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Lectrosonics announces DCHT dual-channel digital transmitter

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Looks like a great way to make an AES hop to an Amira / other AES enabled cameras.  Throw a couple of AA's and attach one cable, done!

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That is correct - this is full digital and not compatible with SR receivers.  View this as the tip of the spear of the next generation  or tumbleweed pollen if you prefer......

 

 

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Let's talk about DCHT (Digital Camera Hop Transmitter) specs.

Lectrosonics makes 3 digital wireless systems:
DSW System
Encrypted Digital Wireless System using DBa Belt Pack Transmitter 
ANALOG INPUT ONLY
Sampling Size and Rate:24-bit, 48 kHz
Audio Frequency Response:20 - 20 kHz, +/- 1 dB
Digital Modulation:8PSK


D4T
Digital Hybrid Wireless Diversity Transmitter
2 or 4 channel operation
 line level analog audio signals and AES/EBU digital audio signals
48 kHz/24-bit audio, ruler-flat 20-20000 Hz frequency response

 

 

and now just announced in 2019
DCHT (Digital Camera Hop Transmitter)
The DCHT accepts two channels of mic or line level analog signals or an AES digital signal from a mixer and transmits to the receiver or receivers in a purely digital format.

Frequency Response: 20 Hz -10.5 kHz ± 1 dB
Compatibility Modes: • DCH (Digital Camera Hop)
Digital Modulation: 8PSK
Specifications subject to change without notice
On Gotham Sound website they list:
Frequency Response    20 Hz – 14.5 kHz ± 1dB

On the manual's DCHT Block Diagram is a "Rate Converter"

So that would mean the AES3 digital 24-bit/48kHz signal is getting SRC (Sample Rate Converter) to 32kHz inside the DCHT before transmission?

DCHT Ok for most dialogue but not music.

Opinions?

 

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48 minutes ago, PCMsoundie said:

So that would mean the AES3 digital 24-bit/48kHz signal is getting SRC (Sample Rate Converter) to 32kHz inside the DCHT before transmission?

 

Why do you think 32k? Is there a mention of that somewhere?

SRCs are often used on digital inputs when an external clock signal (like wordclock) is not available, or if not all digital devices used can be clocked. 

 

51 minutes ago, PCMsoundie said:

 

DCHT Ok for most dialogue but not music.

Opinions?

 

 

I have not yet heard the system myself, nor have I looked at any official material whatsoever. But purely based on the numbers you listed, why would this not be suitable for music?

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I've often referred to this chart when making decisions about filters for music recording purposes...

 

http://www.independentrecording.net/irn/resources/freqchart/main_display.htm

 

For purposes of IFB for film and television - not an issue.  For purposes of IEM for musicians, not an issue either.  If you are recording percussion instruments and planning on using this as a critical part of the signal chain, yes it will filter out harmonics and "air" - not part of the instrument sound itself, but some of the overtones that add to the sound in the end.

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Frequency response 20Hz - 10.5kHz +/- 1dB does not mean transmitted signal will top out at 10.5kHz. It just means that it will deviate by more than +/-1 1dB from the „ideal“ line. In practice this often means that the frequency range is often not that much higher, but not necessarily. Some manufacturers also publish frequency range figures in addition to frequency response...

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On 3/6/2019 at 10:11 PM, Constantin said:

Frequency response 20Hz - 10.5kHz +/- 1dB does not mean transmitted signal will top out at 10.5kHz. It just means that it will deviate by more than +/-1 1dB from the „ideal“ line. In practice this often means that the frequency range is often not that much higher, but not necessarily. Some manufacturers also publish frequency range figures in addition to frequency response...


I asked a local reseller and he told me the DCHT cuts off hard at 10.5
I also heard they raised that number by a firmware update?
Or is all of this incorrect?

Thanks

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Data sheet now lists -3 dB at 11.3 kHz. Probably exactly the same specs as before just 3 dB point instead of 1 dB point. The cutoff is not due to sample rate but bandwidth restrictions (occupancy) of two audio channels under FCC rules and EU rules. Bandwidth occupancy for 0 Hz to 10 kHz is the same as for one single octave of 10 kHz to 20 kHz. Tossing away that upper octave allows two channels of audio information. It's not what I'd pick for my hi-fi system but that's not its purpose anyway. Plus at my age, a 10k range is becoming overkill.

Best Regards,

Larry Fisher

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On 10/8/2019 at 7:17 PM, LarryF said:

Tossing away that upper octave allows two channels of audio information. 


Perhaps a good idea could a mono and full range system in the future then. 
OTOH a system topping out around 12k or whatever might actually be beneficial for an ifb system

 

 

6 hours ago, Ontariosound said:

Seems late to the party and under spec'd.


What do you mean by „seems late“? Either it is late or it isn’t. And late for what? Considering there aren’t many digital ifb systems on the market today, you could also say it’s right on time. 
 

Which specs would you like to be higher?

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On 10/12/2019 at 1:23 AM, Constantin said:


Perhaps a good idea could a mono and full range system in the future then. 
OTOH a system topping out around 12k or whatever might actually be beneficial for an ifb system

Seems like a good idea and should be relatively easy to do. I will pass it on.

Best Regards,

Larry Fisher

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Has any thought been put into completing the camera hop system with a receiver with a six pin plug to be a reverse of the transmitter for us so we  (sound people) don't have to worry about the cable now used with the IFB unit coming unplugged at the camera? I also see the on/off volume knob going away. The old receivers would become very high end IFB's for directors, producers and Red Cameras.

 

 

Scott

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14 minutes ago, carbonhobbit said:

Has any thought been put into completing the camera hop system with a receiver with a six pin plug to be a reverse of the transmitter for us so we  (sound people) don't have to worry about the cable now used with the IFB unit coming unplugged at the camera? I also see the on/off volume knob going away. The old receivers would become very high end IFB's for directors, producers and Red Cameras.

 

 

Scott

My thoughts exactly!  How hard would it be to include a threaded connector on the M2R, a simple solution...go figure!

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