Autocom fidelity

[stpndeep]

[SIZE=12pt]Autocom Super Pro Avi fidelity[/SIZE]

[SIZE=12pt]I've owned an Autocom Super Pro Avi for about a year. Did the research here on the forum to help make my choice (this forum is an unbelievable resource). Installation went flawless and I connected up the iPod to enjoy some of my favorite music. Something just wasn't right, I tried different tracks… sounded the same, the fidelity was pretty poor. I'm probably a bit more fussy about the quality of my audio being a former recording engineer but they claim a 25 to 20 K response and state they are audiophiles, this was a major factor in my purchase. After listening to the Autocom supplied earphones I began the experiments. First high quality headphones AKG K701 and Sennhieser HD 600. this indicated there was a serious roll off in the low frequencies. I then connected my Ultimate Ears 10 pro in-earphones to isolate the ambient noise. This confirmed it, especially when A/B comparing the Autocom output with the straight iPod output. The difference was obvious even to my six year old.[/SIZE]

[SIZE=12pt]So far experiment evidence was my opinion so measurement was in order for proof and communication to the Autocom technicians.[/SIZE]

[SIZE=12pt]I just happen to have a spectrum analyzer lying around, so why not inject some pink noise and see what comes out. This is in no way a measure of over all fidelity but the frequency response is the foundation for which fidelity is built on.[/SIZE]

[SIZE=12pt]The analyzers signal generator is connected into the input of the Autocom ant the output is connected to the analyzer. Note there are no headphone or speakers in these tests it is purely the Autocoms electronic response to a known input signal. The picture below will help explain the results. [/SIZE]

[SIZE=12pt]Results poor, very poor. As you can see, the resolution is set at 4db per step and the results don't look pretty. Beginning about 250hz we begin our roll off (actually when resolution is increased to 1db per step (not shown) it really begins at about 500) and in one octave (125hz) we are already 8db down. When I increase the zero, I can see a slope from 160 Hz at 16db per which means the 25hz spec Autocom uses is really in the mid -40's. I never did see a response at 25hz regardless of amplitude or resolution. WOW! Nearly 4 octaves affected or missing, it responded identical with other injected signals so something gotta be wrong. If all production models behave like this I cant imagine other owners not noticing. Oh yeah, that +4 at 16k is real irritating too.[/SIZE]

[SIZE=12pt]Autocom was supplied the results and has been no help. First they accused me of setup errors then entertained me with a technician that was "looking into it". I'm not expecting much since the tech I was working with to needed to be coached on the methods of using his test equipment, and they have stopped replying to my emails.[/SIZE]

[SIZE=12pt]Am I eccentric… Probably. Nevertheless, these are the facts. I just felt that the forum readers should be aware of exactly what they are spending their hard-earned money on.[/SIZE]

[SIZE=12pt]If your are considering an AVI pro and fidelity doesn't concern you, I have no other issues with AVI pro it appears to do all the other things they claim.[/SIZE]

Anyone else notice this problem with their Autocoms?

 

[LAroo]

I also have been disappointed with my Autocom Super Pro Avi purchase. The clarity of sound from the the Autocom supplied speakers has always been poor. I have never been able to hear my riding partner very clearly. I phoned Autocom but found them very unhelpful.

I have been meaning to acquire the very expensive additional Autocom cable so I can try some in ear headphones.

I have always figured I was the in the minority, as everyone was very positive about their Autocom experience.

LAroo

 

[bramfrank]

I'm also an ex recording engineer. I run a Pro-M1 and that thing has no high end. The speakers they supply are 'peaky' with an obvious resonance between 5 KHz and 8 KHz and rapid drop-off above about 10K. Two headsets, both sound the same.

So I plugged in my UM-2s from Westone and the peak is gone (meaning it is acoustic in nature - no problem, because I was planning to use in-ear headphones for the noise isolation), but the high end is still nowhere to be found.

I also contacted Autocom (and before that Topgear, who until this year were their US distributor) and never got any satisfaction. I asked for diagrams too since I'm an electrical engineer by training and figured I could probably tweak the design to extend the high end (or simply troubleshoot my unit if indeed it was defective - a bad coupling cap or such). They refused.

So these days I plug the UM2s into the Zumo and use it's built-in MP3 player. Certainly adequate for road use, but no one will confuse what comes out of that with anything resembling 'high fidelity'.

It's unfortunate, but if I was riding with passengers, I'd still be using it - as an audio controller it sucks.

Not sure whether I'll go to Baehr or cobble something up myself next.

 

[JamesK]

Wow, you guys really pay a lot of attention to this stuff (especially while riding) - in my case I just need some background music so I don't start hearing voices in my head :dribble: Very nice write up and tests.

It would be really cool to see how the other leading competitor (Starcom) measures up. Or did you both get the Autocom because the Startcom is not even in the same league to begin with?

 

[bramfrank]

James;

Starcom didn't exist when I bought my unit and Autocom was (and continues to be) touted as one of the top two . . . Autocom and Baehr are purported to be 'the best'. I suspect that Baehr is higher tier, if only based on price.

