Forums Music Sound Engineering monitor source switching..

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  • #1052312
    General Lighting
    Moderator

      At some point (possibly nearer spring/summer though as I’m caught up with work at the moment) might do some radio shows for PV radio. I’ve done various legal and pirate stations in the past, so got all the kit set up (I tend to use a mixture of club/mixing setups and standard broadcast practices which I know works as I used it 10 years ago). What I’ve got currently is the Citronic MPX10 / Voxoa S60 as the decks or “grams”, using its onboard mixer for track mixing and headphone monitoring (in this mode both its DSPs feed analogue audio into the mixer section, which sounds slightly better than in MIDI control mode in spite of having a fairly powerful desktop to run Virtual DJ on).

      This feeds a Behringer mixer which would also play in any jingles, sounds from a microphone or any other sound sources. Got one thing to sort out though. Should I choose to use a microphone for announcements, of course I have to mute the monitor loudspeakers as otherwise I would either get a great din of feedback, even if I have the speakers playing a clean feed of the MPX10 audio mix that gets into the mic and screws up all the levels / compressor (thus defeating the purpose of running the mic through the mixer and not the MPX10)).

      Also the output of the cans off the MPX10 will only have the monitor channel from that local mixer, not the Behringer output (which I also want to monitor) At the moment I am actually feeding this and the behringer output into a further small soundcraft mixer and using that for the cans (using the two track to monitor button), which is overkill, plus when I do start broadcasting that soundcraft may well end up being used at the end of a long balanced line to distribute the program audio into a different computer downstairs (as I’ve no space for it upstairs).

      Most legal stations I worked on had a desk where the studio monitors could be switched between a variety of sources (usually desk feed, off air TX and remotes), also bringing up the mic fader would automatically mute the speakers to avoid the issues with feedback or stray audio. These desks are way expensive though and I don’t have the room for them anyway. Also the “off air” feed from a Internet radio station is delayed 10-20 seconds so not much use for real time mixing (whereas Band II (FM) is pretty much real time unless there is a deliberate delay on it (anti swearing etc for phone ins).

      I could of course build a switcher for the cans and maybe even to mute the loudspeakers the old skool way out of British Telecom type 47 reed relays or even key switches and other bits and pieces, but thats a fair bit of effort, and BT key switches are getting pricey these days as they aren’t made in great quantity and the old boys of my dads generation hoard them in their sheds and workshops for their own projects. The other issue with the extra mixer is limited space means it is often put near the MPX10 and I end up knocking the control wheels or worse, getting confused and putting off the wrong deck and all sorts.

      What I am looking for is a device with a decent sized set of buttons / keys which switches the cans between the behringer opt and the MPX10, and maybe also can drop levels on the loudspeakers. is there any sort of kit what does this you can buy off the shelf (and doesn’t cost loads such as kit out of Canford Audio (already looked there)?)

      #1248879
      barrettone
      Participant

        Sounds awesome. I wish I had money to buy equipment to have my own radio show. Where would you suggest acquiring such items?

        #1248868
        General Lighting
        Moderator

          compared with a few years ago the equipment is not that expensive TBH… if anything its dropped in price. probably worth looking around here as every so often folk sell off bits of equipment as they either upgrade or have other priorities in life. it tends to be speakers and rigs mostly but you do occasionally see smaller audio items sold off..

          #1248875
          cheeseweasel
          Participant

            Ok I’m fairly pissed as I’ve just got back from pub and so haven’t read the OP properly, but is this of any use??

            Mackie Big Knob

            Mackie – Big Knob

            I’ve come across these in various small studio setups and can’t really fault it. Will try make a more coherent post tomorrow at some point.

            (Btw all the buttons have disappeared from the reply box – link/video/pic/etc…)

            #1248869
            General Lighting
            Moderator

              Thats pretty much what I want although a bit on the pricey side TBH especially as I wouldn’t be using the talkback circuit (PV radio has realtime chat and isn’t timed to the second anyway like a band II station, and even if I did need realtime voice there’s an entire small digital telephone exchange in this house :wink:)

              That is a smart piece of kit but for that sort of money I probably would be looking at doing it similar to the old skool way,,,

              Type 47 relays are still cheap (BT still use them where I work out in the sticks in the Exchange) its ironic that using press buttons and a microcontroller to trigger them is now more affordable and quicker than getting hold of Post Office/BT key switches (which were used in many broadcast consoles for this sort of purpose) – Also something like an Arduino can even simultaneously send the MUTE code to the amp off a IR LED… but they stopped state making solid state audio switches in DIL packages years ago 😥 (I don’t do SMD stuff if I can help it, way too small).

