- Written by Steve Smallcombe
- Published on 25 January 2008
Rear Panel Inputs and Outputs
The rear panel of the CVS4 has four inputs, one output, switching of six analog as well as digital (optical and coaxial) signals, plus an RS-232 port and an IR control jack. Of course, the area of interest to me for incorporating multiple high definition DVD players into my system is the six analog connections for each input. While these inputs are colored and labeled for convenience as a component video switcher, the manual makes it clear that all six channels are of equivalent bandwidth and functionality, and may be interchanged as desired; or as they also suggest, used to switch 5.1 analog audio signals. The CVS4 passively switches analog signals using high quality relays with gold clad, silver-palladium contacts, and therefore offer in a switch, the equivalent of physically swapping cables. I had looked at other component video switchers, but they were typically based on active circuits, and although they also would switch six analog signals, I was not convinced an active circuit designed for video signals would pass audio signals very accurately. Quite the contrary. Relays are a much better approach, especially if they employ break-before-make switching logic, as is the case with the Zektor. Relays really don't care what the signal is, or which way it is going, as long as it is within the bandwidth of the relay, in this case 200 MHz (-3dB), which is certainly good enough for audio!
The CVS4 can also be used in reverse as a one input, four output switcher if desired. Zektor claims the 200 MHz bandwidth (-3 dB, 70 MHz, -1dB) will handle all existing HD video signals if you want to use this unit for component video switcher. In that case, also of interest will also be the digital audio switching capability of the CVS4, which switches one output between four optical or four coaxial inputs. In keeping with Zektor's quest for flexibility, coaxial inputs are converted to optical outputs and visa versa, so one could have mixture of optical and coaxial inputs to the unit, but a single connection of either type to the receiver or SSP.While I have not used the RS-232 port or the IR input on the CVS4, both deserve a bit of explanation. (The HDS4.1 has neither the RS-232or IR ports.) Zektor calls their serial protocol KISS, or Keep it Simple Serial. I won't go into detail, but reading the specifications certainly suggest the engineers at Zektor have a lot of experience in this area and have tried to keep their protocol as simple and reliable as possible. Likewise, the IR control port will recognize the same IR codes as the front panel IR sensor with a signal voltage range of 3 to 12V in either unmodulated or modulated formats, with a modulation frequency ranging from 25 kHz to 250 kHz.
Installation and Use
As mentioned above, I was (and am) pretty happy with my current setup that includes an Anthem Statement D1 SSP. Since my DVD players output 1080p over HDMI, and since I have an external HDMI switch, I haven't felt compelled to buy or upgrade to an SSP with HDMI switching and video processing. Although I was not ready to upgrade SSPs, I did want access to the higher definition audio codecs on both Blu-ray and HD DVD players, and I wanted to do this with minimal expense if possible. Moving the six analog cables between my two DVD players worked, but certainly was not convenient, to say the least. When I found the Zektor HDS4.1 on line for $279, this seemed like a real solution my dilemma. For the reasons also mentioned above, I ended up with the somewhat higher cost CVS4 and I am extremely pleased how simple it was to install and easy to setup and use.
Since I am not currently using the IR or RS-232 ports on the CVS4, I have no doubt that the lower cost HDS4.1 with its plastic case, but otherwise identical switching specifications, would also have served me just as well. In practice, the CSV4 installed easily, but one does need to be careful to make sure that the inputs and outputs for each channel get from here to there without being reversed, i.e., inadvertently reversing the left and right surround channels. Perhaps this is obvious, but it does require some care given the number of cables and connections, but fortunately only needs to be done once, not every time you want to watch a DVD of a different format.I have now watched and listened to a number of high definition DVDs in both formats, and again there is not question in my mind that these codecs that use a higher bit rate and or uncompressed PCM for the audio do sound better. It is actually pretty easy to switch audio formats, essentially languages, in the middle of the DVD and repeat the same scene. This setup also give me a way to play my collection of DVD Audio discs, as that format is supported by my high definition DVD player.
There is one codicil about this approach however that I should mention; switching multiple sets of six analog cables involves LOTS of analog cables, eighteen to switch two DVD players and to connect to the SSP. I looked in my storage boxes before I bought the CSV4 and was surprised I had that many good cables sitting around, but then again, I used to have audio RCA cables connecting preamps to amps (now XLR), and at one point had two connected processors and cables to enable DVD audio via exactly the same 5.1 inputs and outputs used here. As I already owned eighteen analog audio cables of reasonable quality, the Zektor seemed to be the lowest cost approach that would accomplish my goals.
If you have to buy that many audio cables of reasonable quality, then that could easily change the economic equation, and upgrading receivers might be a better deal. At least you have options. Another point to consider before deciding on this 5.1 analog input approach is determining what sound processing options your SSP or receiver allows with the 5.1 analog channel input. Ideally, you will want to have access to all the bass management, THX processing, EX or 7.1 processing, music processing modes, etc., that one might use for watching a movie or listening to music using Dolby Digital via a digital input.
For instance, when I tried to select EX processing fo rone of the High Definition DVDs whose jacket suggested that the rear channel information was so encoded, I was disappointed to find that the software in my D1 did not support this mode of playback with the 5.1 analog inputs, only the digital inputs.This was only a temporary setback however, as I then downloaded upgrade my D1 to the latest software, and this allowed any processing modes available for the digital inputs to be used with the 5.1 analog inputs, thus allowing movies that were EX or 7.1-encoded to be properly played back using the 5.1 analog inputs.
It should also be noted that some DVD players, e.g., my Panasonic BMP-BD10AK Blu-ray player, have eight (7.1) analog outputs, not six. One might also remember that the Zektor HD7.1 supports 7.1 switching using eight analog channels. Since my SSP only has six analog inputs, I didn't really worry about switching eight analog channels, but if your SSP does support eight analog inputs, you might want to consider the Zektor HD7.1.In terms of setup, if your two DVD players have vastly different volume level or lip sync requirements, you may need to adjust these things for each player individually. Otherwise, I suggest that you leave all the speaker setting in the DVD setup menu at Large and the distances set to be the same, and adjust the room/speaker/subwoofer related parameters in the SSP setup for the 5.1 analog input. You will also need to tell your DVD player(s), via their system setup menus, to decode the various audio codecs and to output them via the analog outputs, not the HDMI output.
The Zektor CVS4 and the lower cost HDS4.1 are very versatile four input/one output switchers for analog and digital signals (optical and coaxial). Each input supports switching of six analog signals, and these six signals could either be component video, composite video and stereo signals, or six analog audio signals (5.1) in support of higher definition audio codecs now available on high definition DVDs. Since analog signal switching in the Zektor is based on high quality relays, not active circuits, it really does not matter what sort of audio or video signals are being switched. The Zektor products are also amazingly programmable in their approach to control LED lighting levels and other things.
If you have two high definition DVD players for which you want to access the higher definition audio codecs, and your SSP or receiver does not support these audio modes via HDMI, the Zektor CVS4 or the HDS4.1 are a highly recommended low cost solution to what I suspect is currently a pretty common problem. You will have to analyze your own system in terms of how well your SSP or receiver is meeting your current needs, and the proper timing of your next upgrade in this area. If, however, you want to buy a bit more time for your current equipment, and meet the requirements stated above, then the Zektor 5.1 analog switching approach should work for you as well. I am currently very happy with using the Zektor CVS4 to switch 5.1 analog audio between two high definition DVD players in my system.