Good advices for a newbie (threading tools lathe)

[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.

[PJs]

Well Said C-Bag!! I too think it is a bit hard to stay on topic (building a pair of cone drivers) but it is the physics and Stefano's "Verve" that light the candle for me and spins this off in all directions imho. I woke this morning thinking that I don't really have the skill set to even attempt a speaker enclosure like you want. Frankly I'm having a difficult time as it is just building a hand crank/solar powered music box that is acoustically "reasonable" and bullet proof for my G-Son. And Honestly I'm quite enamored/jealous with you having a pair of ESS's. I had an old pair of Series 5's for a while but had to let them go for space and needed a small lift to move them.

I'm with both of you on the Klipsh, tinny to my ears and no heart. Never got to hear the Ohm F's either but they were a wonder and still pretty much top of the line at ~$8k for the new ones, but hey...they have a Beta program!! ~¿@

I've always had a broad taste in music, from classic, Blues, Jazz R&B, Bluegrass, & R&R but over the Ages moved enjoy videos/movies tremendously. It's a heck of a load to put on a system, IMHO and all about the best for me within my budget & space. I go on small binges of listening to things like Les McCann and Eddie Harris to Liz Story solo (melt me) to a DVD set of Eric Claypton's Cross Roads Festival with a Goose bump & jump version of Joe Walshes "Mountain Way" in 5.1 (one of the best ever Music DVD/Festivals, IMHO). Then there is always Jimmy's Voodoo Chile on Vinyl...Oh My! Then back to Beethoven 7th...but Movies are probably the mainstay anymore...And would somebody Please teach the Foley/engineering guys how to balance tracks for Gosh Sakes.

I ended up with the Bronze Br6 towers & set (Center and Rears) for my system partly for price but mainly because it handled Liz Story's Steinway better than anything else. However I added a pair of Bose 301's I had, high up & tied to the fronts (Front B), mainly because of my room shape and size and they brought a little brightness. I'm not a big Thumper guy and only have a little Sony 10" sub which will literally rattle the windows in this old place and fine for my tastes. I agree that balancing the room and system is second only to matching the system components and Cables/connectors too. Probably spent 3 days learning & messing with mine to get it all right for my tastes...after break in. Which is one of the thing I appreciated too about the Monitor Audio's was the booklets gave a methodology for break in...absolutely necessary IMHO.

I took a look at the SMAARTLive and it's quite a package but pricey, and the dbx 260 is quite impressive. Think it will Do!!

Stefano: curious why you would us 6mm (1/4") brass plate for a panel mount? Although "Pretty", AL rack panels are my favorite and easy to work, and you could have a small piece like that gold anodized pretty cheap I would think. I agree with C-Bag about using a fly cutter for boring a big hole. Probably the other reason you got chatter is because of the air gap under the middle...would recommend a sacrificial piece of AL or even wood if you don't have that. Probably a better way would be to drill a large hole and use a boring bar to take it out to size. Don't know if you have one though and get using what you have on hand.

Till Then Guys...Thanks for the candle lighting and fun topic(s)!! ~PJ

[rendoman]

Thanks for advices! I never seen in music or electronic shop front rack panel, but i see on some sites that they are cheap! a bit professional look, but practical! I used brass because i found some good plates from scrap shop. here it's difficult to find metals, hard to find metal in the size you want, and pretty impossible to find them at good price I really like sturdy frame, massive and good looking. For sure 99% of my projects are oversized!
It's work for next days, the frame will be composed of:

- steel 15x15mm thick 2mm for the real frame
- top plate frame (base for the 3 tube socket, for transformer, horn and primary coil) in 1,5mm brass, 2 parts wide 10cm each and 35 cm long
- 316 perforated steel as faraday cell for coil ( have to think how to bend and create a nice looking one )
- bottom and lateral, for cover and shield, steel or alu 8\10

I think it's a bit difficult to imagine the frame, i got all in my mind, i will show you soon! ( i hope! )

to be honest, i only have two broken and repaired old tools, one is in the last pic (and it's the only one that make big holes), the second is a boring bar in fact, with a small square blade, i think it drill till 22\23mm, but the body of the tool require a large hole to fit... for sure my method is wrong, but i think i need to make some other tools.... but we here in the right place for making tools right?

I took a macro of the blade after work... maybe because my fault, i let the tool gets blocked 3 times, i missed the outer part of the blade... but it's still working!
For the next holes i'll follow your advice to grind better the tool, and to put some wood under the plate, you're right i leaved too much air... i didn't want to hurt the milling machine, basically i'm noob
and in second pic... ready for polishing again!!
the last 2 pic are the new camera just arrived this afternoon, for sure some of the next pics will be better than my broken old one I used a ticket from ebay, 70 euro on 100 of minimum buy, in few word 70% if i spent 100 or more! I received this ticket half jan as many other people, but ebay says that was a software error. I wrote to customer care of ebay and after a couple of week they give me the same (true this time) bonus! If someone of you received this bonus, i recommend you do the same with customer care

[C-Bag]

Watching this thread evolve it's funny how you say it's hard to find the metal you want at the price you want, but you always come up with some good looking stuff. I would recommend an import clamp kit and probably a 4" knock off Kurta style vice both for the mill. They are basic tooling for the mill and make work easier and safer.

Making an enclosure for a custom piece of electronics is a real challenge. I've only done one and that was enough. I bought a strip unit of 4 mic pre's out of an old Quad 8 mixing board. It supposedly came out of a board that was in a famous recording studio in LA. I had a really hard time finding a case and then fabricated a front panel for it. Came out looking very vintage I put the power supply in its own box, out board for isolation and because it was too big for the case.

When I was working as a mechanic/ fabricator/welder in fruit packing here in the Central Valley of California, I was always up to my neck in metal. And I could take home scrap out of the recycle bin(within reason) for free. The last company I worked for had a HUGE what we called "the bone yard" that was full of out dated equipment. There was probably 10 huge rack cabinets complete with rack rails, mounts, and screws. But even though I was not that great of a wood worker, I ended up making my racks out of wood. Because I didn't want to have to isolate each unit from the rack because of ground loops. I've made several racks for my PA and recording equipment and all the rack units were wood rack rails. Never had any problems with ground loops, hums and buzzes.