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I need to locate two or three good .wav or mp3 files on the web at known rpms (idle and driving around 1500rpm would be ideal). I asked about this HERE, and why I need this, but it may have gotten lost. TWO QUESTIONS: Q1 - Could anybody point me to where I might find these? Q2 - Would anyone who has what they believe to be a non knocker/cackler be willing to make a couple of recordings at idle and say 1500rpms and post them on the web. Finally, if anybody with a knocker/cackler is going to record their knocker/cackler could they also include a file at a constant rpm where they don't think they are cackling. Larry |
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Larry, Check out my latest post, it has a link to my cackle wav file http://forums.thedieselstop.com/ubbthreads/showflat.php?Cat=&Board=UBB33&Number=715043&page=0&view=collapsed&sb=5&o=7&fpart= See ya, Shane |
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Beantown, Yep, got it - good recording, can you give me any rpm info as it relates to the wave file time line - especially time periods where the rpm was fairly steady for 4 or 5 seconds. Larry |
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Larry, The last 15 seconds or so I was on a slight incline doing 45 mph, 1400rpm range? lightly feathering the throttle. See ya, Shane |
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Well, Since I got no interest to be able to validate what I've been doing, if I've done everything right which I still have a concern abouit, but if you go HERE and look at the albums for Vehicle 1 data sets on 4/23/02 and 4/24/02 you will see what the acoustic signature of my van looks like. I've also done some analysis of idle knockers and cacklers and their signature is very different and appears to have a lot of strong harmonic structure, but since I got those off the internet, I'm not posting any of them until I can get the wav of a non cackler/knocker off the internet to process and compare to mine which was taken in the actual vehicle to ensure that I'm not getting any artifacts. Of special interest are some of the idle printouts where I had some idle knock with a base freq of 5.75Hz and what the structure is when I did not think I had any idle knock. Reason I'm doing this now is I will only have access to the equip I'm using for another week or so and still need a good internet wav of a non PSD knocker/cackler. I have also posted an album labeled Vehicle 1 Data that has the print out of my vehicle with real bad knock and the processed wave of an unknown PSD, the Duramax and the Durmax tick. Larry |
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Larry, Here is my '02 at Idle. I don't think it has knock. It has no mods yet. Listen to it and do an analysis and let me know what it looks like. http://www.geocities.com/jasonspangler/mp3/ |
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dtb, If it's quiet enough I will do it in an hour or so. Using the computer, sometimes there is too much ambient noise. Do you want me to post the readout on my webshots site in a public album and give the specifics or do you want it put into a private album with access limited to you, me and maybe one or two other people. Since I'm not sure just yet if any of this really makes sense, I'm a little cautious to post the results publicaly w/o the vehicles owner's approval. Larry |
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Sure, It's ok with me. The recording was done with a compaq 1500c laptop using standard windows recording software and using internal mic. Computer was sitting on the drivers side battery with hood open. When (if) I get time I wil re-record with an external mic placed inside the cab on the firewall. I will also do one at 1500-1600. David Edited by dtb (05/01/02 03:23 PM) |
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Larry and David: I would be happy to make recordings of my 2001 if either of you can give me a few quick pointers on making recordings with a laptop. My wife's COMPAQ Presario 1800T is available but I have never used it to make recordings with a mic and looking quickly at the "Your Notebook at a Glance" can't seem to find an internal mic. If either of you can give a short lesson I will make some recordings. Thanks, Arch |
