First Speakers (Fonkens) Done! Next?

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planet10 said:


I'll take some pics of a couple of the XO variations we've been playing with.

dave

That would be cool, thanks Dave.

When I built my Fonkens I whipped up a set of stands real quick. So quick I didn't let the sand I filled them with dry out all the way. Needless to say, they're starting to get moldy from the inside out.

A "two birds with one stone" solution would rock.


Ben
 
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_henry_ said:
i see there's alpairs and woofer combination on your picture.
I'm very curious how do you rate the sound? since i know you dont like the jordans :D

Yes, Alpair 5 and Silverflute W14.

Jury is still out on those. I have 1 pr of Alpair 5s and 2 pair of the earlier J6T. Initial testing has us with a preference for the FF85KeN, so we have been concentrating on it.

An MTM with W14 and FF85KeN (passive XO) is next in the queue.

dave
 
strider75 said:


That would be cool, thanks Dave.

When I built my Fonkens I whipped up a set of stands real quick. So quick I didn't let the sand I filled them with dry out all the way. Needless to say, they're starting to get moldy from the inside out.

A "two birds with one stone" solution would rock.


Ben


Next time try non-clumping/non scented kitty litter, or glass bead sand blasting media - either should come out of the bag quite dry.
 
planet10 said:


1 "mistake" i can see right off the bat ... using the rectangular PE box (which just isn't very good -- the curved one is much better (but fragile). I'd 'd be prone to using 167 instead of 166, but in that tiny box the 166 (measured data) does have a sealed F3 of about 125 Hz.

I'll take some pics of a couple of the XO variations we've been playing with.

dave

Sorry if I'm being a pest, but any info on the crossover end of the Fonkenwoof implementation?

Thanks,
Ben
 
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Thanx for the poke, i've had the pictures prepped but never got to posting them...

Here is the outside of the 2 XOs we've done so far... these are for Tysen, we haven't gotten as far along with the fonkenWoof XO (the 2nd order active Ace Audio works well enuff that it keeps getting bumped in the queue, even thou we know it can be improved on)

dave
 

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Inside of the completely passive version... this requires an input impedance of at least 50k on the mid-tweeter amp and the actual values need to be tuned for the amp in use.

Even better would be to integrate this circuit directly into the amps -- the HP could be split into 2 1st order sections.

Very simple thou.

dave
 

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And the active version... we just put a buffer on each eand of the passive sections so that it could be used almost anywhere. To keep it simple we used opAmps with battery power. Using something like the B1 buffer or a CSS-ed Cathode Follower should take it to the next level (but a lot more work).

In most situations i suspect that one could get away with just a a buffer on the end of the HP circuit.

dave
 

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Thank you. That makes it much easier for me to start understanding what's going on.

Just thinking out loud: the passive route has less parts, but would be less versatile because the values of the components in it are tied to the input impedance of the amp.

the active version is more complex, but more versatile 'cause of it's ability to work with amps of varying input impedances.

Both active and passive are before the amps, so the speakers get the benefit of more controlled damping from the amps. From what I've read, though, this implementation is not "typical" because a passive crossover is usually after the amps.

Two questions come to mind for me. First, why is it just the input impedance of the HP amp that is important in the passive? The way I understand how the values of the components are chosen in a passive crossover is dependent upon the impedance of the device it's connected to, in this case the input of the amp. Why wouldn't it matter in the LP circuit? Second is kinda along the same lines of the first, but dealing with the active crossover. Why would you need the buffer on just the HP circuit and not the LP as well?
 
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strider75 said:
Both active and passive are before the amps, so the speakers get the benefit of more controlled damping from the amps. From what I've read, though, this implementation is not "typical" because a passive crossover is usually after the amps.

Let's call it a buffered passive & a passive.

Two questions come to mind for me. First, why is it just the input impedance of the HP amp that is important in the passive? The way I understand how the values of the components are chosen in a passive crossover is dependent upon the impedance of the device it's connected to, in this case the input of the amp. Why wouldn't it matter in the LP circuit? Second is kinda along the same lines of the first, but dealing with the active crossover. Why would you need the buffer on just the HP circuit and not the LP as well?

Look at what happens when you start changing the input impedance of the amp... changing th LP amp will make no diff... but if thr you lower the value of the HP input, the resistors to ground in the passive circuit also have to decrease, and at a certain point the parallel resistors create a load for the pre-amp that worst case it cannot drive, at best you get a HF rolloff.

For the PLLXO to work best the input impedance of the HP amp needs to be large, Buffering the HP output could also be considered adding an active circuit to dramatically increase the input impedance of the HP.

dave

dave
 
planet10 said:


Let's call it a buffered passive & a passive.



Look at what happens when you start changing the input impedance of the amp... changing th LP amp will make no diff... but if thr you lower the value of the HP input, the resistors to ground in the passive circuit also have to decrease, and at a certain point the parallel resistors create a load for the pre-amp that worst case it cannot drive, at best you get a HF rolloff.

For the PLLXO to work best the input impedance of the HP amp needs to be large, Buffering the HP output could also be considered adding an active circuit to dramatically increase the input impedance of the HP.

dave

dave

OK, that makes more sense to me now.

Basically, the buffered passive would work because you'd dictate what the input impedance would be when you build it. If we could use the B1 as an example, you'd build it with a 50k pot, giving it the 50k input impedance you'd need. This way the crossover would be more verastile, if you changed the HP amp you wouldn't need to redo the values in it. You'd also gain the ability to adjust the level of the Fonkens compared to the 'Woofs, right?

Is the crossover design stage where you'd take into account the sensitivities of the 2 speaker systems (Fonkens and the 'Woofs) so their output would be similar?
 
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strider75 said:
.... You'd also gain the ability to adjust the level of the Fonkens compared to the 'Woofs, right?

Is the crossover design stage where you'd take into account the sensitivities of the 2 speaker systems (Fonkens and the 'Woofs) so their output would be similar?

So far we have arranged to have a gain (vol) control (sometimes we have had to add it) on all the amps we use for bi-amping to avoid having to build it into the XO.

dave
 
This crossover stuff's enough to get my head spinning; me opening up one of my amps that's working fine now would probably not end well.

I hooked on to the B1 idea because I've been reading up on it lately. I don't necessarily understand how it works completely, but having the schematic, PCB layout, and pictures available really help me visualize how I'd start to use it in the crossover. Fooling around with the schematic last night, I think I know what I'd remove and change. Now I'm trying to figure out the crossover itself. I understand (to a point) the differences in first order, 2nd, etc., but I'm not really certain how that translates into what would be the best bet to start with in this instance. Rather then have you tell me what to use, could you possibly point me in a direction (article, link, calculator page) to start?

Thanks for all the help, Dave. I know you're a busy guy, and all my questions are probably pretty elementary, but it is helping me to understand.

edit: Forum-wise, is it cool to conitue posting in this thread, or should I start another thread of my own?

Ben
 
strider: I'm new to crossover implementation as well. As I'm planning on going FE206 + eminence 12 I'm going to need to understand this as well. I have no issues with this discussion being continued here but I'd understand if you wanted to break your own thread out.
 
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strider75 said:
edit: Forum-wise, is it cool to conitue posting in this thread, or should I start another thread of my own?

Since this is moving into electronics, you would find more eyes to help if you started another thread...

It has been a long while since i updated this link list, so some are no doubt broken, but it might be a helpful place to start:

http://t-linespeakers.org/linx/xolinks.html

and some of the articles here might be interesting

http://t-linespeakers.org/tech/index.html

dave
 
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