Would this work to improve AR9 bass?

[Guest retreatwi]

I finally have the drivers refoamed and installed in my AR9s. I have had them for 10 months and finally listened to them last night for the first time. Granted, I know I don't have enough power to run them properly, but I had them running on a Kenwood KM-X1 amp that has 100 watts per channel. My first impression was that they sounded great, but I was expecting a lot more bass.

Since I don't have a large amp to run them, I got to thinking if this would work. Could I biamp them using the same amp? Meaning, can I hook the upper range to the front section of the amp, and hook the woofers to the sub woofer part of the amp or rear part of the amp?

Any other suggestions for better bass would be appreciated.

thanks

[onplane]

I finally have the drivers refoamed and installed in my AR9s. I have had them for 10 months and finally listened to them last night for the first time. Granted, I know I don't have enough power to run them properly, but I had them running on a Kenwood KM-X1 amp that has 100 watts per channel. My first impression was that they sounded great, but I was expecting a lot more bass.

Since I don't have a large amp to run them, I got to thinking if this would work. Could I biamp them using the same amp? Meaning, can I hook the upper range to the front section of the amp, and hook the woofers to the sub woofer part of the amp or rear part of the amp?

Yes, you can do that and it will provide more power. Separating the high current draw woofers from the other drivers can only help.

Your Kenwood has 6 identical 100 wpc amps (of which you are using only two). I would wire the front outputs to the AR-9 woofers and the surround outputs to the mids/tweeters.

You then have to tell your Kenwood that you have 4 speakers. Next, you must select STEREO ALL. That is, you want the left and right signal to be applied to all of the amps and NO SIGNAL PROCESSING.

This should get you clearer and cleaner high frequencies. Let us know how this works.

Finally, if your Kenwood allows you to adjust the frequency range of each amp, you might try cutting the low frequencies on the mid/tweeter amp as much as you can. This will gain headroom in that amp and potentially reduce IM distortion.

Regards,

Jerry

[Guest retreatwi]

Wow! You sure know your stuff. I didn't expect such a detailed response. I will give this a try this weekend and report back. thanks a lot!

[onplane]

Wow! You sure know your stuff. I didn't expect such a detailed response. I will give this a try this weekend and report back. thanks a lot!

Wish you the best of luck on your "experiement".

For the record the technical term for this is "passive biamping". I "experimented" with this technique 4 years ago on my AR-3a's.

In short, ... they have been passively bi-amped ever since.

Regards,

Jerry

[ar_pro]

I'm concerned that something is wrong with your speakers.

Assuming that we're discussing the 1980-era Teledyne AR-9, and not the later AR system that carries the same model number, your observation that the speaker is light in the bass is unusual - a properly-functioning 9 is anything, but bass-shy. It's LF capabilites surpass any other speaker that AR ever built.

There are variables, though - like what is your expectation? If you're looking for thumping, car-audio bass, you won't find it in the 9, since that's more of a special-effect than accurate reproduction.

Room placement and program material are other factors that will come into play - the 9s require a decent-sized room for best LF reproduction, and the manual covers placement pretty extensively.

That said, I've heard the 9 with many amplifiers in the 100-watt range, in many different rooms, and it's just not bass-shy.

I'd be concerned that (at least) the woofers aren't properly connected, and double-check their wiring. The refoaming is another issue - were the correct surrounds used, and properly installed?

These factors will have a profound impact on the performance of your speakers.

The system is set up to biamp, but that's hardly the issue, here - hooking a separate 100 watt amplifier channel to the upper part of your speaker won't give you more bass.

[soundminded]

This may not be a good amplifier for this speaker. The link below is for a pdf file of the owners manual. Note the warning on page 7 not to connect this amplifier to a load of under 6 ohms. Most HT receivers and amplifiers are not suited 12" AR speaker systems because they are nominally 4 ohms and at some frequencies are even less.

http://www.scribd.com/doc/3279607/Kenwood-...-Manual-English

You can improve the situation by installing a resistor in series with the speaker. Try a 2 ohm 30 or 40 watt. If that doesn't work, try two of them in series. It will waste power but will raise the impedence the amplifier sees and it may be more suitable.

You should be certain that the speakers are well sealed. This speaker enclosure MUST be air tight to function properly. This is relatively easy to check with AR9 because it has 2 woofers. Remove the grills from the woofers and gently push one in slightly while watching the other. The other one should pop out immediately and stay out until you release the one you pushed in. Do not push hard and be extremely cautious so that you do not damage it. If the speaker does not pop out immediately or returns before you have let the one you pushed go, you have an air leak. Be certain that the foam gasket is in tact and installed between the enclosure and the speaker and that all of the screws are tight. If the gasket is damaged or missing, you can buy replacement material cheaply from Parts Express.

