AR-2ax: Early Midrange

[Aadams]

43 minutes ago, genek said:

Did you think one sounded better than the other, or were they just "different?"

The video on top sounds more full range and less tinny than the bottom one.  Neither has the sound quality of the streamed version.  I am not sure the phone mic is capturing what we are supposed to hear.  

[ReliaBill Engineer]

22 hours ago, Aadams said:

Why are there two videos presenting the same track from the record?

 

For comparison. How can anyone make a comparison of changes made, using 2 entirely different tracks?

[genek]

Would probably help if you identified what the clips are supposed to be.

[Aadams]

13 minutes ago, ReliaBill Engineer said:

How can anyone make a comparison of changes made, using 2 entirely different tracks?

Both are Chattanooga Choo Choo using an electric bass.  Is it not from the 1965 album image you pasted?   That is the one I streamed for comparison.

[ReliaBill Engineer]

3 hours ago, genek said:

My guess is that one is "before," and the other is "after." But since both videos sound identical, either the perceived improvement is too subtle for phone recordings on computers to capture or there isn't any actual improvement and the exercise has simply resulted in a method of reproducing original sound with a new driver and some crossover mods. 

If you *looked* at the videos, you’d see the stock midranges on one video vs the domes on top of the cabinets in the 2nd video..

And “Thank you!!” The fact that the 2 videos sound so much alike is a complete validation of my efforts!

Very difficult to capture the entire differences using a cell phone. And yes, I know that there will be differences from speaker placement, together on the floor vs on 20” stands 8’ apart. 
 

But my point is that the domes blend so well with the AR tweeter and woofer, and achieve/keep the original sound character! Yet….In the actual room one can hear so much more detail from the recording and so much more “air” to the sound using the domes, vs the colored and directional sound from the paper cones. To capture a better sample from my cell phone, with less room interaction, I toed the speakers in to my standing position between them. Normally I listen with the speakers facing directly forward.

There are no “crossover mods.” Same 6 uF caps and same 16 ohm pots as used with the original AR paper cone mids. Fact is, all I did was clip the green and yellow wires from the paper cone mid and attach them to my dome leads. The paper cone mids are out of the circuit entirely. I used weatherstripping foam gasket that allowed me to pass the wires behind the paper cone mids, yet keep the airtight seal.

[ReliaBill Engineer]

10 minutes ago, Aadams said:

Both are Chattanooga Choo Choo using an electric bass.  Is it not from the 1965 album image you pasted?   That is the one I streamed for comparison.

Both are from the same track on this original 1965 Epic vinyl record. Passed down to me from my parents. No electric bass. Played using the Shure V15V-MR cartridge.

 

 

 

 

 

[Aadams]

45 minutes ago, ReliaBill Engineer said:

If you *looked* at the videos, you’d see the stock midranges on one video vs the domes on top of the cabinets in the 2nd video..

I did look/listen twice.  What you say is not obvious because we never see the stock mids or the dome mids in the first video.  The camera was stationary.  You panned the scene in the second video, showing both speakers with domed mids on top and cone mids in place.

I think I said your first recording sounded better than the second.  They do sound similar but in a low-fi way, not at all what you say you are hearing.  We, on the forum,  have no objective reference from which we can agree or disagree that you have achieved your objective of making an AR2ax sound more like an AR5 or 3a. 

Do you have an AR5 or 3a that you could record side by side with your mod 2ax.

Also, why is this discussion not in Mods and Tweaks?

PS I agree it is not an electric bass but a closely mic ed string bass.

 

 

[genek]

40 minutes ago, Aadams said:

Also, why is this discussion not in Mods and Tweaks?

It may end up there eventually.

I am intrigued by your impression that the first video (which we now know is "before") sounds better than the second ("after").

[ReliaBill Engineer]

2 hours ago, frankmarsi said:

Testing speakers on floors while not observing correct room placement while playing sources of questionable fidelity without indicating equipment powering the whole shebang is hardly qualifying in appraising audio equipment.

 Out of numerous possibilities I sometimes use a vinyl album by “Super-Tramp” called, ‘Crime of the Century’. A forward-rock album which contains plenty of sound variations that can be easily used to judge sound quality of speakers and other components. Many older recordings on almost any format are not recommended as good sources due to advances made in audio recording since. 

FM

 

 

 

 

 

 

630

This isn’t about room placement nor equipment. It’s not a show of someone’s “system.” It’s not about someone’s choice of music media. Suffice it to say, identical equipment was used for both, except for the midrange driver.
 

