I can't wait to show you it with Debian Lenny on her
BTW, you get a box of foam peanuts yet?
Cheers!
BTW, you get a box of foam peanuts yet?
Yes. Can i open it and tell everyone or do i really need to wait till christmas?
(only one thing i can think of that would be that loght and require that size box)
An externally hosted image should be here but it was not working when we last tested it.
dave
It's ok - I wired them in series. The inductance of the extra voice coil means the XO frequency/rolloff is changed a little, but it doesn't look too bad from where I'm standing.
Chris
Ok, I must not be doing something right with my simulation then as when I put my W130S in series the plots lined up. But then this is my first stab at trying to simulate a speaker so my understanding/theory is probably not all there, maths/calculations have never been my strongest skills
Would you be able to post a schematic of your crossover so I can take a look?
Ewan
Would you be able to post a schematic of your crossover so I can take a look?
Ewan
Guess where I made it...
The 4 0hm resistor is to reduce the rising top end a little - seems to do the job, as I got a lot smoother output with it than without. Still experimenting with the resistor in series, will do the same in reality aswell.
Chris
PS - around 6 ohm resistor is looking good.
The 4 0hm resistor is to reduce the rising top end a little - seems to do the job, as I got a lot smoother output with it than without. Still experimenting with the resistor in series, will do the same in reality aswell.
Chris
PS - around 6 ohm resistor is looking good.
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I couldn't possibly think where you made that......
Thanks for the schematic. After my post yesterday I went away and did some more reading on crossovers and came up with a basic 2nd order Linkwitz-Riley arrangement that worked better than my previous attempts.
I wonder if the resistor approach can be improved upon to help tame that rising top end on the FRS8M, might have a play and see what happens.
Ewan
Thanks for the schematic. After my post yesterday I went away and did some more reading on crossovers and came up with a basic 2nd order Linkwitz-Riley arrangement that worked better than my previous attempts.
I wonder if the resistor approach can be improved upon to help tame that rising top end on the FRS8M, might have a play and see what happens.
Ewan
I find it's trying to get rid of the 10kHz peak that's difficult - I've tried inductors at various frequencies, but nothing seems to tame it too well, also, 6dB/octave is too steep. What I need is some kind of 3dB/octave thingy. I'm considering the purchase of a graphic EQ, but at £100 for something half decent, it's not cheap.
Chris
PS - 1st order for the woofer (as recommended by Dave) does seem to give the best response. Might move the FR XO down a little to cover the dip around 250Hz.
Chris
PS - 1st order for the woofer (as recommended by Dave) does seem to give the best response. Might move the FR XO down a little to cover the dip around 250Hz.
Hi Chris,
so the 10k FRS8M peak is bothersome then.
a well known 'notch' here -> Parallel Notch Fliter Designer / Calculator
(might require tweeking), or maybe use a very cheap tweeter from 8kHz Ist order?
just trying to help, Grant .. I'm keen to buy 2 of those.
so the 10k FRS8M peak is bothersome then.
a well known 'notch' here -> Parallel Notch Fliter Designer / Calculator
(might require tweeking), or maybe use a very cheap tweeter from 8kHz Ist order?
just trying to help, Grant .. I'm keen to buy 2 of those.
After playing music for a while longer, it has settled down.
Looking at the response charts, it's pretty similar to the FRS8, with with more sensitivity. Using the FRS8, I didn't notice the peak, and, now they have bed in properly, I don't notice it now.
Messing around with XO points. If you bring the woofer XO up a little (6.6mH for both in series), you fill in the dip at XO point that was there before. Only done this because (for the one woofer per side I have) I only had 3.3mH inductors left, so I put them in anyway, then went off to figure out what they did.
Chris
PS - I'd suggest buying them. They're small, good efficiency and sound great.
Looking at the response charts, it's pretty similar to the FRS8, with with more sensitivity. Using the FRS8, I didn't notice the peak, and, now they have bed in properly, I don't notice it now.
