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Old 16th August 2005, 06:24 PM   #21
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Location: Bremerton, WA.
I guess I mean passives. You would be looking at the same thing as a two-way speaker with an internal crossover, except the Fostex would be in one box and the woofer would be in another, and you would have four speaker wires running from the panny for both channels. The thing I don't know is if the Panny would handle the crossover work. We already know the Panny has bass management in multi-channel use but does it do it in two-channel, bi-amped mode?

As for expense, sure, you could spend $500 building a passive crossover for a two-way speaker. You could also do it for $20. Depends on how much money you have.

Regal, my entire input in this thread is based on the idea of bypassing the plate amp on the subs entirely by using the bi-amp mode on the Panny. Everything you wrote in your first post made excellent sense. I'm just seeing if it can be done even simpler and cheaper.

Doug
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Old 16th August 2005, 06:54 PM   #22
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The Behringer 2496 puts it out of what I consider, budget territory. I looked at buying one previously, but I can't find it for under $230 anywhere and I've got more important things to buy before I drop that kind of money on an equalizer.

As for cheap amplification for the subwoofer, why not use one of the more robust Tripath based designs from 41hz.com? An Amp1 or Amp2 would have plenty of power for a pair of subwoofers. They're pretty cheap and power efficient too.

Considering a budget solution would use a driver along the lines of a 126/127 or 166/167 (which is pushing it for a budget system), you'd want to cross it in the 100-200 range, which means you'd probably want stereo subs. Crossing at 150-200 would make passive affordable, much more so than using a Behringer. Sure, you wouldn't have all the equalization, but you're looking at doubling cost of the system if you go the active route.

Then again, there are always plate amps that do a decent job. Pair it with a Tripath amp for the Fostexes and you're good to go for a pretty small sum of cash.
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Old 16th August 2005, 10:17 PM   #23
regal is offline regal  United States
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The other issue with using a passive crossover would be matching the SPL og the fostex with a sub it would probably require alot of attenuation which may take some of the majic away from the fostex.

I am going to try this with a plate amp at 150hz but it will be mono but I will using 2 subs one under each speaker so localization won't be a problem. I really don't think there is much stereo material on recordings below 200hz. If I don't like the way it sounds I can lower the crossover to 100hz and build BR boxes for the fostex's in lieu of sealed .


Funny you mentioned the AMP1 at 41hz.com. I looked into it but building a power supply isn't something I am up to. It requires an oddball expensive torroidal transformer (22x2V 300VA) that costs more than the panasonic reciever alone.
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Old 17th August 2005, 01:01 AM   #24
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Well, that's if you use the PSU design on the 41hz.com website, but I suppose the PSU would be pretty pricey regardless of design used. I didn't think that far ahead. A plate amp is looking pretty attractive at this point. Especially if it has an adjustable crossover.
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Old 17th August 2005, 02:39 AM   #25
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A cheap Yamaha computer sub I bought off ebay has an adjustable crossover, and it works on both speaker level inputs and line level inputs. So if almost every plate amp ever made has an adjustable crossover, why would it be so hard to build your own and then use the Panny's amps to drive the subs?

This is where I stumble on this whole idea. Why buy more amplification when the Panny (for example) has seven amplifiers?

We're still talking about a low-cost, two-channel music setup, right?

Doug
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Old 17th August 2005, 03:03 AM   #26
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I was thinking a sub amp and T-amp combo, rather than use the Panasonic in combination with another amp. I'd rather not use the Panasonic at all.

But I think amplification is a totally separate issue. I think the main purpose should be to select drivers and enclosure(s). You can amplify the system however you like. At this point the bass driver to be used hasn't even been established yet and the use of the Fostex FE126E/127E is still tentative, and it'll probably be in a sealed, but maybe it'll be in a BR enclosure. Of indeterminate design. And yet crossovers and amplification are already being decided upon. Though no one knows what it's going to be powering yet. I got caught up in it, but shouldn't the drivers and enclosure be decided upon first?
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Old 17th August 2005, 03:49 AM   #27
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I'm trying to get my head around all this. This is what I learned tonight:

For proper bi-amping, the crossover comes before the amp. Example: Source/preamp-->crossover-->amp--->driver.

