Good advices for a newbie (threading tools lathe)

[rendoman]

I went to the dark side 6cm drill buffer, and a home made not good small buffer for the inner part... i hope monday i will find some better commercial new one. polishing with drill maybe it's the better way to do this job, now the horn is shining more than in photo. I hope i'll finish the first flange and do some test! See you on the next episode

[rendoman]

Hi! it's long time since last update ,I got a long flu and had to do other works unfortunately
I still have difficulties finding a tiny buffer for the small inside of the horn, dremel cloth insert are too short and I see that for polishing i need to press a lot. I will have the same problem for the next small horn of only 1cm throat ... i need to find something!

apart polishing, i mounted driver-flange-horn for some test, sound is really good to my ears very detailed and focused! i build a simple rod for microphone, i'm waiting the key of a beta test program (medianet audio pro solution), hope that program is easier than "speaker workshop" who needs specifics cables with test resistors and an Lcr bridge.

OT: i'm planning a plasma tweeter
OT2: i found a box with Emergency button in scrap, i added last night a contactor, need a bulb light for voltage presence. I mounted on my lathe, it didn't have the Emergency stop

some pics as usual, the third photo is a generic layout of the new plasma speaker (horn will be 1\3), fifth pic it's a rat9 big mouse for size comparison

[C-Bag]

Funny, i was just wondering about what happened to you yesterday Stefano! I guess that cold shop got to you I'm glad you are over your flu and back at it.

Good pix as usual. As to a polisher, have you seen those special polishing balls for polishing aluminum wheels on cars. I think they have tapered ones.

I have one of those Berhinger mic's and I believe because it's omni directional, it needs to be mounted vertically. I could be wrong. The whole sampling/testing/pinking the room is a very tricky thing I learned from my buddy who does pro sound for a living. From what he told me you have to be kinda close to get more of the speaker and less of the room. Im sure PJ's knows more about this than I do and will be along soon and enlighten us both.

Great score on the control box/ emergency stop! What a find.

What I'm wondering is how to make some kind of pantagraph/ duplicator for your lathe to duplicate the next horn. I would think it pretty critical to make them the same. Anyway good to see you back, carry on!

[PJs]

Hi Stefano and C-Bag! It is good to hear from you both and glad you are over the flu...there was a nasty one going around here too.

I like C-Bags idea for the buffer ball/cones. Generally they are mounted on twisted wire which you will need to be careful with. Probably wrap it with several layers of tape and maybe some foam too? I was also thinking of using a boring bar type that you could mount on the cross slide and compound to work it in with some pressure...although if you use your compounds wisely you shouldn't need a bunch of pressure.

I took a look at the medianet program and looks pretty good but they don't give a lot of details. When I did my sound table I used TrueRTA (24 octave version) for my spectrum analyzer and found it quite easy to use, accurate (as you can be with a sound card) and mainly it has a capture feature that ports the data to Excel which was what I wanted. Lots of good settings and options but it is important to create a configuration file with your equipment to give it a base line.

As far as the mic goes I pointed it downward into the flat table. Not sure if this was correct but the db level dropped off drastically when it was perpendicular to the table. The tricky part is placement distance IMHO. For my application I needed to take 3 different heights from the table face (1", 3" & 6") in a 4" grid pattern over the table surface. Speaker measurement is another story and believe the optimum measure distance is either 1" or 1' (C-Bags friend would know better I'm sure). Room measurement is a whole other ball game!! The other most important part is what you are driving it with and how. I drove the transducers with the HP 4ch signal generator through the Art4 amp while monitoring at the transducer on my O'scope for input levels.

The direction curve for the mic is quite good and in reality it is well suited for room correction work but there is hardware/software and algorithms for analyzing the acoustics levels for optimum placement based on the responses to specific frequencies, pulsed, sweeps, pink/white, etc. My Marantz system has the feature built in and came with a mic. The interesting thing is it has multiple algorithms and storage options. Hard for me to get my head around it. Although I played around with building a voice analysis system to identify frequency/db ratios by octaves and to show harmonics as a subset...had to put it down finally but still think it's doable and may be worthwhile for determining stresses within the body/spirit/mind. Tuvan throat singers can actually create a binaural beats and IMHO is why it "feels" so relaxing or invigorating and adding that to an instrument or other singers in harmony or "disharmony" can invoke an amazing "well being" or health.

Ha!! C-Bag...I'm with you on the Pantograph. Ever since I saw Keith Fenner creating the boat rudders I have been on the hunt for how to do that!!

Looking forward to what you come up with Stefano...Plasma...Oh, My...shocking!

