10F/8424 & RS225-8 FAST / WAW Ref Monitor

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#1,444
Absolutely, all the slopes one could wish for, as well as EQ bands, shelves and delays. The only thing it doesn't support is LT or other custom biquad filters like minidsp but I can live without that. Oh and linear phase filters but that's not my cup of tea either
 
#1,446
xrk971 said:
Dagger is polyfill or fiberglass as you suggest. Stuff it denser at the vertex and slowly tease it out loose and fluffy towards driver end and leave about 1in space without stuffing. Line the internal walls of the Dagger from the driver end for about 2in with 1/4in felt or melamine foam cleaning pads cut to about 10mm thick. This really helps prevent any back reflections on the driver and gives it a clean sound rivaling an open baffle.

For the larger main box, line at least 3 of the inside walls with egg crate acoustic foam pads, then add fiberglass or polyfill into the nooks and crannies around the Dagger, and in the main volume. I did not weigh it - but a good amount not too dense.

Optionally, line the outside of the Dagger with Noico mass loaded butyl rubber car door panel sound absorber. Also optionally line the inside of the main cabinet with Noico underneath the eggcrate foam. All of these little details will reduce the resonances and vibrations to really clean up the distortion from mechanical vibrations.

Don’t forget to put a round over in the baffle cutouts to allow the drivers to breathe.
Click to expand...

Noico butyl rubber means i think bitumen sheet. right?
 
#1,452
soundnovice said:
as far as xover goes, i have three options.
1. passiv xo
2. pllxo
3. raspberry pi dsp/piano dac

and i dont have experience with any of them!
i am guessing pllxo is will be a quick solution as the xover is 1st order with very few components.
Click to expand...

If you have no experience with any, the easiest is the DSP - although I am not familiar with how easy it is to implement in PianoDAC as that requires use of Texas Instruments graphical object and string connect interface. If you stick with RS225-8 and any of the tested 8 ohm full rangers (TC9FD, TG9FD, 10F/8424, FF85WK, PS95-8, you can use the passive crossover with mild tweaks to the attenuation (padding) resistor to suit your taste. It’s guaranteed to work.

PLLXO requires that you tune the XO match the input impedance of your preamp or input stage of power amp as they are an integral part of the crossover filter function. They may have different phase characteristics than the speaker XO.

If you use miniDSP brand - I know that works and is relatively easy. But my choice for best sound quality is the passive XO. Don’t change the woofer to SB23 though as that’s a totally different XO that has yet to be successfully designed. Aatto has tried but it seems that there are still issues and it may have to do with the differences in flatness across mid bass and breakup region. It will take a more complicated notch filter to make the SB23 work passively. But if DSP, not a problem.

Edit: I take back DSP is easier. The speaker level XO as posted is easy. It’s tested and requires simple soldering and guaranteed to work. Even miniDSP has a learning curve and investment is worth it but will take some time and costs more than passive XO parts ($80 total or $30 if you use 50uF bipolar electrolytic bypassed with cheap 10uF film cap). 60uF is close enough.

656203d1515700364-10f-8424-rs225-8-fast-ref-monitor-xrk971-10f-rs225-fast-schematic-jpg
 
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#1,453
#1,454
soundnovice said:
as far as xover goes, i have three options.
1. passiv xo
2. pllxo
3. raspberry pi dsp/piano dac

and i dont have experience with any of them!
i am guessing pllxo is will be a quick solution as the xover is 1st order with very few components.
Click to expand...

There's also the $20 "Linkwitz-Riley 2 Frequency division", which is an active line level XO found on Aliexpress. I've got 4 of them with XO frequencies from 80 to 500Hz for Sub-Satellite and WAW/FAST. Plan on waiting a month tho.
 
#1,455
hi XRK,
i had an audition of this speaker and it sounds very good. the builder said he has tuned the xover resistor and now fullrange is sounding even better, but i am yet to visit him again to listen. i understand that passive xover is a good solution at any time. however i am going to use the boxes to experiment and gain understanding about pllxo and dsp solutions also. probably i will eventually try all of them, but which one to start with is my question.
 
#1,456
tilroh said:
There's also the $20 "Linkwitz-Riley 2 Frequency division", which is an active line level XO found on Aliexpress. I've got 4 of them with XO frequencies from 80 to 500Hz for Sub-Satellite and WAW/FAST. Plan on waiting a month tho.
Click to expand...

Those look cool.

But if I get it right, you need to provide the XO point, and they'll fix it for you. It's not variable, and it doesn't account for driver impedance curves...
 
#1,457
perceval said:
Those look cool.

But if I get it right, you need to provide the XO point, and they'll fix it for you. It's not variable, and it doesn't account for driver impedance curves...
Click to expand...

Yes the XO point is set. The ALLXO outputs to amplifiers so I don't think driver impedance is an issue. In my Dayton/ScanSpeak system, the <500Hz output goes to a big old 50pc transistor amp powering the Daytons and above 500Hz goes to KT88 SET tube amp driving the ScanSpeaks. The SET's volume is turned up all the way. Bass is tweaked with the SS amp. DSP is done by FooBar2000 using the MathAudio plug-in.
I know it's not the best, but it's the easiest for time (and $) poor DIYers.
 
#1,458
soundnovice said:
hi XRK,
i had an audition of this speaker and it sounds very good. the builder said he has tuned the xover resistor and now fullrange is sounding even better, but i am yet to visit him again to listen. i understand that passive xover is a good solution at any time. however i am going to use the boxes to experiment and gain understanding about pllxo and dsp solutions also. probably i will eventually try all of them, but which one to start with is my question.
Click to expand...

You wouldn’t happen to live in India? I just got an email from someone in India who said they reduced the padding on the 10F XO and liked the sound better. It can be adjusted to taste of course. Sometimes with corner loading, bass can be overwhelming.
 
#1,460
New Build

My shorty-box passive FAST speakers are up and running. Kind of funny looking. No damping or absorptive materials installed yet, so sonic impressions are a little early. Widerange drivers are TC9FD, fitted into recess for a 10f/xxxx.

20181116_132023.jpg
(yes, image is sideways even after rotating and re-inserting, several times)

Ended up using plastic cones for the daggers for the speed and ease compared to constructing 3, 4, or 5