Primus 360 Mod

[WmAx]

Do you know of any 3rd party measurements done on the Beta series? I know it doesn't always mean better quality but those are the next series up. A pair of 50's use to go for around $500 I think but I'm not sure if the CMMD drivers measure out as nice as the MMD ones do. The cherry Beta's sure look nicer.

Here's a review on the 360's with a link to measurements at the bottom of the page:

http://www.stereophile.com/floorloudspeakers/605infinity/

From what I can tell, CMMD is MMD. The difference is in the marketing, at least as far as I can tell.

-Chris

 

[Spkr_Bldr]

From what I can tell, CMMD is MMD. The difference is in the marketing, at least as far as I can tell.

-Chris

I thought the anodizing material they used was different. I remember reading a Harman white-paper saying that the CMMD anodization had a significantly higher young's modulus and better self damping than the MMD.

 

[WmAx]

I thought the anodizing material they used was different. I remember reading a Harman white-paper saying that the CMMD anodization had a significantly higher young's modulus and better self damping than the MMD.

I have measured drivers both marketed at MMD and CMMD. The diaphragms look very similar, and are both very very stiff feeling, and they both have similar properties, where the resonance is pushed very high, more so than with many metal diaphragm drivers. One of the key design points in the Primus line, btw, was to design stiff drivers that could be used without notch filters to trap the resonant peaks. The cones had to either push the resonances so high, or had to narrow the peak and dampen it sufficiently, that a simple 2nd order electrical filter could sufficiently deal with it. Could they be different from CMMD? Possibly. But if they are, it's a very small difference, I think. I think both are just super deep anodized aluminum(applying a 20/60/20 ratio anodize; 60 being the aluminum core), and this process seems to work really well. I would like to see SEAS Excel motors combined with the Infinity MMD/CMMD cones; that would make for something special.

-Chris

 

[Alex2507]

Now, with the 4" mid in that Primus 360, I do have measured data for that unit, and with the particular xover point is uses, and it's T&S parameters, it should not have much impact at all, if it is over damped or lightly damped, so far as it's over-all amplitude level is concerned.

-Chris

Speaking of that 4" driver, is there only one 4" driver in the Primus line? That's what's in the satelites and center for their HTIB? I read a post of yours talking about how much power they can handle over and above what they are rated for. Are these the same 4" drivers that you have the T/S parameters for?

Primus Theater Pack
Satellites Center Channel
Frequency Range: 100Hz – 20,000Hz (±3dB) 100Hz – 20,000Hz (±3dB)
Recommended
Amplifier Power Range: 15 – 100 watts 15 – 100 watts
Sensitivity: 86dB 87dB
(2.83V @ 1 meter)
Nominal Impedance: 8Ω 8Ω
Crossover Frequency: 3000Hz, 24dB/Octave 3000Hz, 24dB/Octave
Midrange Driver(s): 4" (100mm) MMD,™ Dual 4" (100mm) MMD,™
magnetically shielded magnetically shielded
High-Frequency Driver: 3/4" (19mm) MMD, 3/4" (19mm) MMD,
magnetically shielded magnetically shielded
Dimensions (H x W x D): 9-5/8" x 5-15/16" x 6-13/16" 5-5/16" x 14-1/4" x 6-13/16"
(245mm x 150mm x 173mm) (150mm x 363mm x 173mm)
Weight: 7 lb (3.2kg) 10 lb (4.5kg)

That didn't copy very well. It's suppose to be two seperate columns. One for the satelites and one for the center.

 

[Alex2507]

Primus PC350 Mod

The PC350 wanted love too.

These are the mids. See how there is a big gap at the magnetic shield on the driver on the right? The other side of it is tight like the driver on the left. The shield is on a little cockeyed.

I cut the lip off of the 5" woofers to be able to get to the eneven gap with a new pair of Craftsman tin snips. They are better for heavy cutting than other brands. Even though the snips are 'cuts-left', they are meant for your right hand. I'm using my left so that I can take the pic.

This shows the variation in the gap on the 5" woofers.

Where the gap was big I used this to fill it. This stuff is pretty sticky. Not too technical I hope. I didn't put any where the gap was small because I wanted Super Glue to be able to get to it.

Here's a pic of the caulk in place.

Vibration isolators were stuck to the back walls of each compartment by some double sided 4" wide roofing rubber. I stuffed Infinity's fill back in over top of some small pieces of duct liner that I had left over (sides only). The stock fill was glued to the top of the cabinet using that same roofing rubber. I just wanted to use up anything had that I thought might help reduce resonance while I was in there. No claims are being made to the effectiveness.

