EEVblog #571 - Sennheiser EW100 G3 Wireless Microphone Teardown

[EEVblog]

What is inside one of the best quality wireless microphones on the market?
http://amzn.to/LAA8Yq
Dave takes a look inside the Sennheiser EW100 G3 SK100 Bodypack Transmitter and the EK100 Diversity Receiver.
Datasheets:
http://www.analog.com/static/imported-files/data_sheets/ADF4116_4117_4118.pdf
http://www.onsemi.com/pub_link/Collateral/SA575-D.PDF
http://www.xie-gang.com/BH4127.pdf

[rolandpenplotter]

Thank you Dave I'm interested in these since our local church has issues with other brands (probably analogue mics).

PS: ... FIRST

[ceecrb1]

Thank you Dave I'm interested in these since our local church has issues with other brands (probably analogue mics).

PS: ... FIRST

I cannot recomend recomend the sennheiser evolution series enough.
These ew100's are actually the lowest "quality" (really featured) of the family and they are great!
I´ve spent all my adult life using Ew's from the first generation (that used 9v batteries) to the G2s and now G3s (Generation3) and had little to no issues... and I´ve really put them though a lot of stress... eg using MANY channels at the same time, over long distances etc etc and NEVER had any real isssues.

BE AWARE.. 99.9999999999999999999999999999999999% of "new" Sennheiser wireless mics on ebay ARE copies. Only buy from authorised dealers. There are so many stories of people sending defective mics back to sennheiser for repair to find out that what htey thought was "real".. isnt. I've even read on a technitians forum that senny repair techs have been fooled right up to the moment they open them up... the copies are THAT good. (except in quality).

The only thing these lack in is that the kit capsule. Try to budget extra to be able to not take the cheapest option. but if you have to, it will still work better than most brands!

[rolandpenplotter]

Thank you Dave I'm interested in these since our local church has issues with other brands (probably analogue mics).

PS: ... FIRST

I cannot recomend recomend the sennheiser evolution series enough.
These ew100's are actually the lowest "quality" (really featured) of the family and they are great!
I´ve spent all my adult life using Ew's from the first generation (that used 9v batteries) to the G2s and now G3s (Generation3) and had little to no issues... and I´ve really put them though a lot of stress... eg using MANY channels at the same time, over long distances etc etc and NEVER had any real isssues.

BE AWARE.. 99.9999999999999999999999999999999999% of "new" Sennheiser wireless mics on ebay ARE copies. Only buy from authorised dealers. There are so many stories of people sending defective mics back to sennheiser for repair to find out that what htey thought was "real".. isnt. I've even read on a technitians forum that senny repair techs have been fooled right up to the moment they open them up... the copies are THAT good. (except in quality).

The only thing these lack in is that the kit capsule. Try to budget extra to be able to not take the cheapest option. but if you have to, it will still work better than most brands!

Thank you so much for your kind advice. I cannot envisage buying church equipment from eBay; I just can't see them agreeing to that.

[EEVblog]

The only thing these lack in is that the kit capsule.

Sound quality seem excellent to me, matches my other mics quite nicely.

[mikeselectricstuff]

I think that "distributed filter" is just a test-point for a co-axial pogo-pin probe

[ceecrb1]

IF I´m feeling generous, I may mail-bag you a spare MKE2 capsule then.... 
I "came into ownership" of a few (legaly)
The difference is quite large... in sound and price!

While the kit capsule is NOT bad and very usable... Obviously its not a bad thing to improve if improvements can be made.

[SteigsdB]

Hi Dave, great and interesting video as usual!

What is inside one of the best quality wireless microphones on the market?

I just wanted to point out that, while the G3 is a great system at its price point, "best quality..on the market" might be a bit of a stretch.

In the film and television production world they're generally considered 'entry' level units.  The 'best in class' units (staying with the battery powerable units) would be the SM*, UM* and 411 series from Lectrosonics or most of the offerings from Zaxcom. 

Just wanted to throw that out there as someone who works with these systems daily.

Your mileage may vary, some assembly required.

PS +1 on the mickey 2's being a great lav.  Sanken COS-11's are another great mic in that family.

[Lightages]

The only thing these lack in is that the kit capsule.

Sound quality seem excellent to me, matches my other mics quite nicely.

UHF is not inherently better than VHF. Also I agree that the included microphones are not the best.  Try the mic that came with the Audio Techinca system. IMHO they sound better with the G3.

