What's up with my BRAND NEW speakers??

**Will Albers** · 10-29-2004, 01:44 PM

Originally Posted by tbird2340

Yet another stupid question. If I get a 4 channel amp and run it correctly with one speaker going to each channel... It wouldn't be possible to add a sub to this amp or would it??

Sure, decent amplifiers will allow something called "tri-way" or the like. Basically it allows you to bridge the amplifer (two channels to 1, to create more power) for subwoofer frequencies and run higher frequencies in 2 channel mode.

I love simple systems, and one that i ran for a long time in my CRX was a two-channel amplifier at 75 watts per channel. The amp plugged into a passive crossover (a box that seperates and filters frequencies). The output of the crossover ran to the speakers... basically 2 channels in, 3 channels out. Everything is crossed over properly so that low frequencies go to the subs and high frequencies to the door speakers. The door speakers received 75 watts and the subwoofer received about 150 watts.

The reason a sub needs more power is because of its mass. it is much less efficient then its higher frequency mates and requires more power to equal the same vaolume.

Anyways, its a VERY simple system and usually sounds great. Plus its inexpensive. Orion sold one for a while through their "Wired" line. They were $50 new, I'm sure cheaper on ebay.

**tbird2340** · 10-29-2004, 01:55 PM

So Will...Are you suggesting I add a crossover if I want to add an amp?

And WhiteRabbit. If Will's reply didn't answer your question here is an email I got from Infinity support:

"Hi Tom,

Thanks for your inquiry to us. The information you were told saying the Kappa cones are subject to cone resonances could not be more incorrect.
The wonderful thing about CMMD is that it actually prevents cone distortion from occurring with in the audio bandwidth of the loudspeaker. This occurs when the cone begins to bend and deflect pass it's normal tolerance and cause a 2nd harmonic distortion (ringing affect). However, the symptom I believe you are experiencing is not caused by cone resonance, but more like a lack of voltage and current which is needed in order to allow a loudspeaker to respond to lower impedances or cone masses that require more force in order to move the cone and then stop it in the opposite direction.

Integrated amplifiers in radios are notorious for advertising that they produce high power which should b enough to accommodate higher power handling loudspeakers on the market. But in most cases they fail to tell you that the high power output is a rating at a very high distortion level (above 10%). In this case your radio is sending a clip sine wave signal to the loudspeaker which can then damage the voice coil after a specific amount of time.

I would certainly recommend that you consider adding an external amplifier to your system which would allow you to play your system at an appreciable output level and also sustain the operating life of your Kappa loudspeakers."

**Will Albers** · 10-29-2004, 02:00 PM

Ohh, one last thing...A riddle:

When you run a set of speakers in parallel, or series, the power is NOT split evenly amongst the speakers. Example, 2 8 ohm speakers in parallel, on a 500watt amplifier at 4 ohms mono does not equate to 250 watts per speaker. Both speakers see 500 watts....

Explain to me why...

**Will Albers** · 10-29-2004, 02:04 PM

Originally Posted by tbird2340

So Will...Are you suggesting I add a crossover if I want to add an amp?

ONLY if you are trying to run a subwoofer as well as the normal speakers. Basically use it if you want to run a 5th speaker (sub) off of a 4 channel amp (your Infinities).
Make sure the 4 channel amp you purchase has a highpass crossover built in. Most do.

And Kudos to Infinity on the response. Glad to see they are doing well with their customer relations

**tbird2340** · 10-30-2004, 06:24 PM

Any idea if an Audio Art NA 4070 is good?

**Snootch** · 10-31-2004, 05:41 PM

Audio Art used to make good amps, I didn't know they were still in business. I assume the 4070 is 70 watts per channel, 4 channels?

**tbird2340** · 10-31-2004, 06:54 PM

It's an old amp... He told me it was 4 X 70 but I don't think that's RMS. I think it's 4 X 35 RMS which I dunno if that will be enough

**WhiteRabbit** · 10-31-2004, 09:52 PM

my apologies. you guys will have to give me the benefit of charity to understand what I was saying, I had hoped I had communicated what I was trying to say, even if I had used improper terminology, but apparently I was mistaken.

When I had used the words "standing waves in the cones", I had meant cone flex in its entirety. Of course infinity denies its existance, thats not good for busness at all! especially if it only happens at lower frequencies from their oval speakers!

anyways, the infinity rep can deny it till he is blue in the face, it CAN happen! at lower frequencies, the cone does "give" a little, creating nodes and anti-nodes of more or less excursion depending on its location on the cone itself.

If this is actually a problem you are having, it is very, very apparent, and it will take about 40 seconds to determine if you are having that issue, once you get the door panel off. Just make the stereo produce the noise problem while you have visual access to the speaker. if it looks fine, then its not the problem. thats not to say the problem doesnt exist, its just that that isnt YOUR particular issue! if it is readily apparent, then it could a major contributor to the noise problem!

the reason I suggest an amplifier could be a help to this problem, if in fact its a problem you are having, is because an aftermarket amp will generally have an offboard crossover, thus able to filter out those lower frequencies.

all the other explanations, by infinity rep or otherwise, concerning anything I myself have said is baggage.

So, to summarize, the cone flex issue DOES occur, I cannot guarantee its a universal problem with all infinities. but it CAN happen, no matter what anyone else says. is it what is going on in YOUR car? i dunno. but now it has been brought to your attention, and you can check for yourself, without any difficulty at all, to see whether or not you actually have this problem. and if you do, youve got some good ideas how to solve the issue. and if not, well then, you know that its not your problem, and you can check for other issues.

**Will Albers** · 11-01-2004, 09:19 AM

Originally Posted by tbird2340

Any idea if an Audio Art NA 4070 is good?

They were once a fine amp. I have never heard of this model so I really can't tell ya the full output. I would aim for a 50wattX4 amp, but the difference between 35 and 50 is very, and i mean very, small. Does it have built in cross-overs?

**tbird2340** · 11-01-2004, 10:15 AM

Here is the question I asked him and his response:

Do you know the year this amp was manufactured? You bought it new and just never used it?? Also, is it rated 4 X 70 RMS or was that peak power that you gave me?

Response

I don't know what year the amp was manufactured. I would suspect that it was sometime in the late 90's though given the condition of the box.
Anything earlier and I would suspect the box would have been pretty ratty by now. The amp was still in the plastic bag and did not appear to have ever been used when I received it and then I used 2 of the channels for about a week. I have the original box and the speaker plugs (one has never been used). There is no manual (I didn't get one with the amp) however it is pretty straight forward. The amp is bridgeable and should be 2 ohm stable since all of the other Audio Art amps were. I did some research on Audio Art when I got the amp and although I didn't find info regarding this specific amp, everything I've found speaks very highly of the company and their products. This amp produces very clean power and was comparable to the PPI amp that it was filling in for. I was told that the 70 W per channel was RMS however without having any available documentation that's all I can say. Again while it was in use, it performed admirably and filled in nicely for my PPI pc 275, which is rated at 75 W per channel. I didn't notice any appreciable drop off in power but I also don't tend to blast my music. I look for SQ and this amp definitely didn't disappoint me. One other thing to consider is that all of the old school amps from that period were underrated since the rating were figured at 12 volts (In some of the info I found on Audio Art it stated that they actually used 11.8 volts to rate their amps).
Unfortunately, I don't have any RCA available. I might have some wiring but I doubt I'm going to have any in the lengths you'll need. I have a BMW and it has the battery in the trunk so I don't have those long runs of wiring. I'm sure I can find a section to use for the ground though.
Anyway, please let me know if there's any thing else I can tell you about it. Thanks, Mike