AR9 is very sensitive to placement. It should be directly against the back wall and at least 2 feet from the side wall. With room on both sides. Be certain the speakers are in phase. If they are out of phase with each other, there will be substantial cancellation of bass. Try reversing the leads to one channel. BTW, check to see that the internal wiring is correct. The red wires should be connected to the positive terminals on both speakers.

Assuming there is nothing wrong with the speakers or the amplifier, room acoustics may be your problem. It happens to be mine. The room cutoff frequency is 1090 divided by the longest dimension of your room. Below that frequency, bass will fall off rapidly no matter what the response of the speaker. To compensate, a graphic equalizer has worked well for me. When properly adjusted, my AR9s can literally shake my house and break every one of 28 panes of glass in my listening room. I once came within a hairs breath of doing just that by accident. And they can thump thump with the best of any car stereo speaker if that is what you really want out of them.

[Guest retreatwi]

I feel pretty stupid. After looking closely at everything, I found that I didn't have the speaker wire connected properly. Once I got the wires right, there is plenty of bass. Plenty. They sound fantastic. I don't have a 4 ohm amp, but am using an NAD 7140 that has a 4 ohm switch.

All of my gear is from thrift stores, garage sales, and craigs list. I bought the AR9's from a person on Craigs list. I can't get over how good these speakers sound. I could only turn the volume knob up to about 9 o'clock (probably 3 out of 10) before things started shaking. Again, the bass is very good. Outstanding. These are truly the best speakers I have ever heard.

[onplane]

Those AR-9's are highly regarded speakers and bass is one of their strong points.

Certainly is great that you found the wiring error.

Your NAD is a 40 wpc amp, so as long as play at moderate levels everything should be fine.

I would not give up on the Kenwood, however. Once you "split the load" as we discussed, I think you'll be fine. With those HT amps you can tell when they are working hard by watching the fan speed. Again, while the Kenwood has more power, you really don't want to push either amp with those speakers.

The other advantage you get with using the front and surround amps is that you can adjust power going to each speaker half to suit your likes, and room. The switches on the AR-9's allow you to cut back on the mids/tweeters, but what if your room is full of sound absorbing material and you want the speakers just a tad "brighter".

Regards,

Jerry

[ar_pro]

Now that he has properly connected his speakers, retreatwi just needs a stable amplifier with a decent amount of power - strapping a couple of marginal HT channels in the AR-9's bi-amp mode isn't going to solve anything.

And as far as Jerry's advice to "adjust power going to each speaker half to suit your likes, and room", the AR-9 manual specifically advises AGAINST inputs to the two sections being at different levels, declaring it to be "a situation which will severely impair the intrinsic balance of the speaker".

[onplane]

Now that he has properly connected his speakers, retreatwi just needs a stable amplifier with a decent amount of power - strapping a couple of marginal HT channels in the AR-9's bi-amp mode isn't going to solve anything.

And as far as Jerry's advice to "adjust power going to each speaker half to suit your likes, and room", the AR-9 manual specifically advises AGAINST inputs to the two sections being at different levels, declaring it to be "a situation which will severely impair the intrinsic balance of the speaker".

Yep, I strongly encourage altering the "intrinsic balance" of the speakers to suit your needs/room/likes. AR allows you to alter the "intrinsic balance" with their switches. That is, you can cut the mids/tweeters -3 and -6 db.

Hmmmm, there must be something magical or mystical about -3db and -6db????

Obviously if you cut -2db or heavens +2db you will end up in the abyss.

By all means don't be fearful of trying things just because some "purist" tells you that doing so will result in damnation.

Regards,

Jerry

PS: the comments quoted in the AR manual deal with "dissimilar amplifiers". Here we have 6 identical amps. Further, you can usually adjust amp output in these types of amps in 1db increments.

[ar_pro]

The AR-9 manual could not be more clear - it advises against applying differing levels of amplification to the two sections - a condition that would be encountered by using dissimilar amplifiers, or by actively varying the levels, which is exactly what you suggested retreatwi try with his speakers. The point is, that the designers of the AR-9 thought this to be a very undesirable circumstance, and specifically caution against it in the manual.

But maybe you have some special insight that the manual's missing - how are your AR-9's connected, Jerry?