[RupertGo]

Great blog - loving the RF bonanza at the moment. From 10 kW of VHF to a few milliwatts of UHF in the space of a week - I'd send my WWII vintage HF Wireless Sets Number 19 for a mailbag teardown candidate, if the postage to Oz wouldn't bankrupt me...

Wireless microphones cause some headaches for spectrum regulators and designers. They have to be analogue - you can't have any delay for live music shows - and they have to have lots of channels, plus you can't accept any level of interference from other services and size/power issues means they really have to be in bands where lots of other things already live (usually in the middle of the TV UHF band, where the other things can be really quite brutish). Particularly problematic for those who try and do white space RF, which tries to slot itself into unused parts of bands allocated to other services. Small, susceptible, hard to detect and very, very mobile.

The interference rejection is one reason why there's so much filtering and good solid RF engineering in those things. I'd love to see a circuit or some RF performance specs for them.

[NiHaoMike]

Wireless microphones cause some headaches for spectrum regulators and designers. They have to be analogue - you can't have any delay for live music shows

It's possible to design digital for very low latency nowadays. Even common 802.11n can do well under 1ms round trip. The latency can be even lower for a system designed to do one way streaming of HD audio.

[jpenn]

The only thing these lack in is that the kit capsule.

Sound quality seem excellent to me, matches my other mics quite nicely.

UHF is not inherently better than VHF. Also I agree that the included microphones are not the best.  Try the mic that came with the Audio Techinca system. IMHO they sound better with the G3.

IMHO UHF is a little less prone to interference. Of course a lot depends on the quality of the T/R. Also for normal speech on YouTube you don't really need a high quality mic. I have two different Audio-Tech lapel mics. Both are lower end mics and you would have to listen close to hear any difference in them.   Also just the fact you are using a lapel mic even it is a cheap one, you will sound better then 90% of YouTubers out there. You could have a video that is visually stunning but if the audio sucks the video sucks.
John

[Psi]

Yep, Sennheiser make awesome stuff.

I saved up and chose some Sennheiser headphones from the local audio shop when i was 15 for ~$70 (quite a bit back then). 
They just sounded awesome and the lasted 10+ years, eventually failing due to the padding falling apart from use and the cable breaking a few times when i stood up with the cable hooked on something.

Now i have some Sennhesier PC360 which really are sex on a stick for sound quality and have a mic for PC gaming.

There's a lot of fake Sennhesier sub $100 headphones floating around on ebay and other sites. So yeah, as someone already said, if you want sennheiser make sure you get a legit version.

I would recommend anyone buying headphones to try out some Sennheisers in a shop and be prepared to pay ~$200 for the good stuff. The genuine sub $200 Sennheiser stuff is still good but it lacks the WOW factor that their $200+ headphones have. The quality shifts from retail to prosumer between $100 and $200 and then approaches studio quality around $600.
But the prosumer stuff really is good enough

[tchicago]

Notice the unusually large 4MHz crystals or oscillator hybrids on both devices. These most likely generate the frequencies that are later used to synthesize the RF, so they are high quality and most likely temperature compensated.

You also mentioned the "charger" circuitry driven by the LT chip. But there is nothing to charge: the device uses the non-rechargeable batteries. So those are most likely are just the DC2DCs.

It is also pretty cool to see all the RF inductors are off the shelf, so the RF part does not need any manual mechanical tuning during the manufacturing. The older TVs have their RF cans full of ugly looking custom made inductors that had their shape twisted by the technician while tuning and then fixed with some glue. That does not mean Sennheiser did not need any tuning or calibration at all, it probably needed much less of it due to more stable components. And the rest of calibration is done via varicaps and stored somewhere in EEPROM. All automated on the bed of nails, with no white bearded guru sticking out his tongue at the right angle

[Psi]

You also mentioned the "charger" circuitry driven by the LT chip. But there is nothing to charge: the device uses the non-rechargeable batteries. So those are most likely are just the DC2DCs.

Rechargeable AA cells.
Many devices using AAs have an selectable option for both dry cell and rechargeable.

Probably enabled in the menus somewhere (maybe hidden) for customers who want a charging station setup.

[SteigsdB]

They have to be analogue

The Zaxcom stuff is digital.

Years ago there was a company called x-wire that made digital wireless systems for guitars. Some artists went so far as to have capacitors added to the Tx wire to mimic the loss (sound) from the 50' cables they were previously using.

[ram]

i really love this kind of communication stuff.i look forward to watch more communication stuff.
this give some insight about this kind of stuff
dave  i really thank you

[EEVblog]

You also mentioned the "charger" circuitry driven by the LT chip. But there is nothing to charge: the device uses the non-rechargeable batteries. So those are most likely are just the DC2DCs.

