posted
Ok, my real question is when buying the components for a passive crossover, what types of components should you buy? Is there any real difference, or should you just buy the components that are closest to the values you need. Any opinions or thoughts would be greatly appreciated.
Posts: 79 | From: Palatine, IL, USA | Registered: Jan 2000
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posted
There ARE different types/ quality components that you can buy for construction of passive crossovers.. Manufacturing tolerances, material quality and other such things can determine the quality of the crossover..
In a CAR, the noise floor can obliterate some of the more subtle effects of a crossover, which can be more readily heard in a great home theater setup.
The best components that I have come across are availible through home audio DIY companies, like Havland Musi-Caps and Sledgling inductors (coils), etc. etc.. The best retailer that I have come across is Madisound, http://www.madisound.com they have a great selection of components..
however, bear in mind that the tip-top crossover can be ridiculously expensive.
ShadowStar
Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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posted
I find that by steppin up just a bit to Mylar or Polyester caps instead of electrolytics is worth it. Ditto for good air core coils compared to iron core. I buy ALL my xover parts from Solen. They have caps in a dizzying array of values and you can choose what size wire you want in your coils.
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And that's the bottom line, cuz: LORD DUKK SAYS SO!
The Big Show The Dukk says: Know your bass: PORT your damn box!! Have HoleSaw, Will Travel!
posted
Thanks guys...I have heard that some passive crossovers can get ridiculously expensive if you want them too. I was just wondering if spending more money really made a huge difference. My system isn't a terribly huge on and I was just going to make some simple high pass crossovers for my full range so I can crank the bass a little more without having the full ranges sound like s#%t. Thanks again.
Posts: 79 | From: Palatine, IL, USA | Registered: Jan 2000
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posted
To make a simple hi pass crossover.. Shoot, forgot the formula!
It's just a single capacitor wired in series with the + line of the speaker.. The value is dictated by a formula relating capacitance and resistance... Forgot it, let me look it up..
ShadowStar
Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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quote:Originally posted by ShadowStar: To make a simple hi pass crossover.. Shoot, forgot the formula!
It's just a single capacitor wired in series with the + line of the speaker.. The value is dictated by a formula relating capacitance and resistance... Forgot it, let me look it up..
ShadowStar
To calculate the correct values of capacitors and inductors to use, you need to know the nominal impedance Z of the circuit in ohms and the desired crossover point f in hertz. The needed capacitance in farads is then 1/(2 * pi * f * Z). For example, if the desired crossover point is 200Hz for a 4 ohm driver, you need a 198.9 x 10^-6 F (or 199uF)(the little "u" stands for micro, and the "F" stands for Farad) capacitor for a high pass first order filter.
posted
Thanks SS Mobile, i managed to nod out to sleep before I looked it up..
BTW- A single capacitor filter is best suited to a fixed resistance load. Because your speakers' impedance (resistance) will change over their operating frequency range, many purists would suggest (myself included) that an active crossover, such as the Audiocontrol 2xs, might divide the signals up better... But it will cost MUCH MUCH more :-)
ShadowStar
Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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posted
I dunno, I've dropped some pretty heavy cash on passive parts and stayed away from the REAL expensive stuff. The 3 way passive I made for the Mustang had $1000 in parts alone - no labor (3days) calculated! I think that could buy a decent 4ch and Xover, eh?
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And that's the bottom line, cuz: LORD DUKK SAYS SO!
The Big Show The Dukk says: Know your bass: PORT your damn box!! Have HoleSaw, Will Travel!
posted
I've found that when doing passives for home speakers you can do them well for 75-100. But the prices goes up dramatically when you need to make a crossover frequency low. The caps and coils start to get pretty expensive. I always wanted to do a single amp system in my car, but do to the experimentation time and cost I stayed away. Now I'm all active, baby.
Posts: 2575 | From: GA | Registered: May 1999
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Dukk raises a great point! I lost a sponsorship to an expensive crossover network. The guy who was gonna sponsor me had figured out everything, like how he was gonna be able to sell the equipment as demo and all that, but never took into account the 800.00+ loss on the crossover parts. I tried to rationalize with him, but he was just NOT going to actually put any real money into my car... what a cheap bastard!
------------------ STILL waiting to hear a GOOD pair of HLCD's!!
If it dont fit, force it... if it breaks, it needed to be replaced anyway...
posted
Wow, I didn't think my little question on passives would spur such a response. Thanks for all the info...for now I think passive is the way to go....my coaxs are running off my head unit and I really don't have the cash for a four channel right now. Hopefully this summer once I get home and get some cash in the bank. Sometimes it ****s being at college. Anyway, enough of my blabbering.... Thanks again guys!
------------------ Dusty Roads
Posts: 79 | From: Palatine, IL, USA | Registered: Jan 2000
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posted
Yes, passive crossovers can get outrageously expensive. Like previously said though, it all depends on how far you want to go. Oh, and on a side note; I'll just stick to the Goertz air core copper foil inductors (.15 mH = $7.85, and 6.0 mH = $47.50).
And here is a pretty good crossover calculator I found on the net. This program assumes perfectly flat impedance curves, so finding the actual impedance of the driver at the selected crossover frequency would be a good thing to look into. Here's the address: http://www.lalena.com/audio/calculator/xover/
posted
my 2 cents: Just like to add the fact that the Q of passive crossovers is much lower than it is for active. Bigger parts have worse tolerances than smaller ones. Example, a 10uf electrolytic cap maybe +/- 20-50%. A 10pf Mylar cap maybe a few percent. Both crossover designs rely on the parts haveing exact values. Especially the higher the order. If not the exact values are used the effects can be things like ripple in the pass band or stop band. And slow roll offs at the shoulder, not ot mention the wrong -3db points. I highly recomend an active crossover.
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Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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posted
IMO, I don't think you will notice a large difference between a 20 dollar inductor and a 600 dollar inductor. But yeah they can get expensive, some values are hard to find and require several components wired in series and/or parallel to get the right value.
Mr. Dank, I am not sure what you mean. It is not hard to find a 10 uf cap that is +/- 5%, or even 1%, or hell even 0 tolerance, but those expensive .
Posts: 138 | From: London Ontario Canada | Registered: Feb 2000
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posted
Usually you just have to step up to mylar or polyester to get the tighter specs. Or you can overbuy by 25% and hand match them. Never hurts to have the extras lying around...
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And that's the bottom line, cuz: LORD DUKK SAYS SO!
The Big Show The Dukk says: Know your bass: PORT your damn box!! Have HoleSaw, Will Travel!
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