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dtb, It's there and I'll jump over and put it in the public arena. When I did your plot I processed approx 10 sec of data, stored it and processed the ambient noise with the windows player off for an equal 10 sec period as a reference to see if any background spikes were there. This ambient was within about 5 sec of processing your data. Finally don't forget the absolute dbs are meaningless, but relative comparisions is probably O.K. Also the vertical lines are harmonic lines of the base freq. which in your case for the highest level was 5.5Hz. The machine only allows for around 10 harmonics so all the stuff to the right you have to guess at. Due to storage limits on the machine I did not keep your info for further analysis. I'm still waiting some expert opinions from signal processing experts and those familiar with this analyzer to double check me and make sure I've not done something silly. I'm quite worried that running this thru my computer microphone and then into the calibrate mic could give some funny results, but I don't think that maybe the case, but not being an analyst expert, I simply can't be sure. Also remember you are not looking in the time domain that humans normal live and hear in, you are looking in the frequency domain from 0-100HZ with most of the harmonic structure under 50HZ which is not very audible to the human ear. And your plots are somewhat interesting at least to me because some of the harmonic spikes are either lower or wider than other knockers I've looked at. ON EDIT: one thing I forgot to mention is that I used the mp3 file that you posted a week or so ago that I have stored on my computer to do this since your website was not available when I tried to so it online. So if that online file is different then this is not representative of it. Larry Edited by Larry M (05/01/02 04:18 PM) |
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Arch, I know nothing about recording using my computer. I think just about anyway would be fine, but it needs to be reasonably loud and not real real soft. Dtb's level played back on my computer was just loud enough, much softer and it would have been harder to process. I really need to see several .wav or .mp3 files on the internet from a non cackler/knocker that when processed like I have all the others shows a plot similiar to the one in my album Vehicle 1 Data at idle that doesn't have all this low freq harmonic data in it along with files at knnown rpms that show either no strong harmonic lines that seem to be cylinder freq related or no strong lines at all like I've been getting on my Van. So far the only one that has come close is the one of the PSD rev that was posted in the PSD Sounds thread HERE, but since I don't know the rpm I'm not sure how to equate it to others - it seemed like that recording was of a good non cackler running at around 1750rpms. Larry |
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Larry, thanks, my wife is gone in my truck this afternoon...had to pick up friends at the airport...she never drives my truck unless she can't get her "stuff" in her car. Anyway maybe David (or someone else) will reply with some pointers or I will figure it out (hopefully). Arch |
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Larry,,I dont THINK my early 99 has Cackle or knock,,there is a wav of my exhaust idle and rev...would not have the knock or cackle..I have a mic ,that will reach under the hood...and I could try to drive it and make a couple wavs....tell me exactly what you would want and I will try to accomidate you! I have a Compaq presario..and would be using windows software. The mic is on quite a long wire..I think it would go just under the hood...for a good motor wav. |
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JimTJr. Anywhere for recording is fine, just document the rpms for each recording and make sure it's like 20 secs at a steady rpm in length and do the idle recording. Larry |
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Will do..ASAP. We have church tonight..so tomorrow after work I will try to get to it. |
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Arch, Got your idle.wav file and it's signature looks exactly like all the other "knockers" I've processed, a strong 5.75Hz base freq with strong harmonics. Do you want me to post it on my webshots site or what? Larry |
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Larry, yes please post it and hopefully I will be able to get you some more wav files this AM. Arch |
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Larry, I sent you a private message. Dennis |
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Larry, it's still AM here but barely...anyway you have e-mail. I sent you three new wav files. Arch |
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Arch, Did you get a new vehicle  . The recordings came out much softer than your first one and it's the middle of day here and the A/C is on so the ambient is up and funny, so I may have to wait till real early tomorrow AM when the background is better behaved. The 5-2 idle wave at first look is nothing like the 5-1 idle wave and what little freq structure there seems to be in the 1500 and 1700 wave files doesn't at first glance look like the freq structure found in cackler's, but need some quiet time to look further and make sure. Just, remember what you hear with you ears is very much different than what the plots show. As compared to my vehicle yours so far comes the closest at higher rpms.