Finally a small squeeze was given to the back end of each connector to insure a snug fit.

That's all folks. (I had to take out the smilies. Too many images.)

 

[Buddy17]

not to bring up the old post, but i had to thank you for the pics! How did it turn out??

 

[Alex2507]

not to bring up the old post, but i had to thank you for the pics! How did it turn out??

I think it turned out pretty well.

I had a reason to go into my right speaker recently and added some damping material to the base of the cab. In the week or two that it took me to get to the left one I could hear an unpleasant characteristic in the left one. Once I got the same love put into the left side the characteristic was gone. So the benrfits are real but if you do them both at once they are not so easy to pick out.

I just listened to The Phantom of the Opera followed up by 3 Doors Down.
I liked it.

 

[Something_Soft]

Hey, the pictures don't work anymore, darn.

So you glued the drivers or something? What did that do?

Is it worth it to put better foam insulation in?

Not worth it to upgrade the crossovers?


One of my tweeters is popping. Dang. I need a replacement, correct?

Any help would be appreciated. Thanks!!!

-Andy

 

[Alex2507]

Hey, the pictures don't work anymore, darn.

So you glued the drivers or something? What did that do?

Is it worth it to put better foam insulation in?

Not worth it to upgrade the crossovers?


One of my tweeters is popping. Dang. I need a replacement, correct?

Any help would be appreciated. Thanks!!!

-Andy

I glued the tuna can looking magnetic shield to the speaker to eliminate a bit of a ringing rattle which can be revealed by knocking on the shield. Once you take one of those drivers out you will be able to see what is being refered to.

I imagine that acoustic foam would be better than what is already in there which amounts to nothing. The posts by WmAx recommend a rigid fiber glass made by Owens Corning or perhaps mineral wool. His posts are pretty clear and have been linked in this thread.

I haven't come across any recommendations for upgrading the crossovers.

A member named lsiberian may be good enough to post a link to where replacement parts can be found for Infinity speakers. Probably from their support page but he should be around. I'm not sure that that is your problem though.

 

[Something_Soft]

I glued the tuna can looking magnetic shield to the speaker to eliminate a bit of a ringing rattle which can be revealed by knocking on the shield. Once you take one of those drivers out you will be able to see what is being refered to.

I imagine that acoustic foam would be better than what is already in there which amounts to nothing. The posts by WmAx recommend a rigid fiber glass made by Owens Corning or perhaps mineral wool. His posts are pretty clear and have been linked in this thread.

I haven't come across any recommendations for upgrading the crossovers.

A member named lsiberian may be good enough to post a link to where replacement parts can be found for Infinity speakers. Probably from their support page but he should be around. I'm not sure that that is your problem though.

Very awesome thanks. God bless the internet. I never would have known you could try modding some of your speakers! Fun!

I heard replacing some of the capacitors that are in line with the tweeter could help. Replacing with Solen caps? He wasn't sure though, so I'm not sure.

Might be fun adding some fiberglass! Thanks!



Very awesome.

 

[Alex2507]

I heard replacing some of the capacitors that are in line with the tweeter could help. Replacing with Solen caps? He wasn't sure though, so I'm not sure.

I have seen these discussions. My take away message was that a replacing parts with other parts that have equal values would be a waste of time and money. Check out the link in post #14.

 

[Something_Soft]

I have seen these discussions. My take away message was that a replacing parts with other parts that have equal values would be a waste of time and money. Check out the link in post #14.

How the heck do you unscrew the drivers? The screws are strange looking and don't work with a Philips. Lol.

 

[Alex2507]

How the heck do you unscrew the drivers? The screws are strange looking and don't work with a Philips. Lol.

Torx 20 screws are used. It's mentioned in the first post but without the pic's ...
Be very careful not to jamb the screw driver through the cone.
Pay attention to your hands and the screw driver the whole time.
Don't start like letting your mind wander.

 

[Something_Soft]

Torx 20 screws are used. It's mentioned in the first post but without the pic's ...
Be very careful not to jamb the screw driver through the cone.
Pay attention to your hands and the screw driver the whole time.
Don't start like letting your mind wander.

lol. gotcha. thanks.

 

[STRONGBADF1]

Torx 20 screws are used. It's mentioned in the first post but without the pic's ...
Be very careful not to jamb the screw driver through the cone.
Pay attention to your hands and the screw driver the whole time.
Don't start like letting your mind wander.

Mind wonder...that would never happen to a monkey..........