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Back from the Vet and de-Wormed [message #42317] Sun, 31 August 2003 15:20 Go to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
I am so happy that they caught that spoiled arrogant little cocksucker responsible for the 32Blast Worm. He took a week out of my life.
You can't stay online long enuf' to get a cure and then a friend gives me a floppy, (remember those?) and my "A" drive won't work! Must have atrophied. Luckily, Staples 'only' charges $7.50 to burn a CD from your floppy. Kinda like selling $1.00 jugs of water for 10 bucks to disaster survivors. Oh yeah, the local 'puter shop which has seen my steady business wanted $40 to install the fix that's a free download from Symantec. Rat bastards!
But I did find a foundling at my door during the hiatus: a pair of Martinelli Horns! Bill says they're castoffs; I say they're gorgeous.
Don't know yet about the "Kraut" drivers. A little hot, Bill? BS&T never made my Molars ache before. I just now put down the iron after fastening 'gators to some 8 ohm resistors to pad them down a bit. They're glorious thru the mids, tho. Much cleaner and smoother than the whatever JBL's in the 3677s....2418 I think?
Why is it every time I think I'm there,(Altec 811's) somebody like Martinelli moves it?
Oh yeah. Is everyone as knocked out about the new Twin Towers Lord of The Ring DVD as me? Fantastic. Effects, cinematography, screenplay adaptation, wonderful. And the soundtrack! Those Nazgul lizard things.........WUMPPPP......WUMPPPPP.....WUMPPPP
Re: Back from the Vet and de-Wormed [message #42319 is a reply to message #42317] Sun, 31 August 2003 18:39 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

I checked out "The Two Towers" in the theaters, but I have a copy of "The Fellowship of the Ring" at home. Sounds like I'll have to grab a copy of "The Two Towers" too!

The latest round of mischievous programs has been in my mailbox about 100 times a day too. Seems like it was worst about a week ago, and then again two days later. I went to the websites of Computer Associates, McAfee and a couple of other sites that specialized in this sort of thing, and found that they were distributing free updates. I guess they didn't want anyone thinking they were responsible for the errant program in order to increase sales, so they gave the fix away for free. Pretty clever - I wonder how many people purchased their software anyway.

Bill is always making new good stuff, isn't he? What compression driver did you use? Are you talking about BMS?

Re: Back from the Vet and de-Wormed [message #42322 is a reply to message #42317] Sun, 31 August 2003 21:02 Go to previous messageGo to next message
Bill Martinelli is currently offline  Bill Martinelli
Messages: 677
Registered: May 2009
Illuminati (1st Degree)

Hi Bill,

Nice to see your back online! We got bombarded with that crap at work but the firewall and virus software held it off. The IT guy was steppin and fetchen though.

I'm glad your liking the horns. switch them around in different combinations. I dont know that any one combination of a horn and driver is "the best" for every song you play and through my experience I find the more revealing, defined and detailed your system gets. The more some songs sound better and some sound worse! sometimes I just dont get it.

On the BMS drivers. They are going to be much hotter. I run active crossovers so I can switch stuff in and out in a flash and adjust the gain accordingly. You basically have two small increases to deal with. First off, the wood horn will be giving you a db or two more than some other horns. Second the BMS is a hotter driver than Eminence, JBL, Altec. The Altec drivers I've tested with an FFT analyzer roll off a whole lot more than some other drivers. The BMS drivers don't roll off as much as JBL, and Eminence either.

I dont have an exact number for you, but best guess is another 4db of padding as a start point. You might like to try no bypass cap too. The ones I sent you still roll off. Not like the Neodymium models or even a ribbon tweeter which really stay flat. I think the drivers are very smooth once you get them dialed in. I like them as much as TAD's Ive heard. I dont think the JBL drivers I was using in my home system even compares, and I chose the JBL drivers over Altec, Eminence, and Selenium.

Lots of guys LOVE their Altecs, JBL's and a number of other drivers. Thats what makes this such a great country eh? we can choose!

Bill

Re: Thanks for nothing, Bill Gates [message #42323 is a reply to message #42322] Mon, 01 September 2003 06:07 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
I downloaded every XP "Critical Update" whenever they were available. I visited the update site 2 days before the Worm struck to be sure I had the patch. In typical MS fashion, it wasn't possible to determine if you had MS-30#@$%^& or not, only that the scan said you didn't need it!
"An airliner is approaching Seattle in a dense fog, at night, when all it's radar and radios go out".....................stop me if you've heard this one before.................
I put an 8 ohm resistor across the inputs and the sound really smoothed out. For those of you scoring at home, that's a total of 16 ohms on Wayne's modified Eminence 1.8k 4Pi Pro x-over.
I also moved the horns back and forth to see if that made as much difference as with the Altec 806A's. The image is a little more stable and the sound, I dunno, 'better', with the front of the horn back about 2" from the front of the cabinet.
There's no question that these BMS drivers go higher than the JBL and probably the Altec as movie dialogue is more intelligible. Listening for words, and then further for inflection is a really good test of what a driver is doing. Don't believe anyone who tells you your HT speakers don't need to be as good as for music! Just watch a Coen Bros movie to see. They are such Craftsmen. "Miller's Crossing", "Fargo", "Barton Fink", etc; whether you like their "art" or not, the soundtracks, without benefit of explosions or dinosaur footseps, are an audiophile treat.
Hey Bill, don't look for the Brown Truck until I 've had a chance to try the BMS with the 811b horns in the stillunderconstruction cabinets!
ouchie! [message #42324 is a reply to message #42317] Mon, 01 September 2003 13:35 Go to previous messageGo to next message
toxicport.e is currently offline  toxicport.e
Messages: 48
Registered: May 2009
Baron

well my pc at home runs win95 so it was safe-never had a virus in its 8year life>somehow

:')

Re: ouchie! [message #42326 is a reply to message #42324] Mon, 01 September 2003 14:06 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Parham Data does exactly what you've described at one of our smaller customer sites - They have a dozen or so PC's and the only one directly connected to the internet is a UNIX box. All the rest of them use Microsoft Windows, and they can connect to each other and access the internet only through the UNIX system.

