BEGINNER: Frequency Sweep

[SBMastering]

Like I said in the previous thread, I've been quite busy, and I'm just getting back to working with Synthmaker. Still a beginner here.

I'm working on a calibration tool for my analog gear and subwoofers.

I would like to build two modules:

- Frequency Sweeps -- When this button is pressed, there is a continuously looping frequency sweep from 10Hz to the highest limit at the given sample rate. I would like to be able to adjust the speed and frequency range of the sweeps within Synthmaker.

- Subwoofer Calibrator -- I want to do a few variations on this. Basically, it will play a list of sine wave tones, each for the same duration. The list will continously loop. The duration and the list should be able to be modified within Synthmaker. The idea is that if the tones are at the same level during playback, then the subwoofer level and crossover could be adjusted until they all sound even in the room.


I thought I figured out how to do sweeps, but I haven't been able to get it to work yet. Playing a list of sine wave tones is something that I completely do not understand how to do. Haven't been able to figure that one out at all.

[infuzion]

- Frequency Sweeps -- When this button is pressed, there is a continuously looping frequency sweep from 10Hz to the highest limit at the given sample rate. I would like to be able to adjust the speed and frequency range of the sweeps within Synthmaker.

LFO into Frequency 0-1 (but you have to adjust the range).

[Dell]

- Subwoofer Calibrator -- I want to do a few variations on this. Basically, it will play a list of sine wave tones, each for the same duration. The list will continously loop. The duration and the list should be able to be modified within Synthmaker. The idea is that if the tones are at the same level during playback, then the subwoofer level and crossover could be adjusted until they all sound even in the room.

If you are referring to having everything done automatically, that cannot be done with any software if accuracy is the motive.

[SBMastering]

Of course subwoofer calibration could not be done entirely with software -- I am talking about a tool that would help with the task.

For instance, in Bob Katz's book, "Mastering Audio: The Art and the Science" he references a CD from Rebecca Pidgeon he mastered, where the bass notes play back more or less evenly, so the subwoofer crossover and gain can be adjusted until they all sound even.

Similarly, I would like to have something that plays back a list of frequencies at the same level. It will cycle through the list. Then you can walk over to your subwoofer and adjust the gain and crossover until the notes sound as even as possible with the given acoustic environment and monitoring system.

I'll bit a bit more exact... I will tweak the list, but for a quick example it might play: 30Hz, 120Hz, 40Hz, 110Hz, 40Hz, 100Hz, 50Hz, 90Hz, 60Hz, 80Hz each for the same duration. Then one would walk over to their sub(s) and gain and crossover adjustments until it sounds as even as possible in your room. If you wanted to be exact about it, you could use an SPL meter and look at it while adjusting the subwoofer for maximum linearity. Of course, every acoustic environment and monitoring system is different and will have their limitations, but this will be a tool to achieve maximum linearity in the room and will be a little more accurate than the Bob Katz technique.

I personally have a pair of customized full range Tyler Acoustic D1s and a Bryston Amp in my studio, which don't need a sub... They're scary accurate all the way down to 30Hz, but I would like to have this for mastering engineers who do use subs.

I'm a beginner with Synthmaker, but I've been a professional mastering engineer for 10 years.

I just can't figure out how to make Synthmaker cycle through a list of frequencies and durations...

[Dell]

The majority of measuring software offers the ability to conduct sine wave sweeps with the onboard sine wave generator. If you are not planning to build measuring software with a graph what you are aiming for won’t be very popular to those who want to measure loudspeakers since the graph is the most important part.

The majority of digital audio workstations offer generators as well. Generating a test tone can be done in the digital audio workstation without the means of external software.

As for sweeping frequencies, there was an OSM that offered some means of animation in which the numbers moved automatically from minimum to maximum. It is located in the graphics section. What this means is, you can generate a sine wave sweep from the highest frequency allowed in the sample rate to 0.1 Hz or wherever you choose to stop it.

The house plug-in entitled “Multi Osc” will do exactly what you want since it offers sine, square, saw tooth and so forth. All you would need to do is configure the frequencies to move from beginning to end at a gradual pace. The house plug-in entitled “Envelope Follower” should be able to give you a means of speed control (How fast or how slow the frequencies are swept) based on the release settings.

Cheers!

[infuzion]

Sounds like you need a "sequencer" to automatically run the notes.

[Dell]

This is how you select a fixed frequency. I've explained how to sweep in my previous post.

[SBMastering]

I will work with this tonight and see what I can do. Instead of the knob, it sounds like you're saying I can use the envelope follower to do the same as if you continuously rotated the knob back and forwards, and the envelope follower has a speed control.

[Dell]

I will work with this tonight and see what I can do. Instead of the knob, it sounds like you're saying I can use the envelope follower to do the same as if you continuously rotated the knob back and forwards, and the envelope follower has a speed control.

My post offering a photo is for fixed frequencies whereas my earlier reply is for swept frequencies. You can incorporate both methods providing you think outside the box in your design scheme.

[SBMastering]

I've been scouring the Graphics part of this forum for about two hours, without success, looking for the OSM that sweeps between a minimum and maximum value.

Do you remember anything else about it? Was it posted in the past two years?

[Xtinct]

Why not use the step LFO to set the frequencies and use its speed to set the duration

[SBMastering]

I don't know how to use the Step LFO, and with a little bit of searching on the forum, I still don't know. I'll experiment, perhaps it would help with the list of frequencies I want to scroll through?

There are two problems I'm having: One is a frequency stepper/sequence and the other is a frequency sweeper. I'm still missing something.

[infuzion]

Have you gone though the tutorials yet? http://www.synthmaker.co.uk/dokuwiki/do ... :tutorials

[Xtinct]

Heres a very simple Freq sweep as a starting point

Simple Sweep.osm

(31.36 KiB) Downloaded 101 times

Hope it helps

[Xtinct]

And an even more simple Freq stepper

Simple Freq Stepper.osm

(28.94 KiB) Downloaded 110 times