On Monday, Make Believe Studios and Metric Halo launched the Philly DI, a free emulation of the Sigma Sound Studios DI hardware direct input box.
Philly DI is a 64-bit release for macOS (AU, VST2, VST3, AAX) and Windows (VST, AAX).
Sigma Sound Studios founder Joe Tarsia made the original Sigma Sound Studios DI.
The hardware unit is a general-purpose DI for recording keyboards, bass and guitar, of which only 50 were ever made, and sold out almost instantly.
It became prized in particular for the results it could achieve on bass and guitar.
Make Believe Studios got their hands on one of those rare units and created the Philly DI, which is intended to be a faithful emulation of the original hardware DI.
Thanks to its two integrated effects, the emulation can provide a clean boost to add presence to your DI signal and add some old-school flavour.
The Philly DI has a level-compensated Drive control. When Make Believe Studios’ Rick Carson demoed a bass guitar track on the Philly DI, he noted that the Drive can add some saturation to the low end, giving it a ‘60s sound.
There is also an integrated Compressor, which Carson said you can use to make the tone stand out in a mix by bringing the high frequencies forward, while also retaining a full sound.
If you push both the Drive and Comp together, then the Comp also supposedly emphasises the low-end dirt that the Drive provides.
Make Believe Studios set up the Philly DI with these two effects to reproduce how Sigma Sound Studios used the original unit.
The Drive was included to set the level of gain that the instrument signal hits the DI’s transformer stage with.
Meanwhile, the comp was included to replicate the levelling amp that the studio always included in the signal chain after the DI. This levelling amp was used not only to set the level but to add some flavour to the signal before sending it to the console.
I have to say I’ve only ever used a hardware DI, and it hadn’t occurred to me to use a software solution for it.
But with the Drive and Compression parameters here, I could definitely see how the Philly DI would be handy to impart some old school flavour and grit to your captures.
EDITOR’S NOTE: Several BPB readers who tested Philly DI (read all about it on our community page) reported that they couldn’t hear any difference when using the plugin in “clean” mode. I also tested the plugin and the effect is definitely very subtle (or even non-existent) until you apply the Drive and Comp knobs. Still, I see potential for using Philly DI on bass and guitars with added drive and compression.
Sign up for the Metric Halo mailing list on the product page to score the freebie. After that, Metric Halo should instantly contact you with an email that includes a link to the zipped installer files.
Download: Philly DI (FREE – email required)
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Last Updated on May 8, 2025 by Tomislav Zlatic.
