Originally Posted by SCutchins
I have a Sony STR-DE685 receiver, my two mains are Infinity Primus 360 towers. I am replacing the towers with Infinity Beta 20 bookshelfs due to size issues (TV upgrade caused me to run out of room.)
Do you have a subwoofer? If you used the available resources including bass management properly, there isn't that much difference between Primus 360s and Beta 20s in actual use.
Can I add two more front speakers along with the Beta 20s and wire them either in series or parallel?
If you put them in series then you will waste the power capabilities of your AVR. Series operation = 16 ohm load which decreases the current flow to the speakers and causes a net loss of dynamic range for your system.
If you put them in parallel, then parallel operation will probably drop the load on the AVR well to below 4 ohms, and that has the effect of also decreasing maximum output.
If you run two speaker systems like this there is also a issue related to acoustical interference. The phase of their acoustical output will vary over the audible range and may cancel at some frequencies, causing rougher frequency response and bands of missing music.
The Beta 20s have a higher power rating than your AVR and are unlikely to be overloaded by carrying the load all by themselves.
If you lack the room for the Primus 360s, how is it that you have space for both the Beta 20s and Yamahas?
I'm wondering why you didn't choose the brandmate Infinity Primus 163 speakers - they have an excellent reputation.
I have some nice, very small 3-way Yamaha bookshelf speakers, dual 4" and a tweeter, and between them and the Beta's I think I could get some good sound.
Looks like you have a solution looking for a problem. If its not broke, don't fix it. use the smaller speakers to set up an office or kitchen system, or something like that.