[onplane]

The AR-9 manual could not be more clear - it advises against applying differing levels of amplification to the two sections - a condition that would be encountered by using dissimilar amplifiers, or by actively varying the levels, which is exactly what you suggested retreatwi try with his speakers. The point is, that the designers of the AR-9 thought this to be a very undesirable circumstance, and specifically caution against it in the manual.

But maybe you have some special insight that the manual's missing - how are your AR-9's connected, Jerry?

Actually the manual is kind of interesting and I'd characterize it as anything, but clear. It tells you to set the switches at “0” if you habitually play at loud levels to avoid excessive heat. Isn’t varying power the ideal solution to this problem?? I mean, it’s a heck of a lot better than dissipating power in resistors.

Finally, surprise, surprise, the manual says you can adjust the relative balance between the upper range and the woofers by varying the volume controls on the amps. It says to do this as a last resort and in conjunction with the switches (which you shouldn’t use if you listen loud habitually).

Think about it, if the tweeters are weak (as Zilch recently confirmed in his measurements of the 3a) isn’t varying power the ideal solution? That is, cut the mids by 3db (by means of the switches) and then apply 3 db more in the upper amp.

This is exactly what I do on my 3a’s (see below for details):

http://www.classicspeakerpages.net/IP.Boar...?showtopic=4952

Regards,

Jerry

[ar_pro]

AR suggests setting the level controls to zero dB to avoid excessive heating of the resistive elements when used with a very high powered amplifier, and at habitually high listening levels.

This is an extreme circumstance that has never been encountered in my experience with the AR-9, and one that I've never heard reported by any other owner.

The fact that the manual is detailed enough to touch on this extreme use of the loudspeaker, just goes to show how thorough, authoritative, and clearly-written it truly is.

It does beg the question, however - based upon your clever solution for a problem which has not been reported by other users, why don't you tell us of your practical experience with the AR-9?

Have you ever actually owned a pair?

Have you ever restored a pair?

Have you ever even heard a pair?

[Diamonds&Rust]

I feel pretty stupid. After looking closely at everything, I found that I didn't have the speaker wire connected properly. Once I got the wires right, there is plenty of bass. Plenty. They sound fantastic. I don't have a 4 ohm amp, but am using an NAD 7140 that has a 4 ohm switch.

All of my gear is from thrift stores, garage sales, and craigs list. I bought the AR9's from a person on Craigs list. I can't get over how good these speakers sound. I could only turn the volume knob up to about 9 o'clock (probably 3 out of 10) before things started shaking. Again, the bass is very good. Outstanding. These are truly the best speakers I have ever heard.

When you can, put a monster of an amplifier on them. It's a "next level" experience.

I ran mine on 160w/channel Kenwood receiver, a 270w/channel Pioneer, a 60w/channel Yamaha, a 125w/channel Pioneer, a 500w/channel ESS professional amp, and various 150w+/channel Adcom, SAE, Sunfire, Threshold and I know I'm forgetting something, amps. About the only ones of those things that just would not get-it-done with the AR-9 were the late-model Yamaha and Pioneer receivers.

They are currently (no pun intended) on an N.A.D. C372 and that combination is "fine" (even "plenty") although maybe not quite as "effortless" sounding as the "big iron" amplifiers.

I'd be a liar if I were to try to identify what it is about the "big" amps that's important. I used to think it was just the ability to provide current. I don't know if it is the type or number of output devices, the size of the power supplies, or a combination. I can't say whether it is damping or the ability to provide current or if it is just the "overhead" power or some other magical effect, but the amps that are so heavy that you hate the thought of lifting them have given me my favorite results.

Why would a Pioneer 125w/channel receiver (used only as an amp, the preamp section being by-passed) give a very different impression than a Threshold 150w/channel power amp? It can't be the 25w/channel difference in the amplifiers' ratings.

After years of goofing-around and having various people accuse me of being idiotic in my sometimes "thinking" one thing or another I've arrived at that place where I understand their arguments. Once you get enough juice, enough being defined as "a lot of power," then hair-splitting is pointless.

So, I repeat; When you get the opportunity to purchase an amplifier with silly amounts of over-kill power, you probably want to do that. 40w/channel isn't even close to getting them to sound like they can.

Bret

[Guest retreatwi]

Thanks guys for all your comments. I do have a Yamaha M-2 amp, but my Yamaha C-4 pre amp isn't working. Plus, the M-2 is an 8 ohm amp. For now my little NAD works well.

Would a more powerful amp make the AR9s sound better or just be able to go louder?

