Solving Wiring Issues When Upgrading To A New AV Receiver
This story is about a situation that is becoming more and more common. A customer of ours had replaced an older AV receiver with a new model. I do not know the make/model of the old receiver, but the new one is a Sony STR-DN850. The complaint was that the in-wall sub-woofer no longer worked with the new receiver. The salesperson at the big box retailer suggested that the new receiver would work just like the old one. It didn’t. As you may have guessed, the salesperson was nowhere to be found after our customer made the switch. With no help from the big box retailer and the new receiver not performing as advertised, we got a call to begin solving wiring issues between the old sub-woofer and the new AV receiver.
Distributed Audio wiring
The speakers in the homeowner’s family room are nice, older, in-wall, Sonance speakers. The “sub-woofer” is a Sonance PSW1. A quick search online revealed that the model # PSW1 could not be found. No mention is made of this model number, either on Sonance’s website nor anywhere else online. I called Sonance and discovered that the sub-woofer pre-dated Sonance’s website. As the model wasn’t available when the website was created, it wasn’t included.
I also learned that the PSW1 shouldn’t be thought of as an in-wall sub. The speaker is a passive, dual cone design that does not have its own power supply. The way this speaker was designed, the front Right and Left speaker wires should go from the AV Receiver to the “in” side of the PSW1 speaker. The wires should then go from the “out” terminals of the PSW1 to the front Right and Left speakers. This effectively makes the large cone in the single PSW1 speaker part of both front Right and Left speakers. Unfortunately, this was not how the house was wired. The PSW1 speaker only had speaker wire going to it from the AV receiver. There were no output speaker wires from the PSW1 to the Right or Left in-wall speakers installed in the house.
Once I put all of the pieces of the puzzle together, I came up with two possible solutions.
To understand why the homeowner wasn’t getting the bass response he wanted, we need to know a little history. When the Sonance speaker system was installed in the house, state-of-the-art audio signals being sent to an AV receiver were analog. That meant that there were only right and left channel (or stereo) sound signals going in. Old AV receivers interpreted those signals and sent varying strength outputs to the front Right and Left and rear Right and Left speakers to simulate surround sound. The difference in volume between the front and rear speakers was simply based on the programming built in to the receiver, or how the receiver was trimmed out.
New AV receivers have HDMI inputs which deliver digital sound signals that the programming decodes to send specific sound signals to specific speakers – including a subwoofer. This is where the 5.1 or 7.1 notation on AV receivers originates. 5.1 is short hand for five speaker channels (center, right-front, left-front, right-rear, left-rear) and one subwoofer. 7.1 simply adds a pair of side surround speakers to the list. 7.2 denotes the ability to run seven speaker channels and two sub-woofers.
When the homeowner upgraded to the new receiver, he also switched to using HDMI inputs from his cable box, Blu-Ray player, Apple TV and other sources. This meant that the receiver was getting digital sound signals. The new receiver decoded the sound signals being sent to it and tried to send sound signals to the proper channels. The trouble was that there was no sub-woofer connected to the sub-woofer out terminal of the AV receiver.
Once I put all of the pieces of the puzzle together, I came up with two possible solutions. I could add an amplifier to the homeowner’s system that would drive only the PSW1. The amp would need to accept the single-line signal in from the AV receiver, amplify it and send it to the PSW1. While this was the best solution, it also had the cost of a new amplifier associated with it.
The second solution was the one the homeowner chose. I simply added the speaker wires going to the PSW1 to the front Right and Left speaker outputs from the AV receiver. I then changed the setting for the front speakers on the receiver to “large.” Finally I re-programmed the receiver to only send sound out to five speakers and to not use the sub-woofer channel. The last step was the key. By telling the AV receiver that there was no sub, the programming did not direct the low bass notes to the sub-woofer out terminal of the receiver. Instead, the low bass notes were sent to the front Right and Left channels. The homeowner got his rumble back!
When integrating new equipment into an older system, it is a good idea to understand how the old system works before changing anything. Sometimes the new equipment just plugs in and works. Other times it doesn’t. If you experience the latter, don’t be afraid to ask for help. It’s better to pay a little bit to have a pro tweak your system and make it work than to pay a lot to replace the entire system at once.
About Brian Hill
Brian Hill is a home theater enthusiast who has an extensive background in sales. His interests include music & movies, F1 & NASCAR auto racing, hot rods (he has a '56 Nomad) and hockey — Go Sharks!
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