Larry |
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Larry, I had hoped for more noise like I get when I first start it but we have had abnormally high temps for the past few days and it was approximately 75* this AM so as my luck would have it not much noise. A cool front is blowing in as I type this message so maybe I will be able to get my "normal" cool weather noise tomorrow in the AM. Remember the idle recording I sent you yesterday was with the mic under the hood and actually directly above number eight cylinder. It would be very difficult to convince anyone that my truck has a problem the way it ran this morning. |
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Arch, Boy I'm glad to hear that, because that is what my first cut showed from a frequency view. As I said I will be able to get better info tomorrow when it's quieter. I could by looking at the real time data and not the averaged that in the last three recordings, your vehicle seemed to want to cackle especially in the 1700 rpm wave file, but just didn't seem to be able to get there. Plus when I look at real time data it has to be done in real time and can't do much post processing on it. If my processing tomorrow confirms what I believe I saw today along with your comments your data has helped tremendously. Also, I maybe getting together Sat. with another member and can do some work on his vehicle directly like what I've done with mine and see how they compare. On thing that has me worried is that my van has neither an intercooler or wastegate so they are physically different. Larry |
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Is anyone going to post up some non cacklers running at the 1500-1900 rpm range? I want to hear some things... |
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Ok,,Need some HTML help here....I cant seem to figure out how to make a link to a wav..I know how to make a wav file load automaticly when a page loads. How do you make a wav play when someone clicks on a button..or link? Any help>? |
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Larry, I just got a chance to review the graphs on your webshots...did you learn anything? We got a lot of rain here this AM and it didn't stop raining until almost noon. Anyway I have not made any more recordings but after I have a little lunch I will go start the truck and see if the noise levels are greater than yesterday and if so will make more recordings. The temp is now about 65* and 90% humidity. Arch |
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Larry, you have e-mail and I will answer this time before you ask the question...no I didn't use a different truck. What a difference a day makes. Also, the truck did not move since I made the recordings yesterday. Arch |
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Arch, Got the E-mail and will try and process tomorrow A.M. In reply to your previous question on did I learn anything.... In a way yes. 1.It seems more and more unlikely that using wav files off the computer are introducing significant artifacts and will know more tomorrow if I get a change to do some real in vehicle mesaurements on a F-series. 2. If the acoustic pattern for cackle is what appears in your plots B3 and B4 which my vehicle doesn't exhibit what we hear as cackle might be some audible manifestation of this acoustic pattern resonating in the engine. You have to appreciate the relationship between time domain events and what they look like in the frequency domain. To kind of put this in prespective I have added an album entitled Reference Sounds and have included a freq plot of me banging a spoon on a small al. pot. If you look at that plot you see a couple of fairly quick decaying harmonics, but nothing like the strong harmonics in cacklers. In fact I've look at one vehicle where the base freq seems to be almost non existent, but still shows a strong harmonic structure. If it is this harmonic structure that is really causing some problem, then not hear the source of the base frequency (i.e. the spoon hitting the pot) you still could have just as much of a problem as when you hear the base source of the harmonic structure. I hope I gave you a feel - what I trying to get you and others to appreciate is that if we hear or don't hear this tap/bang/cack, the problem that we can't hear is the harmonic structure that this bang is setting up usually in a confined space. Also the harmonics may also be causing overall noise by unknown paths/interactions. Your two idle plots kind of show this when combined with your actual evaluation. You I believe indicated the day of the second idle wave the engine seemed to run very smooth, unlike the first day. If you look at the two idle plots, the first one B1 has these cylinder/injector/firing event base frequency of around 5.75 to 6Hz very strong and with many strong harmonics relative to the overall engine noise level. The second one B2 still has this harmonic structure but the harmonics are not as strong as compared to overall engine noise level and are undefined after about the 7th harmonic. Some other knocker's I've looked at which exhibit similiar for lack of a better word "messy and ill defined" freq plots have less audible knock than those with a pattern such as your B1 plot where the audible knock is very pronounced. I haven't look at you most recent e-mail but if it was loud I would except to again find strong and many harmonics related to some cylinder/injector/firing event. I'm far from a well qualified acoustic analyst, but am trying to get some that are qualified to look at the data that I have collected and help out. Don't know if that will pan out but as they say "hope springs eternal". As I've said before without having a cackler or a lot more exotic equipment which I would be unqualified to use, I see no way to isolate the actual source of these frequencies and if the true fix for cackle is their elimination then from what little data I've processed, I've not seen anything that eliminates or significantly reduces or alters this fundamental acoustic signature yet. With my vehicle when I have the loud idle knock I have this frequency structure, and when I can't hear it most of the time this frequency structure is not present. Thus I assume that knocker's whether audible or not will have some form of this acoustic structur. Mind you I haven't fixed anything, but have just observed what kind of acoustic structure seems to exist for a knocker, non knocker, light cackler, heavy cacker, and non cackler. I can't get mine to cackle and do not have the acoustic structure similiar to your plots B3 and B4 which while you thought the truck was running smoothly has the same basic acoustic structure as the real bad cacklers that I have looked at where you can audibly hear the cackle. Also these strong cacklers seem to have the very strong and mulitple harmonics relative to overall engine level noise. Larry |
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Neat idea, Larry. My computer connection is too slow to load and listen to the recordings... but I sure wouldn't mind reading your summary. Do some folks, who don't believe they have the cackle, have nearly the same sound signature as other folks, who do believe thay have the cackle? {oops, I didn't realize there was a second page before I posted the above... but I don't suppose it matters, cause now I'm completely lost with where you are going with this anyway... I'll check back tomorrow when my head is clearer.} Edited by Robyn (05/03/02 06:10 PM) |
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Robyn, Thanks, I don't know where it's going either and will probably take a much smarter person than me to really make sense out of all this, but I believe that the true sources lies somewhere in this approach and I'm out in "Right Field shagg'n flies" anyway most of the time. This is how heavy machinery, ships, etc. are often diagnosed. It's just I have a lack of good data to analyze with a few exceptions and don't have either the ability, knowledge, expertise to really exploit what this approach has the potential to do. I can think of only one other person who is not a member here appreciates what this can reveal when properly interpretated and correlated with knowlege of this engine and we're not allow to hear his solution  . In fact I haven't seen good data sets posted of all the current solutions to this problem, but would like to see some.
