Sorry George. More dust

ben62670

Metal domes scare me.
A few of the design problems with the 6 mid design is that we reach 116db peaks. To have a 90db tweeter that can keep up it would need to handle 250wrms to hit 114db. Now if you can use a tweeter that is 93db you can hit 117db with the same wattage. Another huge thing to over come is these things can not be toed in. We are at nearly 40 degrees of offset at the seating position. If you move left or right this is increased even more. I know that I can't hear much above 12k, but I want it right. I may have to raise the XO point to around 2.4k. The lobing, and phasing should be minimal at near field listening position like in a house. Right now it is at 3.3k, and there is some beaming from the mids. I am being over critical of this. The transition is pretty smooth, but with my 5.5's the transition is smoother.
BTW he has been listening to his Sonicap modded LSI's for 2 days prior to coming over, and he says ?(with a big grin)these smoke them in SQ;)

Systems

ben62670 wrote: »

Metal domes scare me.

No need to feareth this Metal dome,its sweet and detailed sounding without any hint of edge one might expect from a metal dome. Check Zaph's tweeter mishmash for his comments on it and the 1189.

A few of the design problems with the 6 mid design is that we reach 116db peaks. To have a 90db tweeter that can keep up it would need to handle 250wrms to hit 114db.

Who listens at those kind of levels?:eek: oh yeah you do.:DDon't forget that most of the musical signal will be below the tweeters operating range so the percentage of power distributed to the tweet will substantially less than to the midbass's.

The lobing, and phasing should be minimal at near field listening position like in a house.

Because you have your tweeter mounted beside and not above your mids, any lobing will be from right to left instead of up and down.You may get lucky if the mids and tweet are in phase, the lobe will angle inward towards the listening position.Aswell the lower the xover the less lobing becomes a problem.

ben62670

I have actually been listening at much lower level, but every once in a while it is fun to crank something:) I did a lot of reading last night, and the new Morel ET338 replaces the MDT33. I have heard lots of good things about them, and the off axis performance is very good. Another thing pushing me to them is I can get them for $220 a pair new;) From what I have read is you need to get into tweeters that cost around $300 each to go a step up from the Morel's. Also I have read that the Morel Supremes don't sound as nice as the MDT-33 or ET-338. The dome/VC assembly only cost about $20 if they get blown:)

Systems

Ooops my bad for suggesting the el cheapo SEAS tweets.:oI didnt Know your budget was >$200.Morel makes great tweeters to be sure,even though their MDT33's were Dynaudio D28 knockoff's;).

ben62670

GV#27 wrote: »

....MDT33's were Dynaudio D28 knockoff's;).

I read that. My budget isn't that high, but Jerry wants these done right. Normally the ET-338(MDT33) tweeters are $330. The big plus is the replacement domes. I will order spares ahead of time. I messed up with the MDT20's. I have a stack of blown ones and you can't get the domes anymore:( I had some SEAS domes that I liked, but they didn't handle low XO points, and the particular ones I had were know for having issues with the VC wire breaking from the terminals to the VC.

Systems

ben62670 wrote: »

I read that.

Back in the late 80's when I started into the speaker building thing,the Dynaudio D28's where the Queen Mom's of dome tweeters.Morel decided to get in on the action and made some very nice clones.Its too bad Dynaudio decided about 10yrs ago to no longer sell their drivers for DIY use.:(

I had some SEAS domes that I liked, but they didn't handle low XO points, and the particular ones I had were know for having issues with the VC wire breaking from the terminals to the VC.