              #1248876
              cheeseweasel
              Participant

                How about getting a Soundcraft Notepad mixer for £75?

                http://www.amazon.co.uk/dp/B00392T7YG/ref=asc_df_B00392T7YG6419218?smid=A3P5ROKL5A1OLE&tag=hydra0b-21&linkCode=asn&creative=22206&creativeASIN=B00392T7YG

                Then send main L-R to the Tx

                Create a mix-minus on the aux bus to send everything but the mic to the monitors

                Feed the monitor output from the decks into the 2-TR input.

                Plug the headphones into the mixer and you can then choose between 2-TR (deck monitor mix), Aux (same as the monitor speakers) and main L-R (send to Tx).

                Or is this pretty much the setup you have at the moment?

                Edit: just noticed the aux is pre-fade so might not be an ideal solution

                #1248870
                General Lighting
                Moderator

                  that is prety much what I’ve got at the moment. What I do is feed the cans opt of the MPX10 into 2-TR and the main mixer OPT into one of the stereo channels.

                  Which is fine until I hit the wrong grey button and send the circuit for the cans into the program feed 😥 Also as my music/computer area has grown a fair bit space is limited (there are two 1920 x 1280 monitors here, another laptop and a 1024 x 768 screen) and also a bulky laserjet 6 I need for work – so finding somewhere for the soundcraft where it won’t be knocked into when reaching for other equipment is a problem, and the soundcraft will probably go downstairs anyway where the “lines area” is (actually under my stairwell) to pick up the balanced audio feed (and be a final safeguard against putting in excessive level) where a further PC and soundcard sends this audio to the Internet as it will pick up the balanced line from the Behringer.

                  Dunno if you’ve ever heard of Neve but I’m on a mailing list with one of the top boffins from there (got specially invited there due to another interest in historical comms) and we were discussing the design of broadcast consoles and how they were made specifically so its hard to knock off live feeds by accident whilst giving as much versatility, and thus why the old Auntie and iLR ones are way bigger than much of todays kit.

                  Also if you look at Ferry Maat’s console in 1972 and the one he uses today in his computerised studio, he’s kept much the same design in those 40 years…

                  #1248877
                  cheeseweasel
                  Participant

                    Yeh I’ll admit it’s a less-than-ideal solution. Maybe building something yourself is the answer then (incidentally the Big Knob has roughly the same footprint as that Soundcraft so if space is really that tight it might be your only option).

                    Yeh I know AMS Neve, they’re based in Burnley, not far from where I grew up. We had a Neve V-Series in one of the studios when I was at uni. Built like a tank, great desk to work on once you’ve got your head around the in-line channel format common in large recording consoles. We also had a really old Neve broadcast desk of some sort in one of the edit suites – I remember for one piece of coursework we each had to figure out how it worked and draw a system diagram of it.

                    I also did some work experience for Calrec when I was about 15 which is what first got me interested in audio engineering (their factory is in Hebden Bridge, literally 1 minute’s walk from my parents’ house). Those are probably the best broadcast desks in the world – they’ve recently stopped making analogue desks entirely, which is a shame but understandable given that digital desks have so many advantages in the broadcasting world where time is at such a premium.

                    I also worked at Cadac in Luton for 6 months, who make probably the best live sound desks in the world (though they’re rarely seen outside of the theatre industry). I wasn’t doing anything particularly clever, mainly soldering circuit boards and bolting little bits of metal together for days on end. Incidentally they’re the only desks I know of where the signal remains balanced throughout the console (i.e. if you take a module out and look at the circuitry you’ll see two of every component, one for the +ve and -ve leg of the balanced circuit).

                    #1248871
                    General Lighting
                    Moderator

                      the advantage with digital is also that broadcast stations (especially modern ones) by their nature contain all manner of RF interference – much is from computers but even if the main TX is not in the same place there are things like talkback feeds to radio cars, handheld radio sets used by rentaguards, guests and presenters may arrive via taxicabs and these chuck out a fair bit of RF when transmitting. Also British Telecom and Arqiva now provide digital feeds to the TX sites these days anyway – not 100% sure how its done but its near realtime in comparison to net broadcasting otherwise the pips and other time signals would be way off.

