Axiom Home Page Forums General Discussion Technical Questions How to wire a vintage AX120 Subwoofer

Hello,

I recently bought a pair of vintage Axiom subwoofers. The name plate sticker on the speaker identifies them as AX120 Sub as seen in the picture below (as long as I loaded the pictures right).

I cannot find anything on the internet to show me how to wire the speakers. I phoned the Axiom support line and he had never heard of the speakers and did not have any data on them either.

I did find one brochure copy on the following Axiom webpage http://www.axiomaudio.com/images/HomeTheater_AX.jpg but it does not show my exact speaker and it talks about an active subwoofer whereas mine are passive. The are 4 sets of input/output posts as shown in the pictures below with no indication on the speaker as to what the function is of any of the posts.

Before I start to test wire them and try to figure this out via trial and error I am asking if anyone has seen these before and can give me some hints as to what to wire where.

I am surprised that Axiom has no data on these speakers even though they are old.

Any help is much appreciated.

You would want to run speaker wire from the amplifier/receiver L and R terminals to the corresponding two L and R terminals on the subwoofer labelled INPUTS.

Then connect separate speaker wire from the left and right terminals labelled OUTPUTS on the subwoofer to the binding posts on your corresponding left and right speakers.

The problem I see is the INPUT AND OUTPUT terminals are not labelled on the subwoofer. If I had to guess the bottom two are the INPUTS and the top two are the OUTPUTS...this is just a guess...it could be the other way around.

PS. Also remember maintaining consistent polarity with all this wiring is critical.

DrBones,

These subs are so old (30 years-plus) I don't remember seeing them, although the model number rings a bell (from audio-video equipment directories I edited in that time for Sound Canada magazine).

BlueJay's advice is solid, but since there are no labels, you should either remove the rear panel of the speaker or the woofer, whichever is easier, and trace the wiring. In most speaker wiring schemes, the black lead (sometimes it's white!) is generally negative and the red lead is positive. Find the two leads that go from the input connections to the terminals on the driver. There may be an internal passive crossover. The input leads would go from the external connections to the crossover, then to the two terminals on the woofer. There may be a second pair of wires from the inside of the input connectors to the second set of connectors. The latter would be used to bypass the crossover and power your main speakers with a full-range (unfiltered) audio signal.

As Blue Jays advised, keep the positive/negative wiring polarity consistent.

At some point Ian may see this post and remember how these things are wired.

Regards,
Alan

i guess they made different versions of the AX120 sub because the one in the picture looks different than the one in this brochure .

edit, i realize that the one in the brochure is called a compact AX120 sub so that might be why they look different!

I also realized that the link you put in is the same link i put in; so, there ya go!

Bones, welcome. There was a previous discussion here relating to the AX 120 terminals. The picture there(apparently of a later version than the ones you have)shows that the output terminals are the top ones. It would seem likely that yours follow the same pattern.

The only specs seem to be the ones in this table.

You don't mention exactly how you're planning to use the two subs, but if you're thinking of setting them up as "stereo" subs(although there's actually little or no stereo bass in recordings), you'd connect just one of the stereo channels to each AX 120. If you then feed the front speakers from the speaker level outputs on the AX 120, apparently there's a 120Hz high-pass filter on those outputs, which'll roll the front speakers off below that frequency.

Hello BlueJays1,

Thank you for your ideas. You are right that the problem is no labelling for the input or output terminals. My confusion goes further when I attempt to figure out why there are so many terminals on the speakers. The speakers are for my 16 year old son (I thought I would start him out on Axioms right away, albeit older ones)and I have planned to use both of the subwoofers along with a pair of AX2 bookshelf speakers utilizing the high pass filter that they apparently have inside.

JohnK`s response helped my thinking in that the four pairs of terminals must be for when you are using one subwoofer and filtering to two bookshelf speakers. Since I want to try one to one I will attempt what JohnK suggested and run one set of wires to one of the input terminals and then to the AX2. However now I have more guessing as to not only which is the input/output but also which of the pairs should I use for the one on one filtering I want to set up!

Although I wanted to avoid opening up the speaker for purely time managment issues I think I will have to do what Alan suggests and get my nose inside the units.

Thanks again.

BTW. It is hard to see in the pictures I posted but the polarity is clearly marked on the speakers. The black is negative and the red is positive so keeping the polarity consistent will be easy.

It doesn't appear that the second "guess" you mention is critical. If for example, you connect the left channel output of the receiver to either the left or right column of terminals and then on to the left AX-2, that AX-120 will play the left channel bass and that AX-2 the left channel higher frequencies.

I always like seeing photos of older axioms (or any other speaker). Designs have changed significantly over the years!

Hello Alan,

I am honoured to have partially stumped you. I read your blog posts all the time and I have learned so much from them that you have reached near deity status around my household. To boot I am also old enough to remember you from your time with Sound Canada magazine!

Your suggestions are solid and I will go ahead and puzzle it out from the inside of the cabinet. I will post another time after setting up and doing some listening tests.

Cheers

James

Hello JohnK,

I agree with you. I was thinking along those lines. The first `guess` should be taken care of by looking inside the cabinet and following the wiring as Alan suggested.

I appreciate your thoughts JohnK and as I mentioned in my reply to Alan I will post an update once I get the connections correct and do some listening comparing the AX-2 by themselves and then with the bypass filter and the AX-120 added.

