12 inch woofer differences.

[harry398]

I own several AR speakers with 12 inch woofers.

What i have noticed is the ar3a with the alnico magnet and cloth surrounds produces lower bass response than my other 12 inch ar speakers.  This includes my ar98ls, ar 50 connoisseur speakers

The connoisseur has a plastic cone woofer.   The 98 is paper with foam surrounds.  The ar3a has the extra dampening material around the center of the cone.

 

So my question is......Is this lower bass response a function of the woofer?  Or is it due to the crossover?

 

They are crossed over at different frequencies, however the ar3a seems to go deeper, and I am curious why.

 

When looking at the spec sheets, its clear the 3a goes lower, but why?  I know they used foam surrounds later on, and the spec did not change.

 

thanks.

 

 

 

[Sonnar]

You have early AR 3a with AR 3's woofer . This woofer has a slightly lower resonance than ferrite , and probably this is the reason why You noticed a deeper bass. I have the old AlNiCo , cloth surround woofer in my four AR 3s , and I think it was a better loudspeaker , but differences are minimal. 

[harry398]

Hello Mr. Sonnar

That could be true, but why does it have lower resonance?   The magnet?  The type of paper? the added dampening?

 

I have just recapped my ar3a with some NPE caps with some bypassing on the mid and tweeter circuit.   Sound has improved, even with these 50 year old tweeters that are tired.

cleaned the pots (which I previously soaked with WD40, and were clean,but function wasnt perfect), I just lightly sanded them and applied dielectric grease.  wala...trick done.

Funny thing?  The woofer is outputting better too?!?!  This speaker produces some really good low frequencies, and I am talking at low volumes.   Its something else.

So I am curious,   WHY?

[genek]

My guess is that your woofer seal might have been leaking before you opened the box up and you fixed that when you closed it up.

[harry398]

NOPE.

was sealed before and after.  I always check that.

another thing that may thing that have changed is placement of stuffing....but this still doesnt answer my question WHY the ar3a produces lower bass frequencies.

I will say the ar3a seals real nice...but the 98 doesnt seal as tight...

[genek]

Sorry, I thought you meant that bass improved after the recap. Which wouldn't make any sense.

[harry398]

I am also saying, the Bass Improved after the recap, for whatever reason.

moving the stuffing?

It was most definitely sealed before, and sealed again.  

2 changes....recap and move stuffing.   I think I stuffed more up top near tweeter, but that stuff is all clumpy......who knows where it moves.

I guess if I really get interested, I could swap this Alnico into the ar50 and see what happens.   I think the plastic woofer sounds different, as well as not going as deep, but i am not sure about it.

What I do know, is this Ugly Alnico with its extra dampening ring goes deep.  

The ar11 "supposibly" goes lower, but that did not have this woofer.  

So thats why i am wondering what is the True reason for lower freq response.

[RoyC]

1 hour ago, harry398 said:

I am also saying, the Bass Improved after the recap, for whatever reason.

moving the stuffing?

It was most definitely sealed before, and sealed again.  

2 changes....recap and move stuffing.   I think I stuffed more up top near tweeter, but that stuff is all clumpy......who knows where it moves.

I guess if I really get interested, I could swap this Alnico into the ar50 and see what happens.   I think the plastic woofer sounds different, as well as not going as deep, but i am not sure about it.

What I do know, is this Ugly Alnico with its extra dampening ring goes deep.  

The ar11 "supposibly" goes lower, but that did not have this woofer.  

So thats why i am wondering what is the True reason for lower freq response.

ALL of the earlier 12 inch woofers, including the ferrite magnet/foam surround version are more compliant (softer suspensions) and work best in the 3a cabinet. The suspension, and greater cone mass, are the primary reasons they produce more bass response in a cabinet the size of the 3a. The trade-offs are lower sensitivity and lower power handling. Later AR woofers, especially the plastic cone versions, have stiffer suspensions and lighter cones. These are much more sensitive, and extend further up into the midrange frequencies. They can handle more power than the early woofers, and function better in larger cabinets.

The AR-11 era woofer does not provide deeper bass response. It is the same woofer used in later AR-3a's, in essentially the same size cabinet.

There is also a subjective reason the bass response seems greater in 3a's with original woofers. The design of later models placed greater emphasis on higher frequencies.

Your re-cap most likely altered the performance of the parallel 150uf woofer capacitor. Assuming you used the same amount and type, as you mentioned, stuffing placement could have had some effect as well.

Roy

[harry398]

6 hours ago, RoyC said:

ALL of the earlier 12 inch woofers, including the ferrite magnet/foam surround version are more compliant (softer suspensions) and work best in the 3a cabinet. The suspension, and greater cone mass, are the primary reasons they produce more bass response in a cabinet the size of the 3a. The trade-offs are lower sensitivity and lower power handling. Later AR woofers, especially the plastic cone versions, have stiffer suspensions and lighter cones. These are much more sensitive, and extend further up into the midrange frequencies. They can handle more power than the early woofers, and function better in larger cabinets.

The AR-11 era woofer does not provide deeper bass response. It is the same woofer used in later AR-3a's, in essentially the same size cabinet.

There is also a subjective reason the bass response seems greater in 3a's with original woofers. The design of later models placed greater emphasis on higher frequencies.

Your re-cap most likely altered the performance of the parallel 150uf woofer capacitor. Assuming you used the same amount and type, as you mentioned, stuffing placement could have had some effect as well.

Roy

Thank you for the detailed response Roy.

It was informative and makes sense.

 

 

[Pete B]