                      Also you can’t get many of the components used in analogue desks, or they are very expensive especially transformers, as those who wound them in Europe are now getting old and their eyesight isn’t so good, and the only new decent ones are from places like Japan and Singapore and even then its old chaps making them, as younger folk there want to make computers….

                      probably will be a homebrew job, especially as then I can just put one big button next to the mic channel on the mixer which switches the relays, dims or drops any loudspeaker feeds and have the rest of the audio wiring elsewhere (there is space underneath the PC desks) (might even be able to switch them to the small “squawk box” at low level and avoid feedback) and even light various red LED’s as a warning the mic is live… might even be able to fit a lever microswitch above the mic channel which would have the added advantage of stopping the gain being ramped up way too high…

                      if I build it I will put the circuit up on here as its something many net broadcasters and those making podcasts or shows for community radio in a home studio (as opposed to the main ones) might have to deal with.

                      Whilst on many stations (especially those playing urban) what they often do is put the MC in a separate room and MC’s tend to chat very close to the mic, but often they are completely distorted and you can’t hear what they are saying anyway, or if they are DJ’ing as well end up putting the music level down so much (or using that “talkover” switch found on some mixers which is intended for cheesy mobile DJ’s) that it becomes intrusive.

                      #1248878
                      cheeseweasel
                      Participant

                        Yep, hadn’t really thought about that but seems a fair point. A large metal-framed console is basically a big antenna. At Cadac they took EMC very seriously, and we had a test chamber with a massive aerial in it that blasted the desks with RF to see how well they coped (and could also be used the other way to measure RFI radiated from the desk). Each desk had multiple earth bonding points all over it, and the whole thing was earthed with a huge cable about 1/2 an inch thick (my knowledge of RF engineering and EMC is pretty much non-existant but I was told all this was done for EMC reasons).

                        #1248874
                        Raj
                        Participant

                          GL I havent read this carefully but will come back and do so and add my 2ps worth :obey:

                          #1248872
                          General Lighting
                          Moderator

                            @cheeseweasel 466392 wrote:

                            Yep, hadn’t really thought about that but seems a fair point. A large metal-framed console is basically a big antenna. At Cadac they took EMC very seriously, and we had a test chamber with a massive aerial in it that blasted the desks with RF to see how well they coped (and could also be used the other way to measure RFI radiated from the desk). Each desk had multiple earth bonding points all over it, and the whole thing was earthed with a huge cable about 1/2 an inch thick (my knowledge of RF engineering and EMC is pretty much non-existant but I was told all this was done for EMC reasons).

                            they had similar kit where I used to work but it rarely got used as only the old boys knew how to work it (they actually bought the CE stickers in reels and bunged them on anything, sold it, and waited for the Germans or Danish to complain at us when stray signals or other flaky kit hosed some important broadcast) :crazy:

                            just found a load of free software PPM/level meters programmed by a boffin chap from Auntie – gonna put up a link to these as they are really good,although it seems that standard level that producers in NL use for trance tracks is higher than what Auntie use (though a ME12 PPM is a bit conservative by todays standards and digital dynamic range) or even Germany (where they leave 9db of headroom and warn everyone to keep out of it)

                            NL appear to take about 3db bite out of this, leaving 6db headroom, constant across tracks by AVB, Sander van Doorn, Ferry Corsten and Tiësto (bear in mind in NL these tracks are much more commonly broadcast on the radio than in the UK)

                            #1248867
                            Anonymous

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                              #1248873
                              General Lighting
                              Moderator

                                in the end I managed to get a 4PDT toggle switch and built the switch the old style (the case is actually the housing of a old electric fan. it is even weighted down with exhausted alkaline batteries so the thing does not get knocked over all the time..)

                                Having been trained by ex-BBC staff I still use the term GRAMS even these days with everything being digital (although seems I’m not the only one), though I can actually feed vinyl into the MPX10 if I so wish.

                                there is nothing clever here, it literally just switches the headphone feeds over between the Citronic and the Soundcraft monitor output (I’ve used the actual monitor / control room output on the Behringer to feed the speakers, so I can just turn it down as and when needed, decided that was less hassle than faffing around with making variable attenuator circuits for the moment.

                                Incidentally the program feed for diigtal broadcasting is now straight off the Behringers internal soundcard, provided I set the levels correctly and keep a watch on those PPMs it should not overload – the only reason I’ve kept the Soundcraft in circuit is to provide both a feed for the cans and a variable line level output for kit such as the Tascam audio recorder (which overloads on a standard line level signal off RCAs)

                                general-lighting-albums-alex-s-random-techie-stuff-picture81544-dscf0211-768x1024.jpg

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                              Forums Music Sound Engineering monitor source switching..