Miller Mod Saws and the Echo CS-500P

[Chris-PA]

I have a feeling there would be to many variables to consider. A muffler mod will change the pitch of the exhaust. Well I guess I am assuming it goes by sound unlike spark wire pulse's.

Unless you use some sort of pitch correction processing (like they use nowadays to make talentless drones seem like they can sing), it is hard to change the frequency of a signal (acoustic or electrical) in natural systems. You can selectively filter the frequencies out or amplify them, but you can't easily change them.

Sound is nothing more than vibrations, which can be measured, exactly what Chris has done. A muffler mod will change tone but not pitch.

Humans are very good at image recognition, so it is not too difficult to look at a plot and see the lowest large spike and the harmonics (integer multiples) above them, and to separate that pattern from the noise blob below. But it's tough to do that in software, especially when you can't anticipate the type of thing you are looking for or the shape of the noise floor. That's what those setup parameters are for - to try to narrow it down.

 

[barneyrb]

That very well may be. I can only judge him by his posts. By the same token, I don't think a fraction of this crap would happen in person.

And there is what I perceive as most of the problem, judge not lest ye be judged. You are in no position to judge anyone

 

[bikemike]

Is a 034 carb next on the roster for that saw?

 

[blsnelling]

Did you sneak in with a different username?

Nope.

 

[Mastermind]

Nope.

Tell the truth......

You miss me don't you?

 

[blsnelling]

Tell the truth......

You miss me don't you?

You know that I wish things could be right with all of us.

 

[Paragon Builder]

derail....anyone remember the 92cc dolly saws on ebay? Scott Papoosha....I just noticed he is a sponsor at the top of the page. Poosh's Saw Shop.

Nate did anyone ever figure out if he really made them 92cc or not?


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[fordf150]

Nate did anyone ever figure out if he really made them 92cc or not?


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He has only ever answered one of us on bore/stroke and his answer was stock stroke and 54mm bore which is the big bore kit so by his numbers they are only 84cc.

I've cornered him on a couple different Facebook groups and he won't answer a single question.... Even in his sale posts he avoids and eventually just quits posting in his own sale post. The last time I caught up with him I asked how he came up with 7.2hp.... What kind of dyno did he put it on to come with that number... Again he just quit posting in his own sale post.

 

[Paragon Builder]

I should really go see him, try out one of his saws, act like I want to buy it..,I see his ads on Craigslist all the time. He's about 45 min from me.


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[Deererainman]

Sorry about your thread Carl.

I find it very unusual that this same thread is in no less than two other sites and the input has been constructive / very informative. I'll follow your thread on one of the other sites.

I appreciate your sharing the build @MillerModSaws . See you over on the other sites.

 

[Idahonative]

Did you sneak in with a different username?

Respect is earned. You can't buy it, but you can trade it away.....

This whole place is built on a total lack of respect. The fact that I can't send a PM here.....that other sites names are censored....etc. All that shows a complete lack of respect for others.

You will reap what you sow.

Enjoy.

90% of the guys on this forum know what Brad's made of. The other 10% are Socialist trolls from "other sites".

 

[Toad22t]

90% of the guys on this forum know what Brad's made of. The other 10% are Socialist trolls from "other sites".

I like trolls! It reminds me of a little story I heard.......

 

[CR888]

A good forum site requires everyone to contribute in a positive way. We can all work on treating each other better. Disagreeing with someone can be done respectfully if we choose to do so.

 

[GCJenks204]

I told myself I wouldn't do it, but apparently I lied. Ok, a video is made using a cell phone (not equipment designed to preserve acoustic bandwidth content) with an unknown but not really high sample rate. Then it is compressed into a size that can be posted online. Then it is played back into a spectrum analyzer and the result actually believed. No. Simply no. You can get numbers that way, but you cannot get data. I don't think Chris was looking at data.

This site needs a "Best Answer" button like that other awesome site does.

 

[Chris-PA]

Ok, a video is made using a cell phone (not equipment designed to preserve acoustic bandwidth content) with an unknown but not really high sample rate.

The frequency range that is relevant here is about 130Hz to 230Hz, corresponding to 8000rpm to 14,000rpm. Audio spectrum is traditionally 20Hz to 20,000Hz. So the bandwidth is about 100Hz, and well within the range of a modern cell phone or video camera.

Further, the sample rate is adequate to record audio in the upper range of human hearing - let's assume the phone is kinda crappy and only records sounds up to maybe 12,000Hz. The Nyquist rate for that (at least 2x the highest frequency) would be 24,000Hz. Therefore at 230Hz we have about 104samples per cycle, which is overkill.

Then it is compressed into a size that can be posted online. Then it is played back into a spectrum analyzer and the result actually believed. No. Simply no.

This is the audio track from a video. The amount of data in the audio is extremely small when compared to the video portion, so the compression effects are primarily in the video portion. Further, audio and video compression algorithms are an entire field of study in signal processing, and they do not function by changing frequencies within the signal. I happen to know people who have spent a lifetime doing that work, including people who were part of developing the MP3 algorithms. Any audio compression algorithm that could not preserve the data from a tiny 100Hz wide band in an audio bandwidth almost 20kHz wide would be completely unusable.

You can get numbers that way, but you cannot get data. I don't think Chris was looking at data.

By saying it's not data, you imply it is noise. If you look at the plot I posted below, you can clearly see the fundamental frequency and its harmonic multiples. The fundamental is well correlated and some 50dB above the noise floor. Each dB increase represents a doubling of the amplitude. This was actually a damn good quality recording.



In summary, your comment is totally and completely without merit.

 

[Chris-PA]

This site needs a "Best Answer" button like that other awesome site does.

In order to be a "Best Answer", wouldn't you want it to have some basis in reality? Or doesn't that matter as long as someone throws out some technical sounding crap?

 

[Chris-PA]

By the way - I took a look at the audio spectrum from the latest video with the opened up carb, and could easily provide feedback that might be useful to the builder.

Screw it.

 

[jmssaws]

By the way - I took a look at the audio spectrum from the latest video with the opened up carb, and could easily provide feedback that might be useful to the builder.

Screw it.

Is that trolling?

 

[Chris-PA]

Is that trolling?

Trolling from you and others is the reason for it.

 

[bikemike]

Im gonna tell my internet friends that ive never met in person you said that and were gonna harass you.

Scared ?