[Mexicomike]

More power provides better control for reasons I know nothing about. But you will usually immediately notice "tighter" better-controlled bass. The ability to play louder is essentially non existant since it takes double the power to make a 3db volume change. 3db is considered the minimum volume change it takes to be just noticeable. So a 300WPC amp can only make a just noticeable volume increase over a 150WPC amp. So it would take 600WPC to make an easily noticeable 6db volume increase over that 150WPC amp.

I'll go out on a potential flame war limb and say that IMHO, no Japanese amplifier of the late 60's through at least all of the 70's and maybe further, was the equal of the high power US amps. One must remember that the interest in Japanese amps was the result of the Vietnam war and the large number of service men who spent time in Vietnam and bought stereo equipment inexpensively through the Army and AF exchange systems. They carried Japanese equipment so that's what everybody bought. Sansui receivers and speakers became a standard fixture in homes all over the country as a result and this "veteran-induced market share" was what really started the Japanese equipment "invasion" of the US. The stuff sucked but 90% of the people that bought it didn't care because it looked impressive. Plus, a Sansui receiver in a PX in Vietnam cost a fraction of a Phase Linear power amp and an associated preamp.

[Diamonds&Rust]

Would a more powerful amp make the AR9s sound better or just be able to go louder?

I'm not trying to be sarcastic or terribly clever when I say, "It depends."

The Pioneer receiver of the early 80s at 125w/channel into 8 Ohms, something more into 4 Ohms, would make the 9s play at earsplitting levels. There was no need for more "power" from that standpoint. I suspect, strongly, that if I were listening to Eric Clapton's "Unplugged" at background noise levels (where I could comfortably speak over it) the Pioneer would have been as good as anything else.

And a "Close and Play" record player would make noise that sounded enough like a guitar and Eric Clapton that at those levels you could tell who and what was being played. I'm not being funny or mean-spirited; it's just that where YOU draw the line of "adequate" is up to you. Thus, "It depends."

If I'm listening to Bizet's "Carmen Suite" at levels anywhere near adequate (not painful), I'm going to notice the improvement with a mighty, mighty amplifier.

Since I didn't do scientific tests I'm afraid to say (or guess) what it is about these big amps that "changes things."

I don't even know if this is true, but there is some urban legend that Dr. Bose found it took a kilowatt to accurately reproduce the sound of a pin dropping. In AR's own live vs recorded demonstrations (I'm thinking the drum comparison) huge amplifiers were used.

I suspect the scientific argument is the dreaded "operating outside the parameters of linear performance" explanation, which might be scientific as all hell but hardly makes a difference when you and I are trying to decide which box, A or B, to purchase.

I'm not prepared to get into one of "those" discussions.

I've owned my AR9s since late '78 or early '79 (I don't recall) and I've gone through times of feast and famine with available amplification; I'm just reporting my experiences. Your mileage is very very likely to be very close to mine.

[Diamonds&Rust]

More power provides better control for reasons I know nothing about.

I'll go out on a potential flame war limb and say that IMHO, no Japanese amplifier of the late 60's through at least all of the 70's and maybe further, was the equal of the high power US amps.

I couldn't not come-back and make an addendum to my "monster amp" post.

You know, I'm not sure that "a monster" is necessary anymore. There are new amplifier designs which are "load invariant" and can operate safely, apparently, with a constant 2 Ohm load.

The fella we're talking to in this thread made it sound like maybe money was an object, so I assumed we'd be talking about a "vintage" amplifier of some sort.

But you know, my Sunfire (that seems pretty "gutsy") isn't that large or that heavy. I wonder about the Wyred 4 Sound and PS Audio amps. My Sunfire was about $1,200 (street) or so when I bought it new, but I'll bet they can be picked-up much cheaper in the used market now.

And if it weren't for the stupid fans in all the big pro amps, I'd be tempted to at least try one of the newer high-output Crowns.

I'm not sayin' that a row of 24 output devices on a heat sink the size and weight of a melted-down dreadnaught has stopped impressing me. But all that metal really might not be necessary anymore.

Can you imagine the distortion that *must* be caused by a small failure to match all of those output devices?

But then again... who cares? As I'm worrying about "switching distortion" and amplifier bias adjustments, and while some still argue the merits of vinyl L.P.s over CDs, the Virgin Megastores are being closed because the world is going to downloadable MP3s.

And here I am still lamenting that I never got one of the solid state Dynaco amplifiers with the neat-o VU meters on the front.

Bret