Messing around with XO points. If you bring the woofer XO up a little (6.6mH for both in series), you fill in the dip at XO point that was there before. Only done this because (for the one woofer per side I have) I only had 3.3mH inductors left, so I put them in anyway, then went off to figure out what they did.
Chris
PS - I'd suggest buying them. They're small, good efficiency and sound great.
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Currently, I have a fair of FRS8Ms in sealed (1.5L) enclousure, and a woofer per side, with an XO that needs values which are closer to what they should be (I used stuff which was lying around.
The sound is good, so I'm looking forward to making the final pair (should be some time this week, as it's half-term so a full week to myself).
Thank you to all involved with advice, critisisms, etc - this couldn't have been done without you guys.
I'll let you know how the build goes.
Chris
The sound is good, so I'm looking forward to making the final pair (should be some time this week, as it's half-term so a full week to myself).
Thank you to all involved with advice, critisisms, etc - this couldn't have been done without you guys.
I'll let you know how the build goes.
Chris
Nice work on the notch filter, I had tried implementing one using the calculator posted earlier but like you discovered that it didn't seem to perform properly in boxsim.
One quick question, as you mention you have the FRS8Ms in 1.5L sealed enclosures have you decided to ditch the TL approach of the original Tysen design in favour of a sealed enclosure?
Good luck with the build and I'm looking forward to seeing how it turns out.
Ewan
One quick question, as you mention you have the FRS8Ms in 1.5L sealed enclosures have you decided to ditch the TL approach of the original Tysen design in favour of a sealed enclosure?
Good luck with the build and I'm looking forward to seeing how it turns out.
Ewan
I've been playing around with the 'classical' transmission line alignment tables provided by MJK and the FRS8M specs, but since these tables weren't designed for drives with Fs greater than 70Hz I don't think the results are that meaningful. For a 10:1 taper it suggests a ~40cm line going from 285cm sq. to 29cm sq. I guess the only way to properly model a TL for the FRS8M would be to invest in a copy of MJK's Mathcad Worksheets for TLs, but for a single TL design this might be overkill.
Experience is always useful, especially when building something. I know from building the Portraits what issues to look out for in my next speaker build.
Ewan
Experience is always useful, especially when building something. I know from building the Portraits what issues to look out for in my next speaker build.
Ewan
2nd pair of woofers today.
Bedding in nicely, using my usual test cabs.
The problem with using 5" woofers is that you need several to get any meaningful SPL out of them. They go low, but not that loud, but with 4 of them, you can move the equivalent to a 10" woofer, which is a decent amount of air.
Put this way - you can see them moving at a decent listening volume, without looking too closely, with 1 per side.
Chris
Bedding in nicely, using my usual test cabs.
The problem with using 5" woofers is that you need several to get any meaningful SPL out of them. They go low, but not that loud, but with 4 of them, you can move the equivalent to a 10" woofer, which is a decent amount of air.
Put this way - you can see them moving at a decent listening volume, without looking too closely, with 1 per side.
Chris
Your diagram is correct - the peak begins at ~8kHz, and finishes around 12kHz, with around 8dB peak centred at 10kHz.
If you do a sweep, this is audible. Listening to music, however, and you can't tell it's there.
Definately the best I've seen for the price.
Talking of prices, I saw something neat reading through a HiFi mag...
The Arcaydis AK3 uses the same bass driver as the one I'm using ( http://www.arcaydis.com/images/AK3.jpg ) They retail at £600, which begs the question - where does the other £580 go?
Chris
If you do a sweep, this is audible. Listening to music, however, and you can't tell it's there.
Definately the best I've seen for the price.
Talking of prices, I saw something neat reading through a HiFi mag...
The Arcaydis AK3 uses the same bass driver as the one I'm using ( http://www.arcaydis.com/images/AK3.jpg ) They retail at £600, which begs the question - where does the other £580 go?
Chris
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