Ouch, this was way more serious than I was expecting, but I kept reading through the several parts. Totally out of my area but quite well explained. This was a nice little venture into electronics hacking.
Reprogramming a Sennheiser Microphone
11–20 of 23 posts
Re: Reprogramming a Sennheiser Microphone
#12Thanks for this. Good advice at the end plus a link to an unrelated but equally interesting hardware debug/reverse engineer: Lessons for aspiring reverse engineers Spend a few hours/days reading before you start doing. Prior knowledge helps. You'll get better at reverse engineering as you do it more. Code shape is recognizable. SPI drivers all look the same, I2C drivers all look similar, circular buffers all look the…
> ...Take notes as you try/figure out things, since your "trying things" binary will quickly become an unmanageable mess and you'll forget things.
Worth to mention also that Version Control of the analysis artifacts helps in tracing your way forward. It also helps in trying out ideas to refine your understanding.
Re: Reprogramming a Sennheiser Microphone
#13Throwaway for some obvious reasons, but I work at Sennheiser and I think this is awesome! Personal opinion, and not speaking for the company.
A small disclaimer: operating modified RF devices can, in some jurisdictions and depending on the impact of your modification, put you in contradiction of the law.
From the manual: "Your SKM 3072-U hand-held transmitter can be operated on one of up to 32 different frequencies. These frequencies and their sequence are pre-programmed by the factory and must only be changed by your Sennheiser distributor who has the required specialist equipment."
You may be surprised, but I just checked with some colleagues, we still have the software (SePT.exe) around as well as the service cable. :) I am not sure the last time we performed that service though!
Re: Reprogramming a Sennheiser Microphone
#14Throwaway for some obvious reasons, but I work at Sennheiser and I think this is awesome! Personal opinion, and not speaking for the company. A small disclaimer: operating modified RF devices can, in some jurisdictions and depending on the impact of your modification, put you in contradiction of the law. From the manual: "Your SKM 3072-U hand-held transmitter can be operated on one of up to 32 different frequencies.…
I like Sennheiser because they make at least some stuff still in Europe (vs. many competitors who pretty much live off of made in china copies of classic designs). It's just weird that Sennheiser is very quiet about it, they used to have a "MADE IN GERMANY" on a lot of stuff, directly silk-screened or molded into cases etc. -- this has disappeared. At first I suspected that production for these products was offshored, but it wasn't (still says Made in Germany in the fine-print). Kinda odd.
Re: Reprogramming a Sennheiser Microphone
#15Throwaway for some obvious reasons, but I work at Sennheiser and I think this is awesome! Personal opinion, and not speaking for the company. A small disclaimer: operating modified RF devices can, in some jurisdictions and depending on the impact of your modification, put you in contradiction of the law. From the manual: "Your SKM 3072-U hand-held transmitter can be operated on one of up to 32 different frequencies.…
What is the RF output power of these devices?
Re: Reprogramming a Sennheiser Microphone
#16Throwaway for some obvious reasons, but I work at Sennheiser and I think this is awesome! Personal opinion, and not speaking for the company. A small disclaimer: operating modified RF devices can, in some jurisdictions and depending on the impact of your modification, put you in contradiction of the law. From the manual: "Your SKM 3072-U hand-held transmitter can be operated on one of up to 32 different frequencies.…
What is the RF output power of these devices?
According to the specification, 30 mW[0]
[0]https://assets.sennheiser.com/global-downloads/file/12003/Sp...
Re: Reprogramming a Sennheiser Microphone
#17Throwaway for some obvious reasons, but I work at Sennheiser and I think this is awesome! Personal opinion, and not speaking for the company. A small disclaimer: operating modified RF devices can, in some jurisdictions and depending on the impact of your modification, put you in contradiction of the law. From the manual: "Your SKM 3072-U hand-held transmitter can be operated on one of up to 32 different frequencies.…
Hi, thats amazing! I was trying if it would be possible to find the software or the cables somewhere hidden on web. But it's looks like there is nothing. This was actually the motivation for the blogpost in case someone want to the same thing, so he can get the informations.
Re: Reprogramming a Sennheiser Microphone
#18Throwaway for some obvious reasons, but I work at Sennheiser and I think this is awesome! Personal opinion, and not speaking for the company. A small disclaimer: operating modified RF devices can, in some jurisdictions and depending on the impact of your modification, put you in contradiction of the law. From the manual: "Your SKM 3072-U hand-held transmitter can be operated on one of up to 32 different frequencies.…
I like Sennheiser because they make at least some stuff still in Europe (vs. many competitors who pretty much live off of made in china copies of classic designs). It's just weird that Sennheiser is very quiet about it, they used to have a "MADE IN GERMANY" on a lot of stuff, directly silk-screened or molded into cases etc. -- this has disappeared. At first I suspected that production for these products was offshored…
Complete guess here but I would suspect that means some items are made in Germany and some are made in China or elsewhere (meaning, even the same model may be produced in both locations). If they are printing "MADE IN GERMANY" directly on it then it will be obvious which ones aren't, because they would lack the print. And that would likely degrade the perceived quality of those not made in Germany vs those that are. And Sennheiser doesn't want you to think that some of their items are built with better quality than others.
Of course, people can look at the fine-print and determine where it was made. But that's a lot less obvious than the silk screened badge not being there.
Re: Reprogramming a Sennheiser Microphone
#19Earlier quoted context omitted.
> Weird-looking constants mean things. The weirder the number, the more meaning it probably carries Curious what this is suggesting?
Depending on what device you're reverse-engineering, the random integers can be: * Hard-coded encryption keys * Hard-coded IP addresses (remember, IPv4 addresses are 32 bits long, which is convenient for many embedded CPUs and even some MCUs) * Hard-coded (instead of random) hash salts ...and generally all manner of things that shouldn't have been hard-coded. That's not to say all constants are bad, but I can see 0xF…
Unless it's 0x5f3759df, which must be the legendary fast inverse square root ;-)
https://medium.com/hard-mode/the-legendary-fast-inverse- square-root-e51fee3b49d9
Re: Reprogramming a Sennheiser Microphone
#20just as an aside for I2C devices, if you know the address, then there is often not many choices on what it can be.
https://i2cdevices.org/addresses http://www.coris.org.uk/jdc/Notes/i2c-devices.html