Saturday, June 17, 2017

Calculating File Sizes (How much hard drive space does it take to record a song?)

So . . .  you want to record a song and you're running out of space on the computer's hard drive? Wondering if you have enough room? Here's how to figure out if you do have enough space:

The sample rate and bit depth of the audio you record are directly related to the size of the resulting files. In fact, you can calculate file sizes using these two parameters:

-- Sample Rate x Bit Depth = Bits per second

Or, stated another way:

-- Sample Rate x Bit Depth x 60 = Bits per minute

In the binary world of computers, 8 bits make a byte; 1, 024 bytes make a kilobyte (KB); and 1,024 KB make a megabyte (MB). Therefore, this equation can be restated as follows:

-- (Sample Rate x Bit Depth x 60) / (8 bits per byte x 1,024 bytes per kilobyte x 1, 024 kilobytes per ---  megabyte) = Megabytes (MB) per Minute

Reducing terms gives us the following:

-- Sample Rate x Bit Depth / 139, 810 = MB per Minute

A lot of folks are recording these days at 44.1/ 24. That's a sample rate of 44,100 with a bit depth of 24 bits. Here is the calculation:

-- 44,100 x 24 / 139,810 = 7.57 MB per minute.

Here is a basic chart of different sample rates and bit depths:

44.1/16 bit  =  5.04 MB/minute
44.1/24 bit  =  7.57 MB/minute
48/  16 bit   =  5.49 MB/minute
48/  24 bit   =  8.24 MB/minute
88.2/16 bit  = 10.09 MB/minute
88.2/24 bit  = 15.14 MB/minute
96/  16 bit   = 10.99 MB/minute
96/  24 bit   = 16.48 MB/minute

If you figure a normal song of 3 1/2 minutes recorded at 44.1 sample rate and 24 bit, you can plan on it taking roughly 26.50 MB of disk space. I am starting to run a lot of my sessions now at 96/24 bit. So a 3 1/2 minute song is costing me 57.68 MB of hard drive space per song.

Considering that terabyte hard drives are now running close to $50 these days, all this math stuff is not nearly as important as it was just a few years ago. But I know a lot of guys who still aren't purchasing a whole lot of TB hard drives! It's still useful information if it's needed in a crunch!

Hope this helps!

HEY!! Make it a great day!!


Tuesday, June 6, 2017

Organize Pt. 3 (patchbays)


Having a patchbay helps to optimize your signal routing and organization. Even the most modest of studio setups can benefit from the simple addition of a patchbay. Almost any configuration of cable connection - xlr, 1/4" TRS jack, Cat5, etc. can be connected to a patchbay. And you can make your connections without ever having to leave your seat!

If all your equipment I/O is connected to the patchbay and it is labeled well, it will save you time by not having to go around the back of your gear to connect things. It will save wear and tear on the connections of equipment. It also centralizes the grounding of gear and reduces potential ground loop noise problems.

I use two main types of patchbays in my studio: xlr and 1/4". The [Hosa] xlr patchbay is configurable. That is, the two types of xlr - male and female - can be configured to fit one's needs. You can have the front panel all xlr male, all xlr female, or a mixture. Conversely, you can set the back of the patchbay as well.

The [Neutrik] 1/4" patchbay has a two-row topology and is typically set up with an out-over-in signal flow, or a downward signal flow direction. For instance, outputs on the top row and corresponding inputs below. Or, sends on top and returns on bottom. TRS patch panels have configurable setups called "normalled" and "half-normalled". In patchbays, a normal is an internal connection from the top row of jacks, to the bottom row. Normalling allows connections that are normally in effect to exist without the need for inserting a patch cable in the front of the bay. For example, the stereo outs of a mixer are generally connected to the inputs on a stereo mixdown deck. By connecting the mixer’s outputs to the top back row of a normalled patchbay’s jacks, and the mixdown deck to the bottom back row, a connection is made internally in the bay, and does not require extra patch cables. 

When a jack is inserted into the lower plug, however, the normal connection is broken. This provides a convenient way to route signals to multiple destinations. For example, the output of a mixer that is normalled to the input of a DAT on the patch bay can also be simultaneously routed to another patch point. To do this one would simply run a patch cable from the patch point that is the output of the mixer (an upper jack) to the patch point that is the input to the other device (a lower jack). This connection will break the normal of what would normally be feeding that other device in favor of the mixer signal that has been patched in. Signal will now be routed to the DAT and the other device. Another application might be to insert an EQ after a preamp but before the converters. Simply route the output of the EQ (an upper jack) to the normal input jack (a lower jack) for that mic preamp.

As a final note - label, label, label!! In a previous post I mentioned owning a digital label maker. This is when it comes in handy! Also, write all the routing options down on paper first to help figure out organization.

Having a patchbay will simplify your studio life and make routing an easy task!

Peace - and HEY! make it a great day!!