{"id":863,"date":"2018-04-20T14:45:36","date_gmt":"2018-04-20T21:45:36","guid":{"rendered":"http:\/\/silentsky.net\/wordpress\/?p=863"},"modified":"2019-09-30T16:51:39","modified_gmt":"2019-09-30T23:51:39","slug":"balanced-line-level-stereo-to-mono-summing-box","status":"publish","type":"post","link":"http:\/\/silentsky.net\/wordpress\/archives\/863","title":{"rendered":"Balanced Line-Level Stereo to Mono Summing Box"},"content":{"rendered":"

\"20180416_220635\"<\/p>\n

One of my most popular blog posts has been The Stereo to Mono Summing Cable that No One Makes<\/a>. I get contacted pretty much on a weekly basis from someone who wants to buy or build that cable to connect their iPod, phone, laptop, etc. to their PA system. I decided to take the concept a step further and build a balanced, line-level stereo to mono summing box. Just like the mono-summing cable, it appears that there aren’t any readily-available, off-the-shelf products that do exactly what this box does. There are some mic combiners (e.g., Galaxy Audio’s JIB\/C) that are made for connecting two microphones to a single input, but those use much lower-value resistors, making them unsuitable for line-level signals (I even contacted Galaxy about the JIB\/C, and that’s what they told me).<\/p>\n

\"20180416_220619\"<\/p>\n

Here are a few examples where such a mono-summing box would come in handy:
\n\u2022 You only have one channel input available on your mixer and need to connect a balanced, line-level stereo source to it.
\n\u2022 You need to sum the left and right stereo outputs of a mixer to connect to a single amplifier input for a mono PA system.
\n\u2022 You need to sum a stereo signal to mono for connecting it to one or more subwoofers (low frequencies are omnidirectional, so it’s generally desirable to send a summed mono signal to your subwoofer\/s).
\n\u2022 You need to connect the stereo outputs of a studio monitor volume controller to a single active monitor (“grot box”) such as an Auratone, Avantone Mix Cube, Behritone, etc., to test your mix for mono compatibility. This is the primary way in which I intend to use the box in my own recording studio.<\/p>\n

This build is slightly more complicated than the regular mono-summing cable. First off, it’s for balanced connections, so you have to solder a resistor (470 Ohm, 1%) into the path of each signal conductor (left +, left -, right +, right -), and there’s also a shunt resistor (20k Ohm 1%) that gets installed across pins 2 and 3 at the output connector. It also requires more parts (two female and one male panel-mount XLR jacks and a box to mount them in), making it slightly more expensive to build. But it’s still a fairly simple project. <\/p>\n

\"20180416_213412\"<\/a><\/p>\n

More recently, I’ve started building these into an XLR y-cable format with the resistors inside the connectors. The internal wiring is the same, but this reduces the cost significantly, since the steel box and the panel-mount XLR’s made up the largest part of the expense of the box format. This also require less cabling, since you can plug the y-cable straight into the balanced outputs of your first device and connect a single XLR cable to the male plug of the y-cable for connection to the input of the next device. <\/p>\n

\"y-cable<\/a><\/p>\n

\"xlr<\/a><\/p>\n

Links:<\/strong>
\n\u2022 Micmodkits.com<\/a> – my website where you can order a cable like the one described here.
\n\u2022 My original article about stereo to mono summing<\/a>.
\n\u2022 My Ebay listings<\/a>, where I keep cables and other items of interest up for sale.
\n\u2022 Contact me<\/a>, if you have questions or need other help.
\n\u2022 Why Not Wye?<\/a>
\n\u2022 The Magic Cable<\/a><\/p>\n\n


\n<\/a>
\n<\/center><\/p>\n","protected":false},"excerpt":{"rendered":"

One of my most popular blog posts has been The Stereo to Mono Summing Cable that No One Makes. I get contacted pretty much on a weekly basis from someone who wants to buy or build that cable to connect their iPod, phone, laptop, etc. to their PA system. I decided to take the concept […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[5,277,4,6,26],"tags":[195,197,196,193,198,192,194,199],"_links":{"self":[{"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/posts\/863"}],"collection":[{"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/comments?post=863"}],"version-history":[{"count":11,"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/posts\/863\/revisions"}],"predecessor-version":[{"id":972,"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/posts\/863\/revisions\/972"}],"wp:attachment":[{"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/media?parent=863"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/categories?post=863"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/silentsky.net\/wordpress\/wp-json\/wp\/v2\/tags?post=863"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}