15 ips bass boost

[themaddog]

I've heard about a bass boost or compression that occurs at 15 ips, but does not happen at 30 ips. Is there such a boost at 7.5 ips? Or is there something magical about 15 ips?

Just curious. Thanks,
-MD

[acorec]

Originally Posted by themaddog

I've heard about a bass boost or compression that occurs at 15 ips, but does not happen at 30 ips. Is there such a boost at 7.5 ips? Or is there something magical about 15 ips?

Just curious. Thanks,
-MD

30 ips loses alot of that "magic" compression simply because the tape at that speed cannot capture the bass. The best speed is, of course, 22.5 ips. at that speed you get 1/2 the benefit of 15 ips (the low bass w/ compression) and 1/2 the benefit of 30 ips (noise reduction/high end clarity). However, this was never the standard. I always use 15 ips on my 1/2 inch and 2" machines because it saves $$$ on tape and I really don't hear much difference (except for a loss in the bass) at 30 ips.

PS: at 7.5 ips, you still get the bass compression, but you also get the "hiss" big time.

[themaddog]

Thanks!

-MD

[cjacek]

Originally Posted by acorec

PS: at 7.5 ips, you still get the bass compression, but you also get the "hiss" big time.

I feel that "hiss" and it being a "problem" is very subjective. I use my TEAC 3440 and Quantegy 407 (I prefer it over 456) and although there is a bit of tape hiss, it is there in the background without it being a problem at all. In fact, I think it enhances the character of the analog sound. (And that's only at 7 1/2 ips mind you). Now, what I can't stand is an audio recording with no audible trace of tape hiss! How's that for subjective ?

~Daniel

[acorec]

Originally Posted by cjacek

I feel that "hiss" and it being a "problem" is very subjective. I use my TEAC 3440 and Quantegy 407 (I prefer it over 456) and although there is a bit of tape hiss, it is there in the background without it being a problem at all. In fact, I think it enhances the character of the analog sound. (And that's only at 7 1/2 ips mind you). Now, what I can't stand is an audio recording with no audible trace of tape hiss! How's that for subjective ?

~Daniel

No, hiss is a problem and is not subjective at all. If it were subjective and not a problem, then 2" 30 ips would have not been invented.

a TEAC 3440, being a four track home stereo machine is alot different than a 2" 24 track machine. I am sure that if you ran a 24 track machine at 7 1/2 ips you would definitely think there was a problem with the hiss. At that point, it would not be subjective. It would be rejective.

Have a great chrismas and a happy new year.

[cjacek]

Originally Posted by acorec

No, hiss is a problem and is not subjective at all. If it were subjective and not a problem, then 2" 30 ips would have not been invented.

a TEAC 3440, being a four track home stereo machine is alot different than a 2" 24 track machine. I am sure that if you ran a 24 track machine at 7 1/2 ips you would definitely think there was a problem with the hiss. At that point, it would not be subjective. It would be rejective.

Have a great chrismas and a happy new year.

I'm not saying that one cannot hear tape "hiss". It's there. I know. What I'm saying is that for one person it might be "too much hiss" and for someone else it might be "the hiss is not bad at all". The same amount of "hiss" is there, obviously, but individuals react to it differently. That's what I mean by "subjective". Now, I'm not sure how a 24 track, 2" tape machine sounds going at 7 1/2ips, but isn't that like recording 3 tracks on 1/4" tape ? The tracks on a 2" 24 track machine would AT LEAST be the same width as my 3440 example. The electronics on a 24 track machine would also be top of the line. Therefore, it's hard for me to believe that a 2" 24 track machine, running at 7 1/2 ips, wouldn't have a similar S/N ratio as my 3440 running at the same speed.

Merry Christmas to you too and have a great new year 2005!

~Daniel

[Farview]

The problem your missing is that instead of 3 tracks of hiss, you have 24 tracks of hiss. If the hiss is the same on all the tracks, every track will add another 3db of hiss. That adds up very fast. Not to mention any additional high end you might need to eq into a few of the tracks (adding to the hiss) to make what ever is on those tracks sound right.

[cjacek]

Originally Posted by Farview

The problem your missing is that instead of 3 tracks of hiss, you have 24 tracks of hiss. If the hiss is the same on all the tracks, every track will add another 3db of hiss. That adds up very fast. Not to mention any additional high end you might need to eq a few of the tracks (adding to the hiss) to make what ever is on those tracks sound right.

Ok, my bad. You guys are right. Thanks for explaining.

