Importance of warm up. I hope this helps someone


I was checking a cassette I had made last month back to the original CD source for comparison. All my equipment had been on for 4-5 hours except CD player. I cued both up and the CD player was overly clear (bright) compared to the cassette made from the same source a month earlier. I thought well since this is a cassette I should expect some roll off in the highs after a period of time but not so soon. OK everybody. Im a cassette fan. I grew up with it and I know other mediums maybe are better. OK back to the warmup. I decided to let CD player warm up for 30 mins. I compared again and cassette was a perfect copy of the CD!!!. I can only figure the CD player was not warmed up. Everything else stayed ther same and was constant. I pay more attention to warmup now. I know it was important but I did not see how much until today.
128x128blueranger
Blueranger writes:

"Most big recording studios still use analog tape. If they record in digital, the digital recording can never be improved upon. With analog they can have it digitally recorded as better digital machines come into being."

I'd ask if he is sure of the validity of that statement. Analog tape, even with half-inch at 15 IPS we used to use in the lab, has problems like print through and instablility in storage. We used to rewind our tape backwards, but even so storage was a problem. Digital tape seems much more likely for use in recording studios these days, but I don't know.

db
I have met many people who claim that the system is without warm up necessity. I have not found this ever.
I've not had mega bucks systems, but in the 10-12 brands I have owned, they all took 20 mins to 2 hrs to warm up, *from constant on condition*. So this is not a power up, this is a signal up if you will.
Some gear like Spectral and Mitner have shown 24 hour power up in my experience. The Spectrals will actually get louder in power up.
But I'm glad to see that Warm up is being recognized.
It's a real pain, because if you take it to the enth degree you have to record a warm up copy before you record the final copy so that all circuits get that time.
I don't go that far, but it is where the theory goes isn't it?
Best Regards all.
Thanks for the input everyone. I always heard warmup was important. I thought I could hear a difference but did not have a good example to go by. There was a big difference. From thin or slightly shrill to a more rounded sound with more bottom end. Mike
I think warm up can be important (and if your CD player doesn't have tubes in it, I recommend you just leave it on all the time), but I am skeptical of the results you report. Cassettes copies are never that good, at least in my experience. When you say the cassette was a "perfect copy" of the CD, did you listen to the new cassette in the exactly the same way you listened to the one you made previously when you decided that it was imperfect? Or did you make this determination by flipping the Tape/Monitor switch on your preamp while you were making the second recording? Rapid A/B switching obscures sonic differences.
Speakers will change response as heat builds up in the voice coils --- you get thermal compression after some minutes of play as the coils inside the drivers warm up. As you play louder the compression will get worse...anywhere from 0.5 to 3DB or more in compression can be expected (enough to be plainly audible). On passive speakers it will also affect the way the passive crossover behaves as the filter will drift slightly.

This effect is volume level and speaker design dependent.....it might possibly be the source of your problem. Certainly, speaker thermal compression could cause the sound to go from a bright sound to a duller sound.

If you have ever played a track very loud (at the beginning) and then found yourself increasing the volume a few minutes later then you have probably experienced speaker thermal compression. (Not to be confused with an old Vinyl trick where the mastering engineer deliberately increased the level at the start of the track to help it sell...as loudness is often interpreted as better sounding)

G'luck!