[rendoman]

Hi all! nice to see you
The flu this year is really long, 2 weeks of weakness

thanks for the good advice powerball, i think i'll search for something similar here, maybe I will be lucky and I will find a good store!

I found some time ago this site from italian, he uses speaker workshop. I see many passages for calibrations with special cables and test resistors 1%. i see in freq response the same mic position is the same, radial the speaker... but don't know why, have to read better
Claudio Negro's home page, how to project and test a loudspeaker using Speaker Workshop

I think too, it will be so hard to duplicate... i will do a "mask" my purpose is to make the second similar, not a perfect clone, by hand is difficult to replicate exactly and maybe it's not completely necessary...
how is a duplicator for lathe? i already heard of this but never seen one

today arrived all the basic parts, capacitors, resistors, sockets. i made coil in teflon - delrin

[C-Bag]

I stand corrected on the mic, sorry guys. Mine came with my dbx DriveRack 260 and only one time did I ever have enough time to use it for the auto eq and thought it didn't work all that great.

Sounds like not only was I too far away, it might have been pointing wrong....doh! I'll slink back to the peanut gallery again now......

[PJs]

Sounds like not only was I too far away, it might have been pointing wrong....doh! I'll slink back to the peanut gallery again now......

C-Bag - Front and center Please sir! Your thoughts are tied into this project as well and good ones at that! I have no idea that my methods are more correct than anybody elses other than a bit of research, however it did seem logical to me with the equipment I had and playing around before actual testing. The things I was looking for was a solid coupling of the transducer and any issues with harmonics/distortions from the table components.

I found some time ago this site from italian, he uses speaker workshop. I see many passages for calibrations with special cables and test resistors 1%. i see in freq response the same mic position is the same, radial the speaker... but don't know why, have to read better Claudio Negro's home page, how to project and test a loudspeaker using Speaker Workshop

Stefano: I saw his website before but didn't delve into the minutia. From a cursory stand point it seems pretty complete except for doing it in an anechoic chamber and based on the equipment he had at hand ("Old Sound Cards"). It also looks to me he did a far & near field test (1-2m & .055D) which makes sense to me because of the dispersal curve of the cone/speaker.

As far as duplicating the second unit...all you can do is measure, measure, measure, and then maybe adjust the filter to compensate and balance the pair...if that is even necessary.

I always want to know how it sounds in a working setting most of all. When I bought my Marantz I must have listened to 10 sets of different speaker system with music that I brought for testing. Finally choosing the Monitor Audio's that best fit my tastes and music/video...& Budget!

Interesting design and nice work on the Delrin cores. Thanks! ~PJ

[C-Bag]

C-Bag - Front and center Please sir! Your thoughts are tied into this project as well and good ones at that! PJ

Aye aye Mr. Wizard sir!

I'm always ready to learn, or unlearn. My lack of focus though tends to make me truly a master of none, knowing just enough to be dangerous.

But I'm fascinated with Stefano's energy and verve! Makes me wonder if you ever sleepStefan! I do get a lot of ideas and energy for moving ahead with my audio dreams of building some new speakers for my own old stereo rig. My problem is just picking the best direction as I have from 1k to 22k covered with my EES Heil's.....it's all about trying to find the best cabinet/speakers for everything below.

So the peanut gallery is paying attention!

[rendoman]

thank you! you're too kind! I'm Learning new things every day!

I always want to know how it sounds in a working setting most of all. When I bought my Marantz I must have listened to 10 sets of different speaker system with music that I brought for testing. Finally choosing the Monitor Audio's that best fit my tastes and music/video...& Budget!

If I understood well, your point is how to make them sound good, in whatever setup, right? I got your same impression with commercial type finished product. I listened to many different kind of speaker and mix of amp and source, in different rooms. I have to make a summary because is too long, imho room is important, but not so important as mix speaker + amp (i keep the source apart for now). A short consideration of commercial "mid cost, low-mid size speaker (including half new production of klipsch for exemple, excluding la scala and klipschorn Heritage) imho they sound bad as hell. I have always the sensation they sound strange in voice, mid and highs, anemic. Maybe that's the compromises for space, It is a coincidence but I never heard sound bad a "big and well made" commercial speaker, even in small room with square map. the first exemple I remember i listened a pair of tannoy Westminster in a ugly room.
i think one thing, usually I play with separated parts, not a complete and finish product, then i have the possibility to choose the range and the loading of every components. It follows that if i can choose size, loading, number,type of driver and enclosure, I can setup them every time in a different way, and find the best sound to my ear. ( and to any room )

imho there are some few problem in most commercial speaker, i try to synthesize:

