Hi Adason,
Thanks for the kind words. I think I would like a lower xo point as well and the woofer falloff needs to be steeper to reduce effect of coloring the mids produced by the full range.
I may have to forgo the whole transient perfect business for now and do something like a 2nd order on woofer to get a cleaner separation of woofer and teeter. Although I don't know how practical that is going to be given how big inductors need to be at 300Hz XO frequency. Perhaps some iron core Erse's circa 20mH may fit the bill. Although I think a second order and first order can be made transient perfect as it is half of a B&W hole filler XO?
Thanks for the kind words. I think I would like a lower xo point as well and the woofer falloff needs to be steeper to reduce effect of coloring the mids produced by the full range.
I may have to forgo the whole transient perfect business for now and do something like a 2nd order on woofer to get a cleaner separation of woofer and teeter. Although I don't know how practical that is going to be given how big inductors need to be at 300Hz XO frequency. Perhaps some iron core Erse's circa 20mH may fit the bill. Although I think a second order and first order can be made transient perfect as it is half of a B&W hole filler XO?
>>> The distortion is very low and the mids and highs are very clear with no sibillance.
X, are you saying the FF85 doesn't sound sibilancey? I got into full range drivers in an effort to reduce sibilance typical two-ways I was building produced. Now I'm super curious to compare the FF85 to the Dayton PS95-8 (too trebly) and Vifa PC9 (not trebly enough, IMHO).
Setting the crossover around 600Hz reminds me of the dome mids used by Acoustic Research and ADS years ago. I always enjoyed those speakers but thought they had a mechanical sound (that I always attributed to the mid-dome).
AR(Acoustic Research) AR-91
Thank you X for making the time for this thread.
X, are you saying the FF85 doesn't sound sibilancey? I got into full range drivers in an effort to reduce sibilance typical two-ways I was building produced. Now I'm super curious to compare the FF85 to the Dayton PS95-8 (too trebly) and Vifa PC9 (not trebly enough, IMHO).
Setting the crossover around 600Hz reminds me of the dome mids used by Acoustic Research and ADS years ago. I always enjoyed those speakers but thought they had a mechanical sound (that I always attributed to the mid-dome).
AR(Acoustic Research) AR-91
Thank you X for making the time for this thread.
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I also agree that a second order for this kind of comparison seems inevitable and even if you were doing a second order on the bass and a first order on the mids you couldn't lower the crossover much. Since we're trying to hear the ff85wk specifically I think a second order around 250-300 hz would be best and would still minimize excursion. I'd also be interested in seeing your opinion of how a 1st order at a higher frequency sounds compared to a second order
That is the easy way out and I know I can do that in 20 minutes (fail safe plan) 😀
However, there are those who complain that my miniDSP muddies the picture with its cheap DAC and ADC. And there are those who believe that the signal should be as direct as possible from source to driver. In order to keep the signal as unadulterated by cheap DACs and ADC's as much as possible, I thought going with analog amps (either class A or class AB) and passive XO's to skip the active DSP bi-amping chain might get me results that are a little more acceptable to the detractors of this whole "blind testing over the Internet" business.
The biggest reason though for a passive is that I want a passive speaker to use to use a test speaker my new fascination with building class AB and class A amps (I am on my 6th one now), and it forces me to learn a new skill in designing passive XO's.
I may not succeed at a good (or affordable) passive XO as I am seeing all sorts of complications that is driving the parts count of coils and caps up and up...
I will give it a good shot though and lets see how it sounds.
Have you tried using the minidsp to optimize the crossover and then build a passive one? Just throwing components around can be hard as it seems you're finding out haha.
Also does that amp you have have a bias adjustment? I assume it does so you could crank up the bias current and make it run class A up to probably a pretty respectable wattage especially for these speakers considering you have enough heatsink for 160 watts per channel anyways. Though you might not get too much power before running into heatsink issues because of the voltage rails being optimized for class AB
@xrk,
Just go with your planned setup with lower cross and make ABX files. You will never be able to satisfy all weirdo's around the world🙄 Although there are a lot of people who will appreciate the effort
Peter
How about using the full range driver full range? Just put it in a large enough sealed box and call it good.
