Open Baffle Phy HP KM 30 SAG update


Well, I finally got around to putting the PHY drivers in prototype baffles. I used 1/2" Birch plywood baffles that measure 45" X 27 3/4". I offset the drivers in the baffles.

When I first fired the speakers up I was disappointed, but I realized they needed to be broken in. My *heavily modified* Newform Research 645's were easily superior to what I was hearing from the Phy's.

I put a bass-heavy CD on repeat and began the burn-in process. The first 10 hours were depressing. The soundstage was flat, congested and had no air. There was a lower-midrange hump that was annoying. Even though the drivers were new, I was hoping for more.

Well, by the time the PHY's reached 30 hours, all of my fears vanished. I am stunned at how good these things sound. They have crushed my Newforms in every respect, as well as several other high-end speakers I have listened to recently.

The soundstage is now huge and 3D. The piano has the weight and size of a real grand piano and with phenomenal harmonics. I have never heard a better sounding piano on any speaker. The sheer weight and tonality of each note is striking. I thought the piano sounded good on my 645's (and I have a grand piano in my business that is played every night, so I know what it should sound like), but the PHY's are so realistic its scary.

Voices and instruments now have lots of air and there is a realism to these speakers that is hard to describe. The lower-midrange hump has vanished and speaker placement made a huge difference, as well. From the front of the baffle, they are 28" from the front wall and the center of the driver is 26" from the side wall. The drivers are 9 1/2 feet apart center-to-center and the imaging is outstanding. They simply disappear. The soundstage is huge and deep with an incredible mid-range and sweet high-end. It is hard to quantify how much more information I am hearing on the PHY's than my Newforms, but it is substantial.

I am sure the drivers will continue to break in and sound even better, but if they never improved beyond their current state, I would be incredibly satisfied. I was greatly concerned that the PHY's would have no bass to speak of in an open baffle - WRONG. They surely didn't at first, but now the bass doesn't sound much different on a lot of material than my Newforms. I suspect room gain is helping the PHY's. With the 645's, room gain was a problem, but with the PHY's I believe it is a plus.

The 645's clearly go lower, but the quality of the bass with the PHY's is also much better. Let me put it this way; I am going to explore dual subs, but if the bass improves just a little more with break in, I certainly won't feel compelled to add the subs. I don't listen to any rock, rap or organs, so the lowest octaves aren't that important to me. I plan on measuring them shortly to see just how low they are going and where they are rolling off.

I am going to proceed with making my permanent baffles using 1/2" Lexan for the front baffle and Koa for the smaller rear baffle that actually supports the driver. I think they will look great when completed and I am convinced they will sound even better than the simple plywood baffles.

I have a good friend to thank for the suggestion that I try the PHY OBs. I really trust his ears and he raved about another mutual friend's PHY OB's. After talking with the two of them (they both have $$$ high-end systems, go to CES every year and have heard it all), they convinced me that the PHY's were world-class drivers and were incredible in an OB. With a leap of faith I took the plunge.

Since the drivers only cost me about $2,800, I figured what the heck, I'd try 'em. If I didn't like 'em, I'd just sell them and take a bath if I had to.

Well, along with my Berning ZH270 (which I also purchased new without hearing it first), the PHY's are the best audio purchase I have ever made. I will post a follow-up after I finish my permanent baffles, but even with my prototypes, there's no going back to boxes for me. Now I know what the OB guys over at DIYaudio have been raving about.
fiddler
I am absolutely useless when it comes to woodworking etc. If I took the Battle Plan OB plan on the PHY-HP website to a cabinet maker are they definitive enough for him or her to produce said speaker design?
A customer of ours brought in a set of PHY KM 30 SAG 12" speakers, based on a series of reviews he read. One of the reviews recommended that our amps were a good match so he ordered a set of those as well.

I have to say the PHYs were quite impressive! At first we listened to a set of SET amps, and really, they did very well, although a bit odd (colored? humped?) in the bass. When we got our amps installed that and a lot more was transformed- it was easy to see why the reviewer (who was in Hong Kong) made his comments (although its hard to say how much was amplifier and how much was break-in- refer to earlier comments to see how important this is). A really nice easy load for any tube amp too. 16 ohms really contributes to improving transparency in tube amps as you reduce distortion that masks low level detail.
I really want to see som pictures of your open baffle "Fonz". I just got my hands on a pair of KM30 SAG drivers and gonna start building a open baffle or a box with open back...

I don´t have room for the recomended open baffle from PHY-HP website so I´m really interested in yours.

Do you still have them?

Cheers
Daniel
Silwerfeldt
I believe I have some pictures I can send you, the full and small scale.
Regards,
Fonz
Hello Fonz,

Based on your system, looks like you moved on from the PHY's?

I have a pair built into an OB, which I love. I was curious, however, how you went about making connections to the drivers. I'm currently using disconnect tabs to push onto the metal tags, yet was curious what you did. Did you solder wire directly to the metal tags? For such over-built, beautiful drivers, it seems beyond bizarre to have such a critical juncture serviced by what appears to be a 10 cent piece of tin, but I trust they know what they were doing.

Any help you can provide is appreciated (and I'd love to see the photos you mentioned if you have them handy). Thank you in advance for your time.

All best, Andrew