That Starcom is compared to Autocom is solely based on availability - Starcom is to Autocom as Autocom is to Baehr, price-wise. Great marketing, though.

 

[fhaze]

I use Westone CR-1 for my IEM's and I use them with an iPod and an Autocom Pro 7 (the older model). When doing back to back from the iPod direct and through the AC the iPod seems a little fuller, but not by much. Certainly not the amount that appears to be as obvious in your tests. I wonder if they changed something with the Super Pro AVI?

 

[Texan]

I just added a Starcom Advance. Yes, the frequency response is poor compared to almost any other listening device. But I can handle that okay as my ears no longer have flat response (I could use another 6db above 1.5KHz) :blushing: .

However, I doubt that the Starcom is as bad as your Autocom as I think I would recognize so much of the spectrum being absent.

The thing about the Starcom that pains my ears :axesmiley: is the COMPLETELY DREADFUL CLIPPING above 75% volume. At high speeds, the unit automatically increases volume to compensate for increased noise inside the helmet. And then the clipping starts. I've always been sensitive to clipping, and this thing sounds like a square wave at high volume. I don't know what amplifier they are using, but I am quite sure they are not using the whole 12V that is available.

 

[MartyA]

... the COMPLETELY DREADFUL CLIPPING above 75% volume. At high speeds, the unit automatically increases volume to compensate for increased noise inside the helmet. And then the clipping starts.

If you guys can do these tests and report the results that show the shortcomings why can't the people who design and build these things do the same? And then make them right?

Next question - what is "clipping"? I have a Starcom Advance and have been happy with the MP3 and intercom. At low speeds everything is crystal clear. At speed my wife's voice volume increases but buzzes somewhat, like someone with a loud speaker and you can't understand some of the words. The music from the MP3 is very good at any speed, but its volume doesn't increase very much at speed. As Texan says the unit is supposed to increase volume as speed increases, and while it cannot really tell what speed I am traveling it is supposed to sense background noise and filter(?) reduce(?) increase(?) it? Is this where it starts buzzing? Is that "clipping"?

Hope I am not hijacking....

 

[Thug]

Great info guys finally some real world testing on these units...I am fussy also about my music and its quality and not overly obsessive...I like it to sound as it should that's not too much to ask for is it?

Now if some bastard can make a unit for a motorcycle with a waterproof head unit you can use with gloves with a program selector, and volume control they would make a motsa!

Clipping - When an amplifier is pushed to create a signal with more power than its power supply can produce, it will amplify the signal only up to its maximum capacity, at which point the signal will be amplified no further. As the signal simply "cuts" or "clips" at the maximum capacity of the amplifier, the signal is said to be "clipping". The extra signal which is beyond the capability of the amplifier is simply cut off, resulting in a sine wave becoming a distorted square wave type waveform.

 

[RadioHowie]

Hey, wear headphones for a career spanning 42 years and you can't tell the diff between a cow fart and grand opera.

 

[stpndeep]

Never used the Westone's although one of the musicians I work with uses a pair on stage, he seems to like them. The response you see on the analyzer has absolutely nothing to do with the earphones. What you see is pure Autocom electronics responding to an signal injected with equal energy from 20hz to 20Khz. The response out (the graph on the analyzer) should be ruler flat from end to end. Changing to a higher quality earphone be it in ear or over the ear would defiantly improve the sound but there is no earphone that can correct such a horrible frequency response. There is no excuse for a design that cant deliver even this basic requirement.

There are many more fidelity issues other than frequency with the Autocom but they are rather esoteric and subjective so I stuck to what I could measure.

I haven’t tried the Starcom but I’ve been thinking of buying one and give it a shot. Cant be any worse... Can it.

Clipping is a term used to describe when an amplifier runs out of power and cannot supply the peaks needed to reproduce the input signal so it clips them off. This can happen to any amplifier if its driven to hard, some sound better that others when clipping occurs but usually (sometimes its used as an effect like a distorted rock guitar but this is on purpose and shaped) none of it is good.

 

[Scarman]

Good info guys. That makes me reconsider purchasing the Super Pro AVI. I hate to spend that much on cheap electronics.

 

[kleake]

I know this is an older thread, but how does sound quality on the super pro automatic compare to the older units? I just bought the super pro automatic and so far it definitely has the highs, but the low end is not there at all.. I can live with it as overall it's really good, but figured that could be the speakers used. I was tempted to try some good headphone speakers to make it better but haven't got that far into it.

 

[Fairlaner]

I also have been disappointed with my Autocom Super Pro Avi purchase. The clarity of sound from the the Autocom supplied speakers has always been poor. I have never been able to hear my riding partner very clearly. I phoned Autocom but found them very unhelpful.I have been meaning to acquire the very expensive additional Autocom cable so I can try some in ear headphones.

I have always figured I was the in the minority, as everyone was very positive about their Autocom experience.

LAroo

I have 4 or 5 of the cables you need if you wan t to try one....

R

opps didn't notice this was this old....

