Speaker Selector Switchbox changes audio quality?

[kags]

So here's a question that might require it's own thread...

I realize this forum includes folks with MANY levels of requirements for monitor selection switching.

Question: How many sets of monitors are in YOUR studio setup?

I will "spit out" a LARGE setup I once designed/used:

1. Large soffit: UREI 813 pair
2. Nearfields on pedestals in front of the desk, models varied over time; last pair was a (forgotten model) of Tannoys
3. HorrorTones sitting atop the meterbridge.
4. The cheapest small 4" speaker from Radio Shack, driven from a mono sum into a 1 Watt amp and that speaker was installed in the desk's meterbridge. We called it the "Sh!tcan" <g>.
5. Set of large speakers in the rear wall of the control room. Reason? Main writer/composer played keyboards and his rig was behind the desk, facing the engineer and was below the soffit.
6. We experimented with a low powered FM transmitter to transmit to the parking lot for listening in our various automobile systems.

My setup had a selector at the desk that was "interlocked but not locked out" for the various choices. Usually only 1 choice was selected, but when tracking the engineer had the soffits or nearfields on while the speakers in the rear were also on for the keyboardist who was WAY off-axis for speakers at the front of the room.

Crazy, likely unique, requirements....probably not typical in year 2024. Hence my general question: How many speaker choices do YOU use these days....that require a selector?

Bri

This is probably not for everybody, but I have a large monitor-switching setup. I use software control (Ginger Audio Sphere). The software routes any audio source on my computer (DAW, iTunes, browsers, ZOOM, etc) and routes to my primary audio interface (Avid HDI/O). The software lets me switch between my Atmos 7.1.4 system, stereo mains, stereo cubes, heaphones, Apple Spatial output (via Mac's Bluetooth transmitter)) and more. There are 7 speaker outputs (up to 9.1.6 wide) available plus 4 more "AUX" outputs for downmixes/re-renders. These outputs all route to hardware outputs on my interface, so I'm using like 20 analog outputs from my interface.

Software monitor control makes me nervous, but I control this all with an Elgato Streamdeck USB controller that provides 8 pushbuttons plus 4 rotary encoders (with several layers of each available). It's been an amazing setup and saved me about $20k for a comparable hardware monitor controller and audio interface. Plus the Sphere software provides bass management options for each output plus one AU plugin slot per output for for monitor EQ or whatnot (I use SoundID Ref on some outputs). Oh yeah, the software also provides talkback, listenback, mono/phase flip, calibrated volume settings, LUFS meters, and probably more things that I can't remember. The same company makes a simpler software controller if you only need stereo monitor control, instead of immersive.

 

[kags]

Maybe also a tangent, but could have possible applications here. I used to have a custom guitar head/cab matrix switcher that would choose between three heads and three cabinets. The cabinets stayed loaded with 8 Ohm when switched out and all the connections were Jensen transformer isolated. Relays did all the switching. The box was built by LA Sound Design in Burbank, Ca. It was custom and expensive, but it was the right solution at the right time. I don't have it anymore, but I've found these boxes that seem similar:

https://www.khe-audioelectronics.com/
They are in Switzerland, but an email to them might provide some info on the relays they use for the high-level switching. Here are some specs from their website:

Switching Element: Relays, analog, sequential switched
Control System: Microcontroller, digital
Power Handling: switches max. 150 Watts per Channel
Amplifier & Speaker Impedance: 1:1 pass-thru, passive
Amp Switching: switches both guitar input and speaker output
Attenuator Insert: serial, passive, Speaker Level
MIDI Control: MIDI Input, 15 Channels, CC & PC Messages​

Switching Time: 15ms max.
Contact Resistance: > 0.1 Ohm
Guitar Input Impedance: 2,2 MOhm
Guitar Input Type: active buffered
Guitar Input Level: 15Vpp / +18dBu
Frequency Range: 10-100kz +/-0.2dB​

Dimensions: 234 x 174 x 44mm / 19” 1U
Enclosure: 1,5mm Steel
Weight: 3.5kg
Power Supply: 15VDC, 90-240VAC, external type, included​

 

[RoadrunnerOZ]

I built a dual switch box for a guy who had more pedals than you could imagine - he wanted 2 chains of FX pedals and have them in 2 rows in a pedal case with a switch between the two. I made a box with a single 4 pole stomp switch using an aluminium project box which I polish sanded and clear-coated. Then he wanted to be able to identify which row was on A or B - enter 2 DP relays, power socket (it got power from the pedal supply) same switch and 2 LED’s. So it was an A-A’-B-B’ box which sounded a bit like Saab so I printed a label with ABBA on it for a joke and stuck it to the box. After that a lot of guitarists wanted me to make them ABBA boxes.

 

[vintageampfixer]

Once you get away from the pure loudspeaker 'driver' itself and add any form of crossover, the quoted nominal DC resistance will bear little or no relation to a 'speaker's impedance at most audible frequencies.

Hi-Fi 'speaker circuits, despite voltages well below 20 or 30v RMS (and usually very, very significantly less in "real" listening) do present quite low impedance loads. At some frequencies, these impedances can be *astonishingly* low which obviously translates into very high currents, despite the small voltages.

We all should know that high currents flow best in short runs of large cross-sectional area conductors. Look at the starter motor cable on your car.

My guess here is that the switch box has internal wiring which is substantially smaller in gauge than the external wiring to the 'speakers, and that there's some resistance / impedance inherent in the switches; these things are almost always built down to the lowest price, so thin wire, poor solder joints, smaller switch contacts, weaker springs in the switches, etc., all of which culminates in 'resistors' (with a pinch of inductance too) effectively being added into your 'speaker circuit.

This creates two noticeable effects: one being limper bass response and duller HF, another being a change in the effective damping factor - which is how well the amplifier is able to control driver excursion without the output stage, speaker circuit and drivers becoming a resonator. It’s hard to describe the effect of this in words but the best I can come up with is slightly lacking in definition, or not crisp.

It's easy to be dismissive. But from experience (ahem, let's say 40+ years), I'm very confident in stating that short cable runs, properly tightened screw terminals rather than banana plugs, no switch boxes, and really heavy speaker cable all make massive differences to the sound you reproduce.

Inside the amplifier itself, there's usually as much improvement to be had from careful power supply design as there is from whatever faddy amplifier circuit is in vogue this month! 'Nested Differential Feedback Loop' designs might be seen as one example ...

Now I'll just qualify that I'm discussing what I view as 'proper' amplifiers, Class A or A-B. Class D is alluringly cheap, massively efficient and sound remarkable … usually by dint of some kind of ‘tuning’ process which allows the system to digitally compensate for weedy loudspeaker drivers, cheap cables, etc. I have several Sonos room sets – they’re great … but Hi-Fi they are not.