Spec question

  • Thread starter Thread starter famous beagle
  • Start date Start date
famous beagle

famous beagle

Well-known member
So, in my Tascam 246 manual, it shows two different lines for the frequency response under high speed for the recorder section. What gives here?

Is the first for record and the second for playback ("reproduce")? If so, what's the point of that? In other words, why list record specs if the unit can't play them back? Or am I missing something here?

I notice that in the 244 manual, it only gives one line here.
 

Attachments

  • Tascam 246 Owner's Manual 45.webp
    Tascam 246 Owner's Manual 45.webp
    355.4 KB · Views: 64
miroslav said:
That's the way I would read it.....
Click to expand...

But, like I said ... what's the point then?

And .... how could you even verify that? If it can only playback to 14k, how do you know it can record to 18k?

That just doesn't make any sense to me ...
 
The first line is an overall response range that we can assume contained peaks and dips greater than +\-3dB. The second line shows the response flat within a +\-3dB swing.
 
sweetbeats said:
The first line is an overall response range that we can assume contained peaks and dips greater than +\-3dB. The second line shows the response flat within a +\-3dB swing.
Click to expand...

Ohhhhhhhh, ok. Had no idea. Thanks for schooling me! (and Miroslav)
 
sweetbeats said:
The first line is an overall response range that we can assume contained peaks and dips greater than +\-3dB. The second line shows the response flat within a +\-3dB swing.
Click to expand...


Yep. ^^^^ This is the answer. And on a side note you'll find the Tascam Portas from this era were rated conservatively. Independent tests by Musician Magazine back when the 246 came out showed a solid 37Hz to 15.5kHz +/- 3dB.
 
Cool, good to know! My 246 is in the shop getting calibrated right now. Can't wait to get started on it.
 
famous beagle said:
If it can only playback to 14k, how do you know it can record to 18k?
Click to expand...

I can see sweetbeats' point....but what you're asking ^^^ about is not all that unusual, IMO.

IOW....the deck will accept(Record) signals between 20 Hz and 18k Hz....but can only play them back in the range of 40 to 14kHz +/- 3dB.

It's not a question of you verifying that it can record 20 to18k....it's a question of you knowing that is the deck's working range at input/record.
Also, it would make sense that on playback that range is going to roll off at both ends....hence the 40 -14k.

That's just how I'm reading it....or how it might also be read. :)
 
There are: "Lies, damned lies and Specifications"!!!

Actually that is a very well written and honest specification! You would be lucky to find nearly as good for most modern kit!

Yes, the wider response is the overall one and in fact the recorder might well be within 3dB* over much of that band. Teac only "guarantee" however that the FR will be at least within the narrower limits.

Then, tape response is level sensitive. The low speed specc' will almost certainly be done at neg 20 VU and the high speed one the same or not much more. A good pro or sem-pro open reel at 15ips will beat those HF figures by nearly an octave at neg 10! (tho' in practice there might be an HF stop at 18kHz, especially for a S-pro machine).

VERY badly written speccs' often just sate, for a speaker say, "Response to 35kHz". Well what response? Bursts into flames?

*Just confirms how rubbish tape recorders were! Ooo-err!

Dave.
 
miroslav said:
...the deck will accept(Record) signals between 20 Hz and 18k Hz....but can only play them back in the range of 40 to 14kHz +/- 3dB.

It's not a question of you verifying that it can record 20 to18k....it's a question of you knowing that is the deck's working range at input/record.
Also, it would make sense that on playback that range is going to roll off at both ends....hence the 40 -14k.

That's just how I'm reading it....or how it might also be read. :)
Click to expand...

No. The machine records and reproduces gauranteed within +/-3dB from 40Hz~14kHz, and *something* above/below that range from 20Hz~18kHz. The ranges aren't dependent on the functional state of the machine (i.e. record OR reproduce...the spec is related to record AND reproduce). And in reality the response might even be BETTER than 20Hz~18kHz, its just the levels outside that frequency range are not worth mentioning in the specs...because those would be "VERY badly written specs" as ecc83 put it. The spec must have some reference to it which is why Teac put the +/-3dB range on the 40Hz~14kHz spec. NOW we know what we are talking about.
 
