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I ALREADY HAVE A PLUGIN/APP THAT MAKES MY HEADPHONES SOUND GREAT, HOW IS THIS ANY BETTER?

Many years ago, we were very excited to see all the options coming to market to tune headphones and we have tested most (if not all) of them personally. Eventually we came to the conclusion that while all of the options available were a step in the right direction, none of them were tailored to what we were looking for.

We wanted each speaker driver to match each other as closely as possible, something not achievable using averaging which is what many of the available solutions for headphone tuning plugins/apps use. So, we sent a set headphones out to be “calibrated” and received our individual profile for the specific software host offering the service. The results were closer to what we desired, but still not performing at the level we knew was possible.

The main issue we had with our freshly calibrated headphones wasn’t driver matching, that was done very well. It had to do with the target curve the headphones were tuned to. Every company offering any kind of headphone tuning is correcting the headphones to a target curve and there is no standard on what the ideal curve is for headphones. This lead us to develop our own headphone reference target curve, focused on the needs of professional audio users.

The final issue we had with the available headphone correction plugins/apps out there has to do with the tools and methods used to create the headphone correction profiles. Some companies simply use a PEQ under the hood to correct the frequency response of headphones and ignore all considerations to phase. Others solutions do take phase into account with their headphone optimization, but only with the EQ they are using to correct the drivers frequency response. Using a linear phase equalizer to tune headphones is an ideal solution for the application, that is what we do at Sonic Standards with FIR filters, but using linear phase equalization for correction only ensures the existing phase response of the speaker driver is not impacted. No consideration or correction is applied to the drivers natural phase response. The results of our research have shown that not compensating for a drivers natural phase response is missing a step in optimizing the playback performance of most headphones.

THE SONIC STANDARDS TARGET REFERENCE RESPONSE

We worked extensively with audio industry professionals in the music, film, post production and video game fields to develop our headphone target reference response (a.k.a. “curve”). The goal with our curve was to provide headphones a perceived flat frequency response, allowing the listener to trust what they are hearing and make informed decisions without having the “is this right” worry in the back of their mind. With our target reference response refined and accepted by many trusted ears, you can be confident that what you are hearing is truth.

WHAT ABOUT COMPATIBILITY WITH BINAURAL SIMULATION FOR ATMOS, AND THAT ROOM MODELING PLUGIN I’VE COME TO USE ALL THE TIME WITH MY HEADPHONES, AND THAT CROSSFEED PLUGIN I LOVE. CAN THEY BE USED WITH SONIC STANDARDS HEADPHONE CORRECTION?

Yes, yes and yes. This brings up a very important concept with our headphone correction profiles hosted on DSP units. You will need to bypass or remove anything that mixes left and right audio signals AFTER the DSP. If your headphone amp has crossfeed, L/R swap or mono sum features, you need to disable them while listening with our headphone correction on. Otherwise you will be hearing corrected audio coming through speaker drivers that are not compatible with the tuning applied and it’ll likely sound terrible.

So, if you’d like to mix Atmos on headphones, listen to your audio in a room modeling plugin, apply custom crossfeed, mono sum or L/R swap the audio source, that all needs to happen BEFORE the DSP for the headphone correction to work as intended. With that law in place, our headphone correction profiles works perfectly in all of these use cases. Be sure to remove any headphone EQ or tuning built into these plugins/apps as well, otherwise you could be double processing the audio and it will sound terrible.

Final note on this subject. We LOVE crossfeed and our headphone correction profiles do have crossfeed built in as an option for monitoring, but it can be easily bypassed at the DSP. If you are using any “spatial” software for headphone monitoring, you’ll want to bypass the crossfeed we have available in the DSP and let the software (before the DSP!) handle that.

WILL I LIKE THE WAY MY HEADPHONES SOUND AFTER TUNING?

If your ultimate goal is to have headphones that are “reference flat”, as in the headphones are not imparting any (frequency response) voicing of their own, then you’ll really enjoy and trust headphones with our correction applied. Remember, our target reference response is tailored to the needs of audio industry professionals (recording engineers, mixers, mastering engineers, etc.)

With that said, we’ve had a very small number of customers (all of them from the HiFi world) that have become accustomed to how their headphones sound and couldn’t wrap their head around hearing them tuned to our reference response. We get it, they have spent years and years with these cans strapped to their head and their brain has become accustom to the sound. For them we created an additional correction profile (stored in the DSP) that matches the headphone speaker drivers to each other and corrects each drivers phase, but we did not tune the frequency response of the drivers to our target reference response. This correction provides the best coherence possible while maintaining the out of the box frequency response of the headphones. NOTE: This is not a standard offering and needs to be requested by contacting us prior to purchasing a headphone tuning.

CAN I BYPASS THE CORRECTION IN THE DSP?

Yes! We do this ourselves occasionally. Bypassing the tuning to “let the headphones do their thing” and check audio sources for issues that become much more prevalent with the tuning bypassed is a time tested practice in the professional audio world. Every set of headphones has a unique voicing that can be used to identify sonic anomalies in the source. With our implementation of the headphone correction profiles on a DSP, you are never limited to working one way. Listen to headphones tuned, untuned, with crossfeed, without crossfeed, the choice is yours to monitor how you’d like.

WHY DO YOU USE DSPs INSTEAD OF SOFTWARE?

There was a great amount of effort involved in finding an elegant way to implement our headphone correction into users workflows. We first started with software based approaches, using plugins and/or apps to host our headphone correction profiles. While it worked great from a sonic perspective, it was a chore to get audio routing setup for most users and it didn’t have the “plug n' play” usability we desired. With that experience and lessons learned under our belt, we pivoted to processing our headphone correction profiles on dedicated DSP units.

The ease of implementation was greatly improved using DSPs and sonically there were no compromises from the software solutions we had previously used, sounds like we nailed it right!?! Well, yes and no… While we had figured out an elegant way to implement our headphone correction into users work flows, the availability of DSP units suitable for our use case was very limited and very expensive for our application at that time. Move forward a few years and now there are several products on the market that allow us to cost effectively implement our headphone correction profiles for most users. So we’re on DSPs and it’s staying that way for the foreseeable future.

That all said, should you really desire to host our headphone correction profiles on a compatible platform that we do not offer (hardware DSP or software) contact us to see if it’s feasible.

WHAT TYPES OF HEADPHONES CAN YOU TUNE?

Currently we tune over ear and on ear headphones. IEM’s (in-ear monitors) are not currently compatible with our custom measurement system.

LINEAR PHASE FIR FILTERS TO TUNE HEADPHONES, DOESN’T THAT CAUSE TONS OF AUDIO DELAY?

Using linear phase FIR filters does add delay to the audio signal, it is inherent in how they work. That said, we use a blend of FIR filters and standard PEQ to create our headphone correction profiles. If we were to correct the entire audible range with linear phase FIR filters the delay caused would be well over 100 milliseconds, far too much for the majority of our professional users. So, after countless hours of critical listening we eventually found the perfect balance of quality processing with minimal delay. Comes out to be around 10 milliseconds which is unperceivable to most users on playback.

NOTE: If monitoring “live” inputs, say a drummer in the studio wearing headphones using our correction, the cumulative delay of the recording software, AD/DA converters and any additional processing on the system will likely increase the total delay in the audio chain to a point the person recording will not be able to use it. Something to keep in mind while using our headphone correction.