# Optical compression Optical compressors have a slower attack, controlled by light.[^1] However, the average attack time of an LA2A, for example, is 10ms, which is still rather fast.[^2] They have a frequency-dependent attack time[^3] and react based on RMS rather than peaks.[^4] The LA2A is the most famous optical compressor.[^3] The LA3A is similar, but valveless.[^5] These sound great on vocals and bass, especially when doing just a few decibels of gain reduction,[^6] but they can also compress a lot without it being so obvious.[^4] They can, however, be susceptible to pumping if a loud spike is fed into them.[^3] Using RMS compression with lookahead can simulate opto.[^7] [[Kotelnikov GE]]'s Inertia mode is similar to optical compression. [[LALA]] is an LA2A emulation. I like [[Pro-C 2]]'s optical mode. [[MTurboComp]] does an LA2A. Mike Clink, Mark Endert, Tony Maserati, Jim Scott, and Rick Beato[^8] all like an LA2A on bass.[^5] Beato likes an LA2A and acoustic guitar and an LA3A clean guitars.[^8] Serge Tsai and Glen Ballard like the LA2A for how warm and gentle it is on vocals. When pushed, the LA2A can distort nicely, say Joe Chiccarelli and Joe Barresi.[^5] [^1]: [Here are the most used type of compressors today! 🙌 - YouTube](https://www.youtube.com/watch?v=cUTe3PJYFfM) [^2]: [[Mixing with Emotion with Matthew Weiss]] [^3]: [Audio Compressors: VCA, FET, and Other Compression Circuit Types](https://www.masteringbox.com/audio-compressors-vca-opto-fet-compression-circuit-types/) [^4]: [Four Types Of Compression And Why You Need Them All - YouTube](https://www.youtube.com/watch?utm_source=pocket_mylist&v=oIDvjCmaq-0) [^5]: [Classic Compressors](https://www.soundonsound.com/techniques/classic-compressors?utm_source=pocket_mylist) [^6]: [4 Types of Compressors Explained (+ Mix Tips) — Pro Audio Files](https://theproaudiofiles.com/types-of-compressors/?utm_source=pocket_mylist) [^7]: [[Level Rodeo]] pg. 35 [^8]: [How The Pros Use Compression - Audio Compression Instruments and Mixes - YouTube](https://www.youtube.com/watch?v=7oOmX3JHwtE) [^9]: [What are the different types of compressors?](https://audiohertz.com/2017/08/07/what-are-the-different-types-of-compressors/?utm_source=pocket_mylist)