Miroslav .... just say it. Come on ... just try it:


"I didn't know that"

:)
 
I already said in my previous post that I get sweetbeats' point....that means, it makes sense. :)

It wasn't a challange to what he said, I was just saying how else it might be read, right or wrong....and even as sweetbeats said, there is a level of assumption about what is happening within the 20-18k range.

I'm curious now how the specs on my Fostex G16 and Otari MX-80 are written. Honestly....I may have scanned through them maybe one time, so I don't know if they are more or less accruately written.
 
Yeah...point is those two line items on the spec sheet say "this is the published frequency response of the model 246 record/reproduce process."
 
I guess then if we assume the deck is "flat" between 40 and 14k +/- 3dB...then we can assume it's only less flat than that in the ranges between 20-40Hz and between 14-18k Hz.....right?

Personally....I much prefer a graphic frequency response curve showing the roll-off in the extreme lower and upper areas and whatever peaks/dips exist in the 40-14k area....rather than just guess where they are from the numbers given in the spec. If you have -3 dB dip, followed closley by a +3dB peak...that's not very "flat"...but when you just read the numbers without the graphic cruve....you don't know that.
 
miroslav said:
I guess then if we assume the deck is "flat" between 40 and 14k +/- 3dB...then we can assume it's only less flat than that in the ranges between 20-40Hz and between 14-18k Hz.....right?

Personally....I much prefer a graphic frequency response curve showing the roll-off in the extreme lower and upper areas and whatever peaks/dips exist in the 40-14k area....rather than just guess where they are from the numbers given in the spec. If you have -3 dB dip, followed closley by a +3dB peak...that's not very "flat"...but when you just read the numbers without the graphic cruve....you don't know that.
Click to expand...

That is a very fair comment when applied to a device such as a loudspeaker or microphone (the latter are infamous for having poorly written, even non-existant speccs' even from reputable peeps).

But the tape recording process is a fairly "linear" one for FR. fI the head is driven from a current source the magnetizing force should be constant with frequency. The resultant playback response is then proportional to "velocity" (not of the tape!) since it is derived from an inductor. So unless there is a big, midband cockup in the head construction or drive/replay electronics all should be pretty "flat". The problems only arise at HF due to losses and self erasure and at LF due to head geometry, what one writer (now sadly gone) called "bass woodles"!

I MUST see if my Miniflux nomagraphs are still in the loft. One of you might care for them?

Dave.
 
Mmmmmm....I guess the term "flat" can have many interpretations. :)


Response Curves of Analog Recorders


Reading that info ^^^^^ which has most of the peaks/dips with 2dB....not sure how "flat" one interprets a deck with +/- 3dB peaks/dips.
That's why I say that without seeing the actual graphics...the numebrs alone can be assumed to mean a lot of things.
 
I refer to that Endino link often.

Some people want their response as flat as possible...

I think many of the machines that have a reputation for good sound aren't exactly "flat".
 
Yeah...when I fist got my MX-80, I went back to Endino's page and was happy to look at the MX-80 cruves and see his comments that overall, the MX-80 was a pretty good sounding machine, even though it has the low end bump at 70Hz and dip between 100 and 400Hz for 15 ips, which is what I run mine at. That dip helps out with build up in the "mud zone". :)
 
If it doesn't specify a dB window it just means it has "some response" in that frequency range. It could be 50dB down at 20Hz 18kHz. Simple frequency range numbers are almost meaningless, which is why they're used for advertising.

Car stereo gear is notorious for this. They'll specify that an amp can put out 500 watts but neglect to mention that it will be at 20% distortion. In reality the amp will produce about 30 watts at 1% distortion (which is still high).
 
You must log in or register to reply here.
Back
Top