Phase Switch

organ

After reading about this in several other forums, I decided to give it a try. Apparently, a lot of CD's out there were released 180o out of phase and that's why many units have a phase switch on them. I started playing around with the switch on my DTI and it made quite adifference on many recodings. The incorrect phase is more blurred and sometimes sound thinner. It seems like the sibilance stand out more when the phase is wrong. Finding the right setting also made some of my CD's sound much warmer. But te biggest difference is the soundstage.

If you own an equipment that can do reverse phase in the digital domain, give it a try. You'll be surprised by the results. Now I need to mark down cd's that sound better on reverse.

I hear you can also do this by switching the speaker wire polarity but a lot of the differece you'll hear in this set up will be from the caps in the x-over getting reverese polarity. Digital switching won't do this.

Maurice

rlw

From the Silent Running Audio WebSite:

Phase Chart

Tour2ma

Interesting posts... Thanks for the link, rlw.

I've gotta start playing and paying attention to this as well maurice. Will be curious to see if our observations match the list in the link.

gidrah

Thanks, I'll keep an ear out too. My integrated has this switch.

Question though. I was always under the impression that a phase shift of 180 degrees is only noticable when compared to something "in" phase. Meaning that if you changed both sides, you wouldn't notice. I can even tell a difference with single drivers though.

madmax

I read somewhere recently that phase changes of 180 were previously thought to not to sound any different. Tests they ran proved that this was only true with simple sine waves. Complex waveforms actually change the sound. I forget all the changes they listed. I will pass on the link if I can find it.

I've been switching phase with my Audio Alchemy DAC recently and sure enough one way always sounds better than the other. For me it varies depending on the disc. I wish my new Audionote DAC had the phase switch.

Also, my preamp reverses the phase because they left out a final stage which only reverses the phase back to normal. (for noise reasons). My delimma is do I change the phase from my Phono cartridge and let the CD remain reversed OR do I reverse all of the speaker phases (remember I have the SDA's so you can't just change the main + and -).

madmax

Tour2ma

Originally posted by madmax
...(remember I have the SDA's so you can't just change the main + and -). madmax

I must have slept through that class. When did that come out?

madmax

Originally posted by Tour2ma
I must have slept through that class. When did that come out?

If you swap the + and - on the main terminals the SDA cable will connect the + of one amp channel to the + of the other amp channel (used to be the two negatives when hooked up normally). BOOM! You have to change the + and - going to each individual driver instead. Maybe you could isolate with a transformer but I'm not sure the SDA would still work. It may or not, I'm not sure.

madmax

organ

Thanks Rlw, I'll make a printout of that.

Looks like Madmax can hear a difference too. Sometimes it can be quite drastic.

Tour,
Did you receive the Pro 32 yet?

Gidrah,
There's an explanation in this link.

http://www.soundstage.com/maxdb/maxdb101999.htm

and another

http://www.positive-feedback.com/pfbackissues/0706/cj.01.7n6.html

Maurice

Tour2ma

max,
All I can say is when I bi-amped last year, I had the tweeters channels reversed and wired out of phase to boot, but no boom. So I don't know... Scary thought though.

maurice,
Yup... received mine and yours... Also nailed a DTI Pro (no 32) and a DTI Plus for comparison sakes. Just about have all the DTI's now.

Still checking them out. Will update later.

madmax

Originally posted by Tour2ma
max,
All I can say is when I bi-amped last year, I had the tweeters channels reversed and wired out of phase to boot, but no boom. So I don't know... Scary thought though.

Oh well the tweeters are straight forward. Either way with no problem. Just FYI, when you start messing with the midbasses they are wired really freaky with the SDA thing. The two ground inputs on the L&R speakers get connected to each other through the SDA cable, thus the need for the isolation xformer. It gets worse than that because you have to consider how the SDA works to figure out what you can do with the inputs. A long study for me since 1989 and I still don't have all the answers... Never assume ANYTHING with the SDA midbasses or you will pay big time when it comes to replacing amplifiers.

HBombToo

I have heard minor changes from flipping the phase switch on my DTI. Perhaps its just the sources that I'm running. I will say this though... DON'T flip the phase if your passing a DD stream through the DTI! It don't worky soooooo goooood:(

HBomb