So unless the panasonic does active filtering in bi-amp mode, it would not work. I was thinking you could just stick the crossover in the speaker wire to each driver, like a passive crossover. This won't work as you lose all the benefits of directly amplifying each driver.

It seems to me the crossover is the all-important link in this chain. After the crossover, you can use any amp for the drivers.

I checked prices on active crossovers. The Behringer is so popular because it is about the cheapest available. There are some kits, however, as low as $75, but you can't just turn a dial with these.

A plate amp with a both a high and low-pass filter would be ideal (you chose which one you want). Four of those, and you would be in business...I think

Doug
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Old 18th August 2005, 02:23 AM   #28
el`Ol is offline el`Ol  Germany
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Default Re: ultimate low cost FR system

Quote:
Originally posted by regal
I don't think anything can compare to a fostex up to 10x the cost as far as the fostex drivers. This system I propose is not a true single driver system but I believe it makes more sense than TL or horns. The technology is there why not use it?

Start with a panasonic digital reciever SA-XR25,45,50,55,70. These are highly regarded.


I am using the SA-XR30 with the Ciare CH250 and I tried it with the FE126. The Fostex doesn`t come close to the Ciare in detail resulution, no chance. I never heard the larger fostexes, only a 16cm custom made by Fostex for Loth-X and its resolution isn`t so good, either. I don`t have woofers, yet, but I am considering the Eminence Alpha 15 in OB.
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Old 18th August 2005, 02:31 AM   #29
el`Ol is offline el`Ol  Germany
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Quote:
Originally posted by JWFokker
I was thinking a sub amp and T-amp combo, rather than use the Panasonic in combination with another amp. I'd rather not use the Panasonic at all.

But I think amplification is a totally separate issue. I think the main purpose should be to select drivers and enclosure(s). You can amplify the system however you like. At this point the bass driver to be used hasn't even been established yet and the use of the Fostex FE126E/127E is still tentative, and it'll probably be in a sealed, but maybe it'll be in a BR enclosure. Of indeterminate design. And yet crossovers and amplification are already being decided upon. Though no one knows what it's going to be powering yet. I got caught up in it, but shouldn't the drivers and enclosure be decided upon first?

I tested the T-Amp, really not bad for the money, but don`t compare it with a Panasonic. When it has to be the T-Amp the small fostexes are a good solution, better than the Ciares. In contrast to the T-Amp the Panasonic has variable voltage for the output transistors an will sound good at any level.
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Old 18th August 2005, 05:29 AM   #30
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I hope you're not referring to the stock Sonic Impact T-Amp. In it's stock form, it's very good for the money, but not great. The Sonic Impact amp uses pretty cheap parts. You should look into trying a higher quality Tripath amp, along the lines of an Amp3 or Amp6 from 41hz.com or the Tripath based amp from DIYParadise.com.

http://www.41hz.com/main.aspx?pageID=105
http://www.41hz.com/main.aspx?pageID=118
http://www.diyparadise.com/charlize.html

Of course, the Amp3 is primarily SMD based, so unless you're into that sort of thing, it's a PITA. I toasted mine because I don't have the hardware to assemble SMD parts. I did make a number of modifications to a Sonic Impact T-Amp, and the result was considerably better than stock form. With an Amp3/Amp6 or the Charlize amp, no modification would be necessary. I plan on picking one up in a couple weeks to replace my modded T-Amp.


As for the Ciare CH250, the comparable Fostex would be the FE206. It's quite similar in size, design and efficiency. However, it's about 3x the price. I don't doubt the Ciare is better than the FE126. The problem I have with the Ciare is that it's only available in Europe. It looks like it's a good deal at about 50 Euros (what I was able to find), but I can't get it, as I'm in the US. Fostexes are available worldwide however.
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