R

 

[stpndeep]

I tested the unit with the outrageously priced cable too. Results were the same... Lousy

Save your money. The cable or any high priced earphone is not going to fix what is wrong with the Autocom. The signal is just not there, it may be possible to EQ it, but that's usually a poor solution at its best.

This is a design problem.

 

[Fred W]

Although this is a very old thread, the status is (unfortunately) still pretty much the same. The sound quality on ALL OF THESE intercom / sound controllers is fairly dismal. That said, I am relatively happy with the Starcom1 from a total functionality standpoint, but certainly not from a sound quality one.

The key to the Starcom is to never, ever increase the master volume control on the unit above 1/2 way. Seems silly that the engineers didn't just limit the volume to that which is usable, but it is what it is. Instead, leave the master volume low and crank up all of your input devices to drive the Starcom harder. I know, this seems counter intuitive to anyone with an understanding of how audio amplifiers work, but (on recomendations of Starcom) this has been the way to run my units most effectively.

If you do (inadvertently?) advance the master volume above half way, two bad things happen. One, the AGC (Automatic Gain Control) circuit becomes saturated and so there is no longer any difference between volume levels at varying ambient noise levels. And two: the audio amps become over-driven causing severe distortion (due to clipping) especially of the intercom audio.

For the amount of money that these things go for (~$500 a copy when all is said and done) you would think that someone would make a decent alternative to what is out there. But apparently there are not enough of us to create the volume of market that would allow the proper return on investment. And so we are stuck with what we've got.

 

[MartyA]

I'm glad this post was resurrected.

Fred, I wish you had posted a week ago! I've had some issues as I described in my post above, I think now it is "clipping" and maybe contributing to my problem was my adjusting the volume up a bit. If I need more volume and turning the volume up causes me to not hear anyway I wonder what to do then?

But, not understanding gain and clipping and frequency response and all that sound engineering stuff I sent my Starcom1 to the factory last week to see if they can determine what the problem might be. Your post, which I understand a little, might have helped explain my problem to the Starcom engineer better than I did when I asked them to try to fix it. Well, we'll see how it goes.

Snow is melting, I hope they get it back to me soon!

 

[Fred W]

Marty,

The guys I've dealt with at Starcom are OK (sort of). If you don't get any help from them gimme a call and I will gladly see if I can help you. A lot of the adjustments work counter intuitively on the Starcom. Must be some of that advanced Lucas electrics engineering? :blink:

PS - sorry to the OP for the hiJack.

 

[stpndeep]

Although this is a very old thread, the status is (unfortunately) still pretty much the same. The sound quality on ALL OF THESE intercom / sound controllers is fairly dismal. That said, I am relatively happy with the Starcom1 from a total functionality standpoint, but certainly not from a sound quality one.
The key to the Starcom is to never, ever increase the master volume control on the unit above 1/2 way. Seems silly that the engineers didn't just limit the volume to that which is usable, but it is what it is. Instead, leave the master volume low and crank up all of your input devices to drive the Starcom harder. I know, this seems counter intuitive to anyone with an understanding of how audio amplifiers work, but (on recomendations of Starcom) this has been the way to run my units most effectively.

If you do (inadvertently?) advance the master volume above half way, two bad things happen. One, the AGC (Automatic Gain Control) circuit becomes saturated and so there is no longer any difference between volume levels at varying ambient noise levels. And two: the audio amps become over-driven causing severe distortion (due to clipping) especially of the intercom audio.

For the amount of money that these things go for (~$500 a copy when all is said and done) you would think that someone would make a decent alternative to what is out there. But apparently there are not enough of us to create the volume of market that would allow the proper return on investment. And so we are stuck with what we've got.

Sorry to hear about the Starcom. I was hoping that there was a solution out there, and was considering the Starcom as an option. Since my options seem to be limited I'm going to begin the design for a low frequency shelving EQ that would mirror the response of the Autocom. The jury is obviously out on weather the Autocom’s amplifier is capable of delivering this processed signal, but a few simple tests should reveal if this is a reasonable option.

The mere fact that that I'm considering this as a patch is sad. For years as an Audio Engineer I have dealt with individuals making poor choices with regard to "tonal enhancements". But I with limited options one must be creative.

I’m having a difficult time with the designers of the product decision to limit the low frequency response. Its very simple to design an amplifier to have a fairly flat response over the audio spectrum. They must have known, or am I just overlooking something, maybe it was on design decision to control some other factor such as road noise. But that should only be a problem when the microphone is active and that could be compensated at its input just like their literature states.

I’m of course putting too much thought and energy into an issue that very few people care about. I just want the manufacturer to be truthful in their claims for the performance of their product as their brochure states “We are audiophiles and we want our music. Anything other than crystal clear sound is not an option.” And if you read carefully they say “High- Fidelity Speakers” I don’t have issue with the speakers I have issue with what they send to the speakers. If they don’t send it, you don’t get it, regardless of the speaker quality.

Would you buy a car advertised to get 30mpg and be happy only getting 20?... I doubt it. Well that’s what Autocom is selling.

I will post the results as I move forward with this little project.