Larry |
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Larry, I think I need to clear up a couple points. First, the idle wave that I initially sent to you was made with the mic under the hood as I mentioned yesterday BUT...I would not say that the truck was running poorly...the reason you could hear the idle knock so well is because of the mic's location (just above #8 cylinder). Second, my truck rarely RUNS POORLY...I can only recall one time when there was a definite MISS. Third, using the computer to make recordings...there are numerous settings available on the WINDOWS recording funtion e.g. quality settings (radio, CD, telephone) and frequency range settings. I used minimal settings to keep the file sizes small. It might be interesting to use higher quality settings and send you just one file e.g. and idle wave and see if you can detect any difference. Let me know if you want to give it a try. Thanks Arch |
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Arch, Based on what I've seen the location and type of equipment seems to make very little difference. Remember this isn't a lab quality project. I have simply processed the information and it's more of the structure and relative levels that are important. I.E. a mic under the hood will have higher spikes, but also higher overall level vs one inside the cab where the spikes and overall levels are both reduced. Also, this is averaged data over about a 12 sec period and what you are seeing is not what you think you are hearing, we humans hear in the time domain (i.e. spatially) this is in essentially another dimension so to speak the frequency domain. Look at the pot banging plot, do you hear anything but the spoon hitting the pot(also this was not a recording where you got ringing of the pot), you hear a sharp tap, but the freq domain sees not only a spike if the taps are repeative, but an increase accross the entire freq spectrum of increased freq levels along with a couple of sharp harmonic spikes that delay rapidly you hear one hit the freq domain sees much more acoustically. Finally, these plots don't necessarily IMHO show whether a truck is running poorly or not, it's about whether they have this acoustic signature of those that cackle. The could well be other variables (such as a scored injector, low fuel rail pressure) that in combination with this freq structure that makes the cackle phenomenon noticeable in terms of mpg, performance, audible noise, etc. Larry |
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Arch, Sorry for not getting back earlier, but was getting trailer ready for the towing season. I processed two of you 5-3 waves, but the ambient for the idle wave was ready flaky this A.M. and couldn't get good plots. Here are two links that caused me to do a lot of this that you might find interesting reading. It's amazing how much past info is lost in the heat of the moment. Since being archieved the first link has only had 6 views and the second 14 views and several of those have been by me .
IDLE KNOCK and What's Happening Do I have Cackle/Knock?... A test to try.... IMHO the second link by someone who based on my research knows a little more than casual knowledge is very enlightening to say the least and directly relates to what I have been attempting to do. Note in this thread the 5.5Hz freq component and how it might or might not be heard. Mine doesn't have the 5.5Hz freq like the knockers and cacklers whether they have the audible symptons or not. Larry |
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Arch, I processed your 5-3 wav files and posted them. I had to include a ambient plot to use with the idle wave since I was getting some background spikes around and above about 45Hz that will corrupt to some degree your idle wave plot. Larry |
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Re: Non knocker/cackler .wavs needed