It's just a comparison of midrange drivers. It’s my attempt to keep the AR sound character, yet use a mid driver that has better dispersion, a less strained sound, and render more detail from the recording. I listen to 95% vinyl sources, so that is what I used for comparison.

In my experience, it is entirely possible to keep the AR sound, but also add more fidelity, and remove some listener fatigue. Those paper cones wear on me after a while. I’m convinced that’s the reason AR added the fiberglass padding.

 

 

 

 

[ReliaBill Engineer]

Not a tweak or mod. Just an attempt at comparison. 
 

There is a story behind that Glenn Miller album.

I can remember my parents having a heated discussion about it. My mother worked for Columbia Records when that album was recorded/mastered/pressed. As the QC Supervisor of the California pressing plant, she raised the issue of a mistake made during recording of “Hello Dolly” with Columbia Executives. The decision was made not to re-record it. Prevailing opinion at that time was that home listeners won’t be able to hear the mistake. In ‘66 my dad’s system wouldn’t reveal it. Stock, these 2ax won’t either. But if you pull up the original soundtrack, at 1:30 into it, you’ll hear one of the trombone players hit the music stand in front of him! That’s why my mom brought that recording home, and my dad was adamant that my mom was making a big deal, risking her job. She didn’t lose her job. She was promoted, and trained the new hires for the new Santa Maria CA pressing plant.

[Aadams]

1 hour ago, genek said:

your impression that the first video (which we now know is "before") sounds better than the second ("after").

I checked my work.  There is a noticeable difference.  I prefer the first to the second.  You can hear the difference using iphone earbuds. You don't need over ear headphones.

PS There is no stand noise in the digital version of this album at 1:30 in Hello Dolly.

[ReliaBill Engineer]

4 hours ago, Aadams said:

I checked my work.  There is a noticeable difference.  I prefer the first to the second.  You can hear the difference using iphone earbuds. You don't need over ear headphones.

PS There is no stand noise in the digital version of this album at 1:30 in Hello Dolly.

Nearfield recording vs further back in the room also makes a difference. It’s a lot like most people preferring the louder of 2 playbacks.
 

As for the Hello Dolly recording, I don’t know which recording you’re listening to. Digital or analog. You didn’t hear it with whatever you’re listening through and from. From the album, it’s actually at 1:14-1:16 primarily in the left channel. I figured you’d hear it on your way into the 1:30 mark. My mother was a perfectionist. It bothered her. 
 

I hear it from the dome mids in my room, and over my headphones, and first heard it from my Polks several years ago. In ‘65-‘66 my dad had the AR-2ax’s and couldn’t hear it. But, he was using a Shure M44C cartridge also. I couldn’t hear it over these stock AR-2ax’s. My dad reminded me of the history associated with that album, at least in our household.

[ReliaBill Engineer]

6 hours ago, genek said:

Would probably help if you identified what the clips are supposed to be.

The titles of the clips are dead give aways:

[Aadams]

14 hours ago, ReliaBill Engineer said:

it’s actually at 1:14-1:16 primarily in the left channel

At 1:16 there is definitely something non-musical going on in the right channel of the streamed version. It doesn't matter.

This thread is drifting. The topic is your mod and its effect on the 2ax. Your stated goal is to move the 2ax sound toward the AR5/3a by replacing a cone with a dome. At this point all we have to go on is your ear.  There are no objective measurements.  There is not even an AR domed 3 way in the house to compare volume matched sound from the same speaker and listening positions when you record with a telephone mic.  We need more than your subjective hearing memory of the "AR sound".

At one point you also wrote, you would be making a mounting plate to a achieve a non destructive fit in the baffle board with the grill installed.  

I have no doubt that what you can hear, and we cannot, is pleasing to you but this is still a rough mod that, without further convincing evidence, we should be talking about in the Mods and Tweaks forum.

[ReliaBill Engineer]

So we’re back in the Mids and Tweaks back alley. 
 

Someone please describe the difference in performance between the paper cone midrange used in the early 2ax, and the dome midrange used in the early 3a….. Descriptions and/or plots and measurements are all fine for answering.

 

 

 

[Aadams]

Pictured below;  the earliest AR3 mid at top left and the first two AR3a mids bottom left and right.

[ReliaBill Engineer]

And performance? Sound, characteristics, plots, tests?

[Aadams]

10 hours ago, ReliaBill Engineer said:

And performance? Sound, characteristics, plots, tests?