The side contacts are for using rechargeable AA's. It can use either type.

[ceecrb1]

Just use rechargable batteries and this:

http://en-us.sennheiser.com/l-1039-10

These are more use to (for example) a theater where there are day in day out shows.. so at the start of the run an actor will be assigned a microphone or wireless in-ear receiver (which has the same form factor) which they are to use every show.
Trust me... new batteries EVERY show (which is not only best practice, its only practice!) creates mounting costs very rapidly!

[Rasz]

The only thing missing form this great teardown is a dive into modulation/data format used.
Something like $10 RTLSDR + http://www.hdsdr.de should do the trick

[calzap]

Notice the unusually large 4MHz crystals or oscillator hybrids on both devices. These most likely generate the frequencies that are later used to synthesize the RF, so they are high quality and most likely temperature compensated.

There is a pretty good view of a "can" at 17:40 in the video.  A snapshot is below.  Am I right in assuming this is a 4 MHz oscillator?  What is the brand?  Matsushita?

Mike in California

[greatal]

that NXP LPC2364fet100 is just amazing
it is like you have a powerful dragon in your pocket
up to 70 general purpose I/O pin!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
72 MHz
USB(those side contacts maybe some usb)
I2C I2S
Ethernet!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! RMII wow
SPI(MMC ...)
RTC?

http://www.nxp.com/products/microcontrollers/arm7/LPC2364FET100.html

[Stonent]

I'm surprised they spun a second board for the display and interface when they appear to be about 90% the same.

[JackOfVA]

Since Dave has a spectrum analyzer, perhaps a follow up video with some reverse engineering of the RF modulation would be in order. 

[DutchGert]

Since Dave has a spectrum analyzer, perhaps a follow up video with some reverse engineering of the RF modulation would be in order.

Yes, that would be very nice. Just to give some insight in what kind of techniques they use

[Axles]

Notice the unusually large 4MHz crystals or oscillator hybrids on both devices. These most likely generate the frequencies that are later used to synthesize the RF, so they are high quality and most likely temperature compensated.

There is a pretty good view of a "can" at 17:40 in the video.  A snapshot is below.  Am I right in assuming this is a 4 MHz oscillator?  What is the brand?  Matsushita?

Mike in California

I would probably say that's a smd filter from Mini Circuits

[calzap]

Notice the unusually large 4MHz crystals or oscillator hybrids on both devices. These most likely generate the frequencies that are later used to synthesize the RF, so they are high quality and most likely temperature compensated.

There is a pretty good view of a "can" at 17:40 in the video.  A snapshot is below.  Am I right in assuming this is a 4 MHz oscillator?  What is the brand?  Matsushita?

Mike in California

I would probably say that's a smd filter from Mini Circuits

You could be right, but their small devices in all the pics that I have seen use a simple MCL logo.  Crystek Microwave also came to mind, but I can't find any pics of their devices that use the logo seen on the device in the video.

Mike in California

[beaker353]

Don't count analog RF mics out yet.  I would venture to guess that 90% if not more of the transmitters you will find in large scale productions will be analog. Digital still still has a lot of hurdles to overcome before you find the big boys trusting their reputation on digital. Latency is a factor for sure, but people forget about how truly robust analog transmissions are to interference especially when wireless mics are sharing the same spectrum as broadcast TV here in the US. Analog RF mics will start to give a seasoned engineer (the console operating kind) subtle warning signs that there is something nasty afoot usually long before all hell breaks out. Digital RF mics have this bad habit of going from perfectly fine to nothing when the spectrum gets bumpy. (There are few things worse to a mix engineer to have your lead mic start cutting in and out while the talent is on stage and you are powerless to do anything about it from behind the console.) You can add error correction and a host of other technologies to help out the digital signal , but this adds even more latency to a system. Speaking of latency, you have to keep in mind that there is a finite window you have to stay in before you start effecting the performance on stage. Many on-stage performers wear in-ear monitors instead of traditional wedge stage monitors. They hear themselves through a combination of the in-ears they are wearing, and the acoustic conduction up their jaw to their ear. You start adding too much latency to the in-ear signal with digital RF transmissions, digital console, and other digital processing gear and you start creating a crazy comb filter problem for the poor performer. From some experimentation I'm done on stage with female vocalists, 6ms seems to be about the point in which they start to have a hard time maintaining pitch. This is one reason that even though an analog console now can cost 4 times as much as its digital brother, you will still find plenty of analog desks in use for monitors just to keep this  latency down.  We are in the process of a 250k upgrade to our show wireless systems, and you will not find any digital transmission gear on our list...