- new house have small room than old, than the need to use compact systems, and make them sound "good" in many rooms.
- good, fast, efficient and deep bass need high volume and at least a 15"
- factory can built speaker with 2-3 ways, but the problem is the range they use for every way. for me it's not good use a bass unit up to 500hz, when it overtakes this point the bass suffer and the mid even! I tryed xover of 10\12 and 15" at 1000-1500hz, no, they were bad over the entire range. It is the short blanket

after many attempts i choose to have the best for every range. true low bass, the woofer should be a true woofer, not a woofer used till Death
the second things i like is to use a fullrange for voices and mid (also in normal reflex box, horn is my passion but a reflex can be good) just to avoid a crossover in critical fq range.

summing up to the maximum: single good parts with a good active xover and some wish to make listening tests make the speaker sound maybe different from a finished product with few possibility to setup

But I'm fascinated with Stefano's energy and verve! Makes me wonder if you ever sleepStefan! I do get a lot of ideas and energy for moving ahead with my audio dreams of building some new speakers for my own old stereo rig. My problem is just picking the best direction as I have from 1k to 22k covered with my EES Heil's.....it's all about trying to find the best cabinet/speakers for everything below.

many thanks! if i may give you an advice, heil are so good!:
- one ( or better 2 ) 15" with good box, 20-30/ 150-200hz , 96 ore more db
- a couple of small and economic fullrange (even westra in open baffle), an or fostex, or an esoteric lowther pm4 units (one of my dreams) from 200 to 8-10k
- heil ( yes i don't want to use from 1khz )

with reflex good box, or open baffle or other similar loading they are easy to make, sound good and there isn't a great difference between sensivity of speaker. maybe the expensive parts are 15"woofers and coils (you can do) for 200hz filter...

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after this lengthy discussion, i got some problem:
I tried some hours ago to drill some 6mm brass plate, ugly as hell! I don't know why but with good drill, near to exit the hole, the plate tried to lift wildly. I found an old broken and bad repaired flycut (it's flycut the name?), i tried to grind a broken threading tools, it cuts "good", but make bad sound.
I also have the impression that i should learn how to block parts on milling ...
ok beat me, I deserve it I make bad works sometimes

a couple of new pic, i decided to put the 2 switch, one for filament and "low" 350v anode for modulator, and the second for the main B+ grouped to the left of ammeter. The big hole should be 45mm, in pic is 43mm.
I think next days i will complete the stands for the finished horn, then i will make some more test

[C-Bag]

Always so much to cover on your projects Stefano. I guess we could argue that speakers are tools for listening to recorded music...you are certainly using a lot of tools!

The Wiz makes an excellent point about so many factors in selection of equipment is mind boggling alone. But then when you add in real world application into your room it gets overwhelming. The added factor I now have is I can't have a setup that dominates the living room like I used to and don't listen at concert levels anymore. Much more modest. And my system is made for listening to acoustic music.

I so appreciate your opinions and advice Stefano. And especially your opinions on other systems as that lets me compare to my experience with those same components. I totally agree with your accesment of Klipsh and I think of them when I think of horns. This only makes me wish I could hear your system even more.

I also tend to avoid multi crossover/speakers as much as possible I think that's why I love Heil's, Magnaplanars, electro stats etc. I always wanted to hear a set of Ohm F's but never did. But all those speakers lacked authority in the bass. ESS sounded good for jazz but never seemed to have "thump" for rock. Passive radiators just sound kinda mushy for below 50hz IMHO. 2x15" or 2x18" in a folded horn cab is pretty good for PA but totally impractical for home For me the 15" sounds to slow( the only way I know how to put it) for home. I'm stuck on 2x10" transmission line or baffle like the old Dynaco A50's. But I've not heard either in 30yrs, and unlike you Stefano, don't have the time and passion to throw into building either and find out things have changed. #1 being I don't listen to that kind of music anymore.

My idea now is to be able to build the low end, then bi amp through the dbx 260 DriveRack and do all the time alignment(VERY CRITICAL) and eq(it has separate notch, parametric,and graphic eq for each output) in conjunction with SMAARTLive to do all the realtime analysis.

As far as I know a flycutter is more for milling flat surfaces, not for cutting holes like what you are doing. Your hole saw is a good way to do brass/copper. I would grind the cutter itself to cut narrower and have a pretty flat rake to it. That's why drill bits don't work to well because they have too aggressive a rake to the cut. It's fine until like you said, the very end it takes too big of a bite and try's to destroy itself.