Metal Marshmallow Pro's Subsonic Frequency Response
November 8 2023
A few people have asked recently about Metal Marshmallow Pro's ability to record very low frequencies below the range of human hearing. This is difficult to measure for several reasons. The initial challenge is finding something that can drive the microphone at just a few Hz. Second, standard audio hardware typically attenuates very low frequencies, and the details are not usually published
Can you attach multiple piezo discs to a single contact mic preamplifier?
August 25 2023
Several people have asked recently whether it is possible to connect several piezo discs in parallel to a single Marshmallow DIY contact mic preamp, as is depicted in the image at the top of this post. Before I get into the details, note that
doing so will not give you stereo or multichannel audio. All of the discs will be combined into a single mono audio channel. If you want multichanne
https://www.youtube.com/watch?v=hcTzLfkdIyA
Raw Materaials
These are the raw materials you will need to make your Aeolian Harp.
Square Section Hardwood
Quantity: 1
Size: 1.5 x 1.5 x 20 inches
Size: 40 x 40 x 400 millimeters
Price Each: 13.98 USD
Cut Into:
End Blocks
Quantity
Update: We now offer a Phanotom Powered version of the DIY preamp. That one was optimized for this purpose and will have slightly better performance than the one described in this article. This artilce is left here for informational purposes, but if you need a phantom powered preamp, just get the new one intead of building this circuit yourself.
Several people have asked me recently if the Ma
Humans can hear sounds up to about 20kHz for children and 16kHz for adults. Sounds with a higher frequency than this are considered ultrasonic. Many microphones can easily hear ultrasonic frequencies. But what about Metal Marshmallow contact mics, how high can they hear?
Theoretical Limits
The theoretical upper limit of the frequency range of each Metal Marshmallow microphone is listed below
This Limited Warranty applies to all Metal Marshmallow branded products, and only those products. These are Metal Marshmallow II, Metal Marshmallow Pro, Marshmallow DIY, and Marshmallow DIY kit.
What does this limited warranty cover?
This Limited Warranty covers any defects in material or workmanship under normal use during the Warranty Period. During the Warranty Period, Metal Marshmallow
Over the years, several people have asked me if they can plug a Metal Marshmallow contact microphone directly into a guitar pedal. The issue is that Metal Marshmallow outputs a line-level signal, whereas guitar pedals are designed to accept input from a guitar, which is an instrument-level signal. In general, line-level is higher than instrument-level, so will this overload the pedal?
Microph
I normally use poster putty to stick contact mics to surfaces. I recently hung a Metal Marshmallow Pro to my front door for about a week using this putty, and it showed no signs of loosening.
In situations where the putty does not stick well to the surface, I will use it in conjunction with double-sided tape. I will put a layer of tape, a layer of putty, another layer of tape, and then the m
A quick web search reveals many AI-written posts about contact mics with clickbait titles. Such posts claim that all contact micropohones are just piezo discs soldered onto guitar cables, and only differ in their casing. These sites then typically go on to 'review' some of the cheapest contact mics available, which are in fact just piezo discs soldered onto guitar cables. Of course, each review
In a previous post I discussed some of the common problems with DIY contact mics. I showed how to get better bass response. In this article, I will address one of the other main problems — hum.
The issue is that DIY contact mics tend to act as little antenneas that pick up electromagnetic radiation that is emitted by other electrical devices and by AC power generally, and which permeates vi