-EM

[atw60444]

Beaker, that was an interesting insight thank you. And some singers can sing in pitch? That's good to know too

[beaker353]

Beaker, that was an interesting insight thank you. And some singers can sing in pitch? That's good to know too

It has been known to happen from time to time...

-EM

[SeanB]

With Autotune even I can sing properly. Without the cats leave the vicinity and windows are in danger.

[CJWarlock]

I was using this Sennheiser transmitter with lapel mic for a few times in the past so I had an ocassion to test it. It really is a hell of a wireless mic and works good even in the environment filled with diffrent RF signals that may cause problems on other wireless mic systems. I was using it together with the stationary receiver (EW500 if I remember correctly). Pretty reliable in my opinion. And the construction quality and overall feeling of the lapel mic transmitter really is impressive.

On the other hand, I had some problems with the handheld transmitter (EW100 G2 IIRC) when PA-ing a small event in the center of the city. Battery level (in the handheld mic) and RF signal level were 100% OK and it still would weaken or break transmission for a few tens of ms every few seconds. Tried different channels. I guess it there could be some strong interferences from the railway station (100 m away) or the transmitter could be somehow damaged. I was doing only a few PA-ings with that set and it wasn't mine so I didn't checked that case deeper. However I'd be happy if someone would just by the way share some knowledge about such behavior of EW100 G2 handheld transmitter.

[sq6rdy]

Small LT chip marked LTPG, near charging connector is step-up 1A 3MHz DC/DC converter (LTC3401).

There is a pretty good view of a "can" at 17:40 in the video.  A snapshot is below.  Am I right in assuming this is a 4 MHz oscillator?  What is the brand?  Matsushita?

Mike in California

This component is made by Murata. It's not oscillator, probably some kind of SAW filter or similar device.

[NiHaoMike]

Many on-stage performers wear in-ear monitors instead of traditional wedge stage monitors. They hear themselves through a combination of the in-ears they are wearing, and the acoustic conduction up their jaw to their ear. You start adding too much latency to the in-ear signal with digital RF transmissions, digital console, and other digital processing gear and you start creating a crazy comb filter problem for the poor performer. From some experimentation I'm done on stage with female vocalists, 6ms seems to be about the point in which they start to have a hard time maintaining pitch. This is one reason that even though an analog console now can cost 4 times as much as its digital brother, you will still find plenty of analog desks in use for monitors just to keep this  latency down.  We are in the process of a 250k upgrade to our show wireless systems, and you will not find any digital transmission gear on our list...

Wouldn't it make more sense to do the feedback locally instead of sending it out to the console and back? Also, FPGAs can do mixing, effects, and more with very low latency, down to a few samples. Main problem is that it's not trivial to deal with clock skew, but that can be prevented with a master clock.

[komet]

Wouldn't it make more sense to do the feedback locally instead of sending it out to the console and back?

The monitor signal contains other channels as well as your own in order to be able to keep in tune and time with the rest of the band. Also I think it is post-EQ. Digital is definitely not better. A low latency is far mor iportant for monitoring than low noise.

[eceforge]

So here's my question -- where do you find small little LCD modules like that...I've looked in the likes of mouser and digikey and the few options that there are seem to almost always be out of stock. Anybody have a good source? I tried searching for a few of the numbers that were shown in the video on the back of the LCD, but I didn't turn anything up. Obviously doesn't have to be an exact match for that LCD just something in the same size range. The standard 16x2 character LCDs are always too big and clunky with their associated backpacks for small projects.

[bdumaguina]

Hello,

I understand this is an old thread. But this is one of the best teardowns of the Sennheiser EW 100 G3 series Tx and Rx.

I've handled these things for a while now and had my fair share of DIY repairs from replacing antennas, cleaning out corrosion that sometimes build up from talents' sweat seeping into the circuit board (I work in the film industry), swapping out a good RF board from a defunct unit to a unit with a problematic RF board, etc.

This time around I'm getting an unusual problem on the Rx. Tx is good - I'm getting audio in with a lav mic - and if I paired the Tx with a different Rx I can get audio to pass through.

On the problematic Rx - I'm getting good RF activity - it's rock solid. I can also "see" AF activity - BUT - when I connect the Rx to a mixer or recorder via the 3.5mm jack - I'm not getting any signal/audio.

I don't think the physical connection (the 3.5mm jack) has any problem - anywhere else I can look? Which of the mentioned chips in the video could be responsible for the audio output on the 3.5mm jack?

Thanks,
Bryan D.