Another attractive option is a hardware firewall, which does not have an operating system. Some are relatively inexpensive and the only software running on 'em is firmware so they're pretty robust.

Zobels on Tweeters [message #42327 is a reply to message #42323] Mon, 01 September 2003 14:13 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

If the horn proves to still be too hot, you might use a Zobel or maybe just shunt resistance. When padding a voice-coil driven loudspeaker, using a Zobel for the shunt leg of the circuit will ensure that the output from the crossover remains flat. It will also provide damping so that there is no peak in the crossover region, just like what the values of R1 and R2 do in the π circuit.

Just rearrange the circuit a bit, having series attenuation resistance before a Zobel placed in shunt across the tweeter. You can play with the Zobel values of R and C to generate the top-octave response curve that you want, and can play with the ratio of Zobel resistance to attenuation resistance to set the amount of damping, which will modify the response near the crossover frequency.

I designed the π crossover specifically to provide rising response. The intended use was with compression horns that had a characteristic negative slope in their response curves, and the π crossover configuration addresses that. Since the tweeter isn't flat, the circuit compensates so that the system is flat. It provides attenuation for level matching, top-octave compensation for the tweeter's inherent rolloff and damping of the voice-coil/crossover interaction so that it doesn't peak near the crossover frequency. But if your tweeter is already hot in the top octave, then this is not what you want.

If you want the crossover to give flat response - or less of a rising response - then a different attenuation and damping mechanism may be in order. Any time there is series resistance, this will introduce some positive slope because the voice-coil is partually inductive. Since the load is inductive, a series resistance will generate rising response. Putting shunt resistance across the tweeter will tend to reduce the slope and make the circuit have less rising response, and adding some shunt capacitance can bring slope to zero, making the circuit flat. That's what a Zobel does. Or the design can go the other way, having series bypass capacitance across the attenuation resistor to increase rising response, like the π circuit does, to compensate for top-octave rolloff of compression horn devices. So using less than a half dozen components in various configurations, you can provide a wide variety of response curves.

The point I'm making is that if you've padded a compression tweeter, then you've added some amount of rising response. You can increase it with configurations like the π crossover using bypass capacitance across the series attenuation resistor. But if you don't want rising response, then the shunt leg should have series capacitance to act as a Zobel. Adding pure resistance in shunt will reduce rising response to some degree, and it will serve to damp the circuit too. But adding a Zobel damper will bring the top octave down to match midband response, and you can completely eliminate any rising response with it too.

What he said!!! [message #42329 is a reply to message #42327] Mon, 01 September 2003 14:45 Go to previous messageGo to next message
BillEpstein is currently offline  BillEpstein
Messages: 886
Registered: May 2009
Illuminati (2nd Degree)
Hey Wayne, this is me, 780 verbal, 415 math, LOL.
I increased R2 from 8 to 16 ohms which sounds pretty 'right'.
I tried adding the 8 ohms to R1 and the sound became more tinny and hot. Like when I put too big a value on the cap. Reducing the cap value from .47 to .33 would also help, yes?
A Zobel is R and C in series? The current R1/C1 is parallel, yes? Add a Zobel in addition to the R1/C1 after or before? What values would be a good starting point?
BTW, the current set=up which I've been listening to all day, just the extra 8 ohms on R2 is really good. Definitely more treble energy which is putting out more detail but not sounding shrill or coarse. Too bad the Altec 806A are 16 ohms. It would be nice to swap them back and forth with the BMS W/O having to mess with the crossover.

Re: What he said!!! [message #42330 is a reply to message #42329] Mon, 01 September 2003 15:51 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Maybe you could make a handful of cable assemblies with different filter functions, try each of them to see which one works best. For example, you could have a "flat 10dB" cable for the Altec (16 ohm) driver and a "flat 10dB" cable for the BMS (8 ohm). Then you could also have a top-octave compensation cable for each. And maybe one in between.

I think you'll find that the cable assemblies without top-octave augmentation sound best on things like ribbon and dome tweeters, and from what you and Martinelli are saying, this may also be the case for the BMS tweeters. The π cable assemblies will sound best for Eminence, Altec and JBL compression drivers on CD horns. And something in between sounds best on Altec sectional horns - Something like a π cable assembly with C1 reduced or removed.

I think this may be what you'll find with the BMS drivers too. It will probably be something in between the flat response provided by a straight padded cable and the rising response provided by the π cable assembly. There are any number of suitable networks that will provide response in between these two, so that's where tools like Spice become useful.

Re: What he said!!! [message #42331 is a reply to message #42330] Mon, 01 September 2003 16:54 Go to previous messageGo to previous message
Bill Martinelli is currently offline  Bill Martinelli
Messages: 677
Registered: May 2009
Illuminati (1st Degree)
Hi Wayne,

I'm going to try your suggestion of the flat cable too. I forgot all about using a zobel on the tweeter. I like to use a small amount (6 or 8db) of passive attenuation on the tweeter with my active crossover. If I use just the active crossover I find the sound much more uncompressed but even adjusting the gain down 10-14db or what ever it takes. I still hear an anoying hiss from the tweeter. This is not noticable on louder listening sessions. For the lulls in classical or a movie, It becomes noticable and it bothers me.

Could you recommend specs for a something around a 5db attenuation using the zobel?

Thanks,

Bill

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