~Daniel

[freak1c]

i've been wondering about this question also, i was told that it is a myth that 15 i.p.s. boosts bass response,i was told that 30 i.p.s. picks up high frequencys better and the lack of that at 15 i.p.s. makes people think they're
getting a better bass response at 15 i.p.s.

[Farview]

It is a combination of the lack of highs and the way that the low end gets smooshed together at 15 ips that gives you the sound.

[themaddog]

On the subject of hiss, I used a Tascam 488 without the DBX and couldn't really hear any. You can check me on this, one thing we recorded is here: www.maddogcentral.com/glorious488.mp3.

Yet, on my 388, I really have to use the DBX, otherwise the hiss is just unbearable? Any thoughts on this? The 388 has twice the tape width of the 488, and runs at twice the speed. Shouldn't it be an improvement?

Don't get me wrong, the DBX on the 388 is great and I have no problems using it. You can hear a recording of the same song done on my 388 at www.maddogcentral.com/glorious388.mp3 (DBX on). It's a significant improvement, moslty because we could mike a lot more since we weren't limited to recording only four tracks at once.

-MD

[Beck]

There is an slight bass frequency bump in analog up to 15 ips, but we have a bass loss at 30 ips that is a separate issue. If you are coming from a 30 ips perspective you might describe 15 ips as having a "bass boost."

The advantage is with 15 ips in this case because the fix is a simple matter of rolling off the "offending" frequencies if they are even a problem (usually not). The 30 ips on the other hand is trickier because at that speed the tape just can't capture the sound in the first place. Obviously it can be tweaked.

7.5 and 15 ips machines will capture frequencies above the range of human hearing, so that is not an issue. All things being equal 30 ips has the advantage in the tape hiss category, and technically wow & flutter and distortion. However, with modern tape like GP9 (on machines that can use it) 15 ips has more of the advantages of 30 ips, but without the bass loss.

That being said, I prefer the sound I get with standard tape formulations at 15 ips.

[The Ghost of FM]

Originally Posted by Beck

That being said, I prefer the sound I get with standard tape formulations at 15 ips.

I'll second that big time and also add that machines that are factory designed to run at 30 ips do so not only in the speed of the transport set up but in designing heads that are gapped for 30 ips!

The main reason for bass roll off at all at 30 ips compared to 15 ips is because the machine in question was employing heads that were NOT designed for 30 ips in the first place.

My TASCAM MS-16 deck can be modded for 30 ips speed but, the manual doesn't detail it because they knew that the heads they put on the deck were not designed for it so they smartly left it hidden as a feature.

They're are specific decks out there in the professional realm that are factory designed to run at 30 ips from Studer, Otari, Sony, Ampex and a couple of other strictly pro manufacturers and they in all cases, put heads on their decks that are gapped for 30 ips and all of those cases, you simply end up with a clean, quiet, flat recording deck.

Cheers!

[acorec]

Originally Posted by The Ghost of FM

I'll second that big time and also add that machines that are factory designed to run at 30 ips do so not only in the speed of the transport set up but in designing heads that are gapped for 30 ips!

The main reason for bass roll off at all at 30 ips compared to 15 ips is because the machine in question was employing heads that were NOT designed for 30 ips in the first place.

My TASCAM MS-16 deck can be modded for 30 ips speed but, the manual doesn't detail it because they knew that the heads they put on the deck were not designed for it so they smartly left it hidden as a feature.

They're are specific decks out there in the professional realm that are factory designed to run at 30 ips from Studer, Otari, Sony, Ampex and a couple of other strictly pro manufacturers and they in all cases, put heads on their decks that are gapped for 30 ips and all of those cases, you simply end up with a clean, quiet, flat recording deck.

Cheers!

The 30ips speed is a hotley debated item in the pro world. No matter what the deck, you lose the great low end at 30ips. It is not the heads but the speed of the tape that kills it. I do agree that heads that are not designed for 30ips will make the problem far worse, but my MCI JH24 2" recorder definitely likes 15ips over 30ips.

[cdbstudios]

30 ips = what you hear going in is what you hear coming back

15 ips = what you hear going in is close to what you hear coming back

this is a fidelity answer.

I personally don't like the "bass bump" I like to have what went in, coming back, otherwise the low end starts to get muddy.

Zach
ConcreteDogBicycle LLC
1975 Ampex mm1100 16 track 2"

[Beck]

Originally Posted by cdbstudios

30 ips = what you hear going in is what you hear coming back

True except for the low freqs.

[wildflower soul]

Jack Endino shows graphs of different tape machines here:
http://jackendino.com/graphs/index.html

He doesnt really think 30ips is good on almost any machine. almost