Well I am not exactly throwing around components on the XO, I design it in PCD first so most of it simulated before I construct it. Using the miniDSP as a pathfinder is a good idea though - at least I get a sense of what it "should sound like".
The amp indeed has a bias adjustment and it is running 80mA now per transistor. These guys can easily take 1 amp bias but my PSU can't handle that. I have run IRFP240/9240's at 175mA bias before but not sure if there is a benefit as the distortion is already low. I could also just switch to my class A amp - but not sure what going to class A buys me at this point?
Here is my class A amp - the inverted JFET Circlophone. It uses a servo feedback sliding bias to stay in class A, and quasi complimentary outputs for lower distortion. Produces a nice level of power with reduced heat relative to conventional constant current soure (CCS) class A amps that burn the same heat no matter if they play music or not. It does run quite a bit hotter than conventional class AB though with idle current around 250mA.
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This is actually a good idea - since I am testing just one driver brand and model, the TS parameters allow an optimized box. I actually have a foam core Lance TL for the FF85WK. It would probably work well in a simple sealed full range but there won't be any bass so it will sound thin.
@xrk,
Just go with your planned setup with lower cross and make ABX files. You will never be able to satisfy all weirdo's around the world🙄 Although there are a lot of people who will appreciate the effort
Peter
Haha, in the end, I guess I do what I please. 🙂
If we're now at the point of nominating some of our favorite demo tracks:
Duende - Bozzio Levin & Stevens
Loreena McKennitt - The Lady of Shalott / Beltane Fire Dance (Nights from the Alhambra)
Mussorgsky - The Great Gate of Kiev (mine from the Eiji Oie / Minnesota Orchestra / Reference Recording Tutti Orchestral Sampler)
>>> How about using the full range driver full range? Just put it in a large enough sealed box and call it good.
Since it's just the Fostex driver, building an optimal box and just swapping drivers might actually be better. It removes another variable (crossing the driver to the woofer).
If there's ever a future comparison test comparing the Fostex to other manufacturers then eliminating the variable of bass response (by using the same woofer) makes sense.
Since it's just the Fostex driver, building an optimal box and just swapping drivers might actually be better. It removes another variable (crossing the driver to the woofer).
If there's ever a future comparison test comparing the Fostex to other manufacturers then eliminating the variable of bass response (by using the same woofer) makes sense.
XRK has the full p10-hifi miniOnken planset that came with his FF85wKeN, and FH-Lite plans are at frugal-horn.com.
dave
Having a pair of the older FF85k drivers in micro-Fonken enclosures, I would say that the idea of running the drivers by themselves w/o XO is a very good idea. Just don't play tracks w/ lots of bass. You may be surprised at how nice they sound playing some jazz!
Cheers, Jim
Cheers, Jim
...And as a quiet word from the gallery here, I should point out, I have never at any time claimed Lance is 'optimal'. It achieves the specific design goals laid down for it, and a few people seem to like it, which is nice. I've never claimed any other cabinet I've ever done is optimal for that matter (unless in terms of a specific mathematical or acoustic alignment). They are what they are. I can live with that.
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X, I can offer line level passive (one cap, one resistor) for high pass at ~160Hz, with active 2nd order (ne5532) low pass in one box powered by batteries (2x9volt) as an alternative to mini dsp. Your choice of amps.
Thanks Planet10.
I did not realize a plan set was buried in the box somewhere. Not that I could make it out of wood (foam core might be fun). I will look more carefully inside. Are these plans not freely available from your website?
Thanks for the offer. Pehaps you can post the schematic for the active low pass? I might be able to make it quickly if it's an op amp or two with some caps and resistors. The passive line level XO is highly dependent on the amp's input impedance. Depending on which amp I use - that varies from 10k to 47k ohm I think.
We both live in metro DC area so getting it from you is no problem.
I emailed the link before i shipped the drivers. Not at home so i can't check my mail archives.
If you can't find it, email me and i'll give you the latest.
dave
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