Must have been an older one with a high Fs ( 1.5kish) ,most of the newer SEAS units have very low Fs's in the 5-600hz range so crossing over low is not a problem.

ben62670

I think the FS was around 1k, and I tried to make them keep up with 16 MW's per speaker. That and known issues with that particular model life was short. They did sound nice in my monitors.
Ben

ben62670

Well I am having mucho fun tonight. I changed a couple OpAmps in my DAC which changed the sound of the speakers. They were a little bass shy to me(not Jerry), and the upper mids had a bite to them. A properly designed passive XO compensates for these short coming to an extent. We are going active on this project. This is good and bad. Good no components in the signal path to change the signal, bad no components in the signal path to change the signal. Most recordings are engineered for the average user:( Well I dug through my parts. All I had was one OPA134 OpAmp I knew I don't just order just what I need. I dug around a bit and found a pair of them in a lost stash of parts. Well now the bass is slamming, and the rise/sustain/decay of instruments is spot on. These speakers are slightly less efficient than Polk SDA's, but scenically better IMO. These are fully BiAmped and on the lows I figure they are receiving 350wrs. The amps are at max (GFA-565's) and putting out peaks of 115db C weighted slow at the listening position clean. We are going to install the Morel ET-338 tweeters for better SQ and power handling. We are running these at 3300hz for an XO point which is way to high, and we just ordered new XO's crossed at 2200hz. This will help with the transition from the lows to the highs a lot. The SDA effect is the best it has been yet. One of the biggest lessons I have learned yet is synergy. It is a ****. We are near as good as it gets. I can't wait to demo these at the next gathering. Jerry is going to order the veneer, and the new tweets by then. All I have to say is wait for what others have to say.
Thanks
Ben

hearingimpared

Good **** Ben.

Systems

ben62670 wrote: »

... no components in the signal path to change the signal

They are there ,just a different type and in a different location.:D

Interesting results with the OPA 134 vs the 5534,next step is to try biasing them into class A.

ben62670

Well if I knew more:o I am trying to learn...

Systems

There are better ways but the simplest method is by adding a resistor between the output (pin6) and the neg voltage (pin4).Something like 10k would be a good starting point, lower resistances will bias it heavier into Class A but heat may become an issue.Monitor the chips body to be sure it is not getting excessively hot.

ben62670

Thanks Bro. Like I have said many times. I know enough to be dangerous;)

ben62670

Well the Mahogany veneer should be here Wednesday. We are going to get work Thursday. Thanks F1nut for the suggestions. A 4x10 sheet will do a set minus the backs. Those are going to be black.

ben62670

Well a good friend said if you want them to look like Mahogany...
Jerry and I bought 5 4x10 sheets of Mahogany veneer. For what we paid we almost stole them;) I wish my camera took better pictures. The cabs only have 2 coats on them, and no stain. They look much richer, and have no flashing. They are very uniform in color:)

jerryj12

Wow I'm famous, my picture is on the forum. No autographs please.

george daniel

looks like you guys are working you A$$'s off,, nice work gents.:)

jerryj12

Thanks George,looking forward to seeing you this weekend.

george daniel

I'm planning on showing up, but most likely it'll be late,as we are moving my mother into an assisted living facility,, but if you can,stick around,I might be bringing a pair of tubers.

hearingimpared

Nice work you guys, they are beautiful.

Face

Nice job, look forward to see the completed project.

disneyjoe7

Beautiful work from the both of yous

george daniel

Be sure to vacuum that room before this w/e:eek:

inspiredsports

I wondered where you were Ben, and now I know.

Props go out to you, Jerry, and those beautiful cabs!

When you get all dusted off I hope you can weigh in on my post #53 at http://www.polkaudio.com/forums/showthread.php?t=74946

ben62670

george daniel wrote: »

Be sure to vacuum that room before this w/e:eek:

I was going to soak the room with gas and burn it:D
Jerry just ordered those fancy tweeters today. They will be here by Thursday:):):)

engtaz

Great job guys. Speakers look great. George, I hope your mother is OK.

george daniel

Thanks Roy,, she fine,, just at her age, she needs constant assistence/help with the activities of daily living,and my brother and I can no longer do it 24/7.

engtaz

I figured as much. Bless you and your brother for trying to. Tell your lovely wife I said HI.

ben62670

Have I mentioned I hate my camera...

Face

Nice job!