I have mine on home made stands, tipped back about five degrees.
 
I had been enjoying them toed in, a couple of feet out from the wall but since rebuilding the crossovers, I'm finding that I like them better parallel, back against the wall. It seems to open up the sound stage in every direction for a much more immersive listening experience.
 
What works best for you?
 
Ben
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I have mine about a foot from the back wall , and about 3 feet from the side walls. They are vertical,  on stands about 2 feet off the floor. No toe in.

I've tried them pretty much every way possible in my room(higher and lower off the floor, closer and further from walls, toed and not, horizontally and vertically) and have found the present set up to sound best. That said, they have never sounded anything but great, and the differences with placement in my smallish room have been minimal.

Ultimately experimenting is your best friend. There is no wrong or right, only what sounds best to you.

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2 hours ago, samberger0357 said:

I have mine about a foot from the back wall , and about 3 feet from the side walls. They are vertical,  on stands about 2 feet off the floor.

Mine are very similar to Samberger's but toed in about 15 degrees.   If you installed lpads or new style pots you have an opportunity to exactly match the output of the mids, which can make a big difference, but is not as easy as it might seem on first impression. 

Adams

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The dome mids and tweeters are designed to produce semi-hemipherical emission, so if they are working properly parallel should work best. If you have replaced the tweeters with HiVi units you have somewhat "beamier" highs and toeing in a bit may sound better.

The ideal wall placement is actually set into the wall, as in a bookcase surrounded by books, but the closest I ever got to that with mine was in one of those old "entertainment center" wall units. They're now on stands about six inches from a wall and some windows.

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Thanks everyone.

19 hours ago, genek said:

The ideal wall placement is actually set into the wall, as in a bookcase surrounded by books,

Thanks genek. Mine are now in alcoves, either side of a fireplace, which comes close to this, on one side at least. The Roy Allison articles help to explain why this seems to help.

6 hours ago, Aadams said:

These illustrations are from the Roy Allison paper regarding the effects of room boundaries on woofer placement.

Thanks Aaadams!

6 hours ago, Giorgio AR said:

this document is a great gift from you and Roy!

Giorgio, I found the full Roy Allison paper online here and (of course!) in the CSP library here. Interesting reading but a bit too technical for me at points. I also found this article, which is a bit more accessible. It gives a simplified overview of the conclusions from his research and describes a computer program he made to model the effects of room placement on output. I also found the program itself in the CSP library to download here.😄

If I understood it correctly, the conclusion of these papers was that the best placement (if not recessed) is where the distance from the rear wall, nearest side wall and the floor are as different as possible, which also chimes with what samberger said:

22 hours ago, samberger0357 said:

I have mine about a foot from the back wall , and about 3 feet from the side walls. They are vertical,  on stands about 2 feet off the floor.

Mine are now backed up against one wall, recessed in an alcove, about a foot off the floor and two feet from the side walls. Seems to work but it’s nice to understand a bit more about why.

The one thing I’d like to understand better is why I seem to prefer them tilted backwards. I think I read something PeteB said on the forum about this at some point but I’ve not been able find it again.

20 hours ago, Aadams said:

If you installed lpads or new style pots you have an opportunity to exactly match the output of the mids, which can make a big difference, but is not as easy as it might seem on first impression.

I did. Sounds like fun! Any advice for how best to accomplish it?

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1 hour ago, jam1n said:

Any advice for how best to accomplish it?

You must isolate the mids from the woofers.  These instructions use a graphic equalizer.  If you don't use an equalizer then you can disconnect the jumper wire that connects the #2 terminal to the "T" terminal and temporarily move the speaker wire from  #2 to "T". 

The AR classics with potentiometer or lpad attenuators, as opposed to later series with stepped or no attenuation settings, are difficult to balance.  If you want to hear a classic at it’s absolute best the attenuators must be adjusted to bring the corresponding drivers of the stereo pair into exact loudness balance.  In the case of the 3a and 5 the mid-range attenuator is the predominate factor in determining whether the sound is focused and centered as opposed to sounding vaguely centered and with a shifting soundstage.

I have found an easier way to balance attenuators that employs a 10 band equalizer.

For a 3a or 5 set the sliders to full minimum on every band except the 2k band which should be set to maximum.  This provides max emphasis at 2k which is in the middle of the mid range driver bandwidth. 

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1. Assuming you already have the attenuators at a loudness setting that pleases you:

2. At normal or lower volume, play a mono recording with vocals, I like Glenn Miller or early Beatles for this, and listen within 3-4 feet to judge if the image is centered between the speakers.  Toe them in if you can.  Adjust the attenuators until the image is centered in the near field or at the listening position or both. 

3. Return the equalizer to its normal setting and reposition the speakers. You are done.

Adams

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20 hours ago, jam1n said:

The one thing I’d like to understand better is why I seem to prefer them tilted backwards. 

A slight upward tilt will project sound a bit toward the ceiling. If you have standard 8ft high flat ceilings, this will result in a bit more reflection off the ceiling that may be changing the reverberant field more to your liking.

If you have 16ft high, vaulted ceilings the effect will be negligible and the difference in sound is probably mostly in your imagination.

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Just got a set of these JBL JS-120 steel speaker stands yesterday. They were designed for Century 100's, but are a perfect fit for my AR3a's. I think they have a 5 degree rake.  Set them up in another room today and have been listening off and on all day. I think they point the tweeters and midranges more toward my listing position than the previous flat stands. 

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