measuring wow and flutter for tapedecks
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- เผยแพร่เมื่อ 2 พ.ย. 2024
- In this video I am measuring the wow and flutter for two of my tapedecks using the B+K Precision wow and flutter meter 1035.
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In the past I have measured all my decks (10) with a software program. You can read all about that in my blog here:
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I think that you will find that if you open up your tape machine and clean out all the old grease and oil and replace it with new grease and oil, the wow and flutter with be reduced. Over time the original grease and oil collects dust and dirt which makes the wow and flutter worse! They might have dried up also which is a problem that affects wow and flutter... Hope this helps.
It's not quite a knock-off, and not the Kenwood FL-180A. This B&K 1035 is actually a relabeled Kenwood FL-180. I can't find any evidence that B&K ever marketed an "A" version similar to the FL-180A.
The major difference is that the FL-180A has an additional gate time switch in the extreme upper right corner which permits changing between two frequency counter ranges, as opposed to the single range of the FL-180/1035. With the switch set to a gate time of 1 second, the FL-180A's frequency range is 0.010kHz to 9.999kHz (which is the range of the FL-180/1035), and at 0.1 second the range is 0.010kHz to 55.00kHz, unique to the FL-180A. Otherwise, their specifications are identical. There may be some internal/external differences, the most obvious being that the FL-180/1035 have a metal front bezel whereas the FL-180A is plastic, due to cost-cutting measures as the FL-180A is a newer/later model.
As far as the B&K 1035 being a relabeled Kenwood FL-180, the 1035's user manual (still available at B&K's website) actually contains multiple pictures of the Kenwood unit with the Kenwood logo/model# scribbled out, and hand-written modifications and notes to "insert photo of B&K version with the same callouts". It appears to be an initial "draft" of the B&K manual based on the Kenwood manual. IMHO, it couldn't be more obvious as to which company actually built the units.
Also, simultaneously recording and playing back the recorded signal will only provide a W&F value for whatever speed (accurate or not) the signal is being recorded/played at, and it is likely close to double the actual value, since W&F is present at both the record and playback heads, and obviously not the same value at the same head at the same time! Your best bet is to record your own test tape on each deck using the oscillator's output (@ 3000/3150Hz), and then playing back the respective tape on each deck while measuring W&F, and then divide the resulting value by 2 to account for W&F during recording, and W&F during playback. Thus you will arrive at a W&F value for playback.
However, doing so does not guarantee the measured W&F figure as "accurate" without first validating the speed of the deck as "accurate". That is why we have manufacturer-calibrated test tapes (assumed to have been created so accurately as to have no measurable W&F). One must first playback such a calibrated test tape on the deck to be tested, using the meter's frequency counter to validate/adjust the deck's speed to match the test tape's recorded frequency (3000Hz or 3150Hz), and then measure the W&F. Only once the deck's speed has been validated as accurate can any measured W&F be relied on as accurate.
Third-party test tapes are out there, reproduced from a calibrated factory tape, but they won't be nearly as accurate as the original calibrated factory tape. These third-party tapes should at least have the W&F value of the deck on which they were created written on the label, so that this value may be deducted from any measured W&F value from a tested deck... and the deck on which these 3rd-party test tapes were created should be a very accurate deck with exceptionally low W&F, preferably a well-maintained quartz-controlled direct drive deck (e.g. for cassettes, a Nakamichi Dragon with factory specified weighted W&F of less than 0.019% RMS / 0.04% Peak). Even then, can anyone be absolutely certain of these 3rd party test tapes' origin and accuracy?
Nice, but the W&F measurement must be done by recording, rewinding and play-back again. In the monitor mode you will have a different (better) values. DIN measures weighted peak values, the other standards weighted rms (Effektivwert).
And in this case you get twice as high W&F figure, as it adds the recording+playback W&F.
This is a Kenwood the same as mine.
Thank you very much for the video, with a B77, same transport as PR99, i get around 0,06 using software tool to mesure. Not sure if this is in the spec really but i had no issues with "audible" W&F , only when capstan was glazed and pinch roller glazed. But i fixed all those.
From my understanding, testing the "rec and play" method will give me double of normal W&F, so this would mean that my PB / REC taken individually , would be around 0,03.
I think you are right in that assumption :)
sadly, i tested now my GX77, it has a huge amount of flutter at the end of the tape, around 0,13 weighted, start of the tape is just like yours, 0,04-05...
A question, if a cassette deck has less wow and flutter, does that mean the tape is more silent or not? Or it has to do with a noise reduction filter? I want to FIND OUT because I noticed some tapes that I recorded with Dolby HX PRO such as TDK AD and SA-X has excessively much hum and hiss. I was wondering is wow and flutter causing this issue.
wow and flutter are never a factor in tape hiss.
and, btw, Dolby HX Pro is NOT a noise reduction system as Dolby A/B/C/S/SR
Then what it is? All I know that it's a terrible filter that makes old TDK SA-X sound too hissy.
with Dolby HX Pro you can record much higher levels in the high frequency range before saturation. So, if the system works correctly and you use suitable tape, the quality of a record with HX Pro is significant higher on cassette deck. What you describe sounds like a malfunction for me
btw, for technical details look at the article at Wikipedia - its rather good
What is exactly the difference between the weighed measurement and the unweighed measurement?
Hi Guido, please see here: en.wikipedia.org/wiki/Wow_and_flutter_measurement
Nice vid mate. Thanks.
Hello and I have a question about the measurements are you using a calibration test tape? Or are you recording a test tone and then measuring the wow and flutter?
I am recording and measuring at the same time. Have you read the blog?
Can anyone even see the tape on the first machine as its running...???? I cant...
The tape is 35ųm thick, so impossible to see from the side on camera
Cheers
This is a knock off of a Kenwood FL-180A
Without a calibrated test tape, the video doesn't mean a whole lot.