James

Hello Terzaghi,

I agree with your interest on seeing the vintage designs of speaker companies. The design in this pair of subwoofers makes me wonder why the binding posts are on the front of the speaker with no cover to hide the wiring. I am not sure what the primary reason to do this would be by Axiom.

I understand that the subwoofer can be placed out of sight and work effectively but in our situation this setup will be used in a small apartment/university dorm room and therefore will be stacked for space saving underneath a set of AX-2 speakers that have the same isosceles trapezoid (near a triangular) shape. We won`t be able to turn the speaker around to hide the wiring because of the distinct isosceles trapezoid shape of both speakers. One trapezoid backwards stacked underneath another trapezoid facing forward would look weird and be unstable.

I bought the speakers for my son from different sellers because they were cheap given the vintage and I wanted to hear what old Axioms would sound like. He has been playing the AX-2s in his bedroom (about 10 square meters) and they sound good. By themselves my wife thinks they have more than enough bass but you know us guys. We can never get enough clean bottom end. That is what brought on the experiment with the AX-120s.

I will post an update sometime later on the sound check once they are wired up.

Cheers

James

If you don't want to take the back off there *might* be an easy test...

Hook up the speaker wires from your receiver/amp to the top left/right terminals, play something with some bass, then move the wires to the lower left/right terminals and play the same track again.

My guess is that one of those hookups will give a lot more bass than the other -- the "more bass" hookup is the one you want. The other one should provide less bass because the high pass filter is blocking bass from the subwoofer (rather than blocking bass from your mains as it was designed).

You could probably test with just a single channel and get the same results.

I suspect the binding posts are actually on the *back* of the speaker and the woofer is supposed to face the wall... but when pictures are taken the speaker is turned around because otherwise the pics would be really boring. Is the other side of the speaker finished or is it "the ugly side" ?

Did a quick search on having subwoofer driver face the wall or face the listener... to the extent there was a pattern, it seemed to be "maybe sounds a tiny bit better with driver facing the wall, but then I have all those ugly wires visible" (since most subwoofers have the driver on one face and the wires on the opposite face).

AFAIK at subwoofer frequencies there is no directionality to speak of, and no real concern about the wall absorbing more sound when the woofer is facing it. A couple of people have told me that "the primary reason for having the subwoofer driver face the listener is because some people like to watch it move".

John, on your first suggestion to try it both ways, there might be a problem. If there's a polarised capacitor for the high-pass filter, connecting it backwards can cause it to explode. If the enclosure was opened, the presence of the filter(which would also have a directional indication if polarised)connected to one of the terminals would answer the question.

As to what you suspect about that actually being the back of the sub, I tend to agree(by about a 60/40 margin). Looking at the picture I linked from the earlier thread, the "right" terminals are shown to the left. This would seem to be illogical(requiring the wiring to the mains to cross over each other)unless that was intended to be the back and it would then actually lead toward the right main.

You found left/right markings ? Good catch !

re: polarity, isn't the speaker signal going to be AC, no significant DC component ? My assumption had been that direction wouldn't matter in that case but maybe I missed something...

i think the signal is DC.

Actually, since audio signals are AC waveforms, speakers use AC to reproduce them. DC can only move a speaker driver in one direction from their neutral point -- outward (or inward if wired that way). Note how all the energy in the red dc line lies above the horizontal axis:



If you send a mixed AC and DC signal to a speaker, the DC component will effectively move the speaker's neutral point outward (or inward depending on how the speaker is wired) and increase the likelihood of distortion.

Here is an update on the Axiom AX 120 vintage subwoofer. I finally had the time to look inside the speaker so while referring back to the pictures I posted this is what I found. The lower terminals have wires that go to the upper terminals and what I believe is a crossover filter. The upper terminals have wire that goes to the woofer. I am going to run input wires to the lower terminals from my receiver and then output wires from the subwoofers to my AX2 speakers. I will let you know how it sounds after some listening tests.

If the upper terminals go straight to the woofer, then it's the lower ones that that are actually behind the crossover filter.

If what you're saying is that the wiring is lower terminal to filter to upper terminal and upper terminal to subwoofer driver, then the upper terminal has to be the input.

Hi,

I'm new here and was looking for info on the Axiom AX 120 sub but find I may have something to contribute, too....I was reading the thread about the wiring of the AX120 and the stickers are still on my AX120....so here's the wiring setup (externally, anyway)

It's awkward to photograph it at present so I'll try to describe it...

With the AX120 standing with the speaker itself at the top and the connections below, the labels on the upper connections read Satellite Output (L&R)....

The lower speaker connections are labeled Main Input (L&R)...

N.B.: when facing the connectors the RIGHT side spring clips connect to the LEFT speakers and the LEFTside spring clips connect to he RIGHT speakers

Hope this helps somebody...

Regards,
Taras

Taras, welcome. Yes, the connections as you describe them on your AX120 appear to be the same as the ones on the different AX120 version which I linked above in post #374692. The outputs are the top terminals, and the right terminals are on the left(facing them)since that's the back of the sub.

James(DrBones)didn't check in again, so hopefully his AX120 didn't go up in smoke.

The only AX120 info that seems to be available is the specs in the chart also linked in the above post.