Most of what you are asking for is spread across CSP, in the AR library section and in threads of discussion especially involving members, @tysontom@Steve F@RoyC@Carlspeak@kkantor and John O Hanlon.   The best way to search for those threads is Google.

Regarding diffs between the 2ax cone mid and dome mids:

All I actually know is the 3.5" 2ax mid was originally used as a mid/tweeter in an early version of the AR2 series.  Nobody back then seemed to care that a 3.5" speaker would become beamy at 4500hz.  AR added the orange 1" dome to compensate for the beaminess of the mid above 5k, giving the 2ax  a sound character akin to an AR3 and later, with updates, akin to the 3a/5.

The domed mids and tweeters were created by AR in the full range 3way speaker era, to eliminate beaming in the musical freq ranges, well before there were small cone drivers available that could deliver broad uniform sound power at lowest distortion across the middle freq band.

I think your project objective is worthy. You are certainly not the first to think about it.  If you can devise a non destructive, fairly easy modification, using a modern cone or a dome and maybe even a HiVi tweeter to make a 2ax sound much like an AR5/3a/11, it could be blueprint for others to inexpensively resurrect dead or dying 2axs.   You will need some way to tie your results back to an AR source. 

The late member @Zilch , inventor of the Econowave, had a 2ax mod that involved sawing out the upper half of the front baffle and changing the crossover to accept a wave guide and compression driver.  Those discussions are probably in kitchen.

Adams

 

 

 

 

 

[ReliaBill Engineer]

I’m very happy with the sound of these at present, using the original woofer and (super)tweeter, and 4/6 uF capacitors. With the 2” dome mid, it has everything I want. 
 

Surprisingly, I’m having a really tough time sourcing the expanded aluminum guards for the mid. 1/2” x 1/8” diamond opening, 18-20 gauge thickness. I plan to replace the perforated steel guard currently on these domes. Just to keep the AR appearance. I’ve ordered expanded titanium from China. Closest I could find. 
 

Using this dome midrange/tweeter, I found that it, too, needs to be wired just as AR did, out of phase polarity-wise, to get a smooth transition. 
 

The tweeter domes don’t go way out to 20 kHz. But the end result is a hugely pleasing easy, comfortable, effortless sound that I can listen to all day with no regrets. 
 

In my opinion, I’ve done the least amount of molestation to these old girls, while improving the sound, yet keeping the old character. The 16 ohm pots, 6 uF caps, with the new domes and small 0.1 mH smoothing inductor at the dome terminal, helps to control the dome nicely. Whether at very low listening level, or much higher volume, the speakers just sound GOOD to me. No matter the age of recording, nor genre, they are a relaxing, good listen! 
 

My wife prefers listening to her CD collection vs my vinyl collection. Yesterday was her day. Trisha Yearwood, Bonnie Raitt, The Supremes, The Drifters, Patty Loveless, Oak Ridge Boys, etc. She had a good time! 

[genek]

5 hours ago, Aadams said:

The late member @Zilch , inventor of the Econowave, had a 2ax mod that involved sawing out the upper half of the front baffle and changing the crossover to accept a wave guide and compression driver.  Those discussions are probably in kitchen.

As I recall, Zilch was not very happy with his AR-2-based econowave and preferred Advents for his 10" projects. He did econowave a bunch of 8" AR-4s over the years though. Most of those projects were discussed at length in threads over on Audiokarma.

Zilch did participate in this CSP discussion about replacing the AR 3/4" dome tweeter with a  waveguide, not in The Kitchen, but right here in Mods and Tweaks:

 

[ReliaBill Engineer]

The expanded titanium arrived today. Very comparable to the original aluminum.

 

 

 

 

 

[genek]

How will you be shaping the mesh? I expect the titanium will be a bit harder to work than the aluminum was.

[ReliaBill Engineer]

I have a bearing press. I already have the forms made. Using a propane burner to anneal the titanium. This alloy can be softened; otherwise it would crack badly when put through the expanding dies.

[ReliaBill Engineer]

Comparison. Original paper cone mid and the dome.

Original:

 

 

Dome midrange:

 

[ReliaBill Engineer]

I’ve been/am very happy with these ‘65 AR-2ax speakers. They are musical, and just great to listen to. These are now in my workshop in the garage, getting some needed cosmetic attention. Listening to some Bonnie Raitt: 
 

Finished my listening sessions. Now to fully incorporate the much better midrange drivers, while keeping the AR motif.

Auditioning a new cartridge and stylus: