HD800 Family Technical Measurements including JAR and Jmod

Technical Measurements
HD800, HD800-JAR, HD800-Jmod,
HD800S, HD800S-JAR,
HD8XX

The HD800 family

Back row left to right: HD800S-JAR, HD800-JAR, HD800-Jmod
Front row left to right: HD800S, HD800, HD8XX

HD800 and HD800S and HD8XX are stock, no modifications

HD800S-JAR and HD800-JAR

Modifications by Jupiter Audio Research (JAR)

Listening Evaluation setup

Many immersive sessions occurred with this component collection. HD800-JAR and HD800S-JAR are most impressive modified versions. I now have my own HD800-JAR (43K SN) which continues to provide greatly satisfying recreational listening. HD800-JAR are a very high degree of fit for my personal preferences and my overall favorite version of HD800 family at this point in time.

Data collected as follows:

Coupler:


Mr BlockHead™ flat plate coupler
density similar to average human head 1.08 g/cc
width consistent with average human head 15.25 cm
Headphones carefully positioned on flat plate coupler.


ACO Pacific 7052SYS microphone


Mr BlockHead is mounted on a high mass lighting stand to minimize externally induced vibrations.

Analyzers:

Klippel QC analyzer
Furman SP-20A headphone amp


ARTA analyzer
RME FireFace UC audio IO
Schiit Magni Heresy amp

Calibration:
Brüel & Kjaer 4231 mic calibrator
Fluke 189 DMM

Notes about the analyzer graphs

1) frequency response is not compensated in any way. Data can be exported such that others may use their favorite compensation methods.
2) rub+buzz is a measure of all that remains when fundamental and harmonics are removed. It is sort of an acoustic crap factor.
3) impedance measurements are often noisy and unreliable below 0 dBu in normal environments outside an anechoic chamber or very well controlled sound space. Every electro-acoustic transducer can transform electricity to sound (speaker) and sound to electricity (microphone.) They are usually optimized for one or the other but still can function in reverse. To avoid outside influences impedance is typically measured with a sine sweep of between 0 and +10 dBu. It is a balancing act between outside influence and analyzer input level of which there are more considerations than will be discussed here.
4) rub+buzz below 40 dB SPL is inconsequential
5) measurements were acquired in rapid succession to achieve very stable analyzer system performance. Calibration drift was minimal, background noise at a constant minimum, position of coupler in the room stable, etc. Great care taken to obtain consistent results across the multiple headphones measured.
6) room ambient noise was < 28 dBA, < 35 ~ 37 dBC.

Index
post 1 – setup pictures, data acquisition methods, general notes, index
post 2 – Frequency Response graphs
post 3 – CSD graphs
post 4 – Distortion graphs
post 5 – 30 Hz square wave response
post 6 – 300 Hz square wave response
post 7 – Klippel rub & buzz graphs
post 8 – ARTA pir files part 1
post 9 – reserved for additional data
post 10 – reserved for additional data and/or corrections

 

Frequency Response graphs

HD800 family

Most of the differences are between 5 and 7 KHz with the exception of HD8XX which deviates considerable over the entire spectrum. A very obvious alternative tuning. The HD8XX has many fans for this alternate tuning. I am definitely not one of them.

Frequency response deviation vs headphone location on flat plate coupler

Horizontal positioning of headphones is easy to tightly control. Vertical positioning is a bit harder. This graph demonstrates measurement deviation for the same headphone when vertical position deviates ±3 mm. Differences are minimal.


Observe much greater measurement deviation when vertical position deviates ±6 mm

All headphones measured were carefully positioned to within ±1mm vertical location deviation.

All versions of HD800 measured had closely matched Left – Right frequency response

HD800 L-R frequency response


HD800-JAR L-R frequency response


HD800-Jmod L-R frequency response


HD800S L-R frequency response


HD800S-JAR L-R frequency response


HD8XX L-R frequency response

 

CSD graphs

HD800 CSD


HD800-JAR CSD


HD800-Jmod CSD


HD800S CSD


HD800S-JAR CSD


HD8XX CSD


HD800 HD8XX CSD animation

Observe considerable lengthening of HD8XX decay time below 1000 Hz. This gives the HD8XX a feeling of greater bass and mid frequency energy. To my ears this also results in low mids and mid frequency muddiness. Does not fit my personal preference profile.

HD800 HD800-JAR CSD animation

JAR modifications even out the spectral decay above 5 KHz. Resonances don’t disappear but are better behaved and consistent over the higher spectrum.

HD800 CSD animation of all six versions

 

Distortion graphs

HD800 Distortion


HD800-JAR Distortion


HD800-Jmod Distortion


HD800S Distortion


HD800S-JAR Distortion


HD8XX Distortion

 

30 Hz square wave response

Observations on 30 Hz and 300 Hz square wave response are similar. See 300 Hz for detailed commentary.

HD800 30 Hz square wave -15dBu


HD800-JAR 30 Hz square wave -15dBu


HD800-Jmod 30 Hz square wave -15dBu


HD800S 30 Hz square wave -15dBu


HD800S-JAR 30 Hz square wave -15dBu


HD8XX 30 Hz square wave -15dBu

 

300 Hz square wave response

HD800 300 Hz square wave -15dBu

Original generation behavior. Note higher frequency ring which dampens after 0.9 mS.

HD800-JAR 300 Hz square wave -15dBu

JAR mod reduces ringing and shortens damping time to approximately 0.7 mS
This tightens response to transients.

HD800-Jmod 300 Hz square wave -15dBu

Jmod has a longer ringing time but this may be deterioration of drivers which have seen nearly a decade of long session hours.

HD800S 300 Hz square wave -15dBu

800S has an improved response with less ringing overall.

HD800S-JAR 300 Hz square wave -15dBu

JAR mod improves the response further with less ringing overall.

HD8XX 300 Hz square wave -15dBu

It was necessary to change vertical scale on the oscilloscope for HD8XX measurement.
Note the rise time is considerable slower than the other five HD800 versions. This will slow transient response time, possibly dulling the sound of percussive sounds.

 

Klippel rub & buzz graphs

Rub & Buzz is the black trace in Chart 1 (upper left).

HD800 rub & buzz 90 dB SPL


HD800-JAR rub & buzz 90 dB SPL


HD800-Jmod rub & buzz 90 dB SPL

Jmod is flagged as fail due to reversed wiring changing the headphone polarity. This was for some polarity experiments and I never changed the wiring back. Instead I use a VST process that includes polarity reversal when listening.

HD800S rub & buzz 90 dB SPL


HD800S-JAR rub & buzz 90 dB SPL


HD8XX rub & buzz 90 dB SPL

 

ARTA pir files

ARTA pir files saved from data acquisition are attached in this and the next posts. These are not compensated in any way. ARTA users may import these data files and change measurement parameters, utilize any favorite compensation curves, etc. to obtain different views of the measured data.

 

reserved 9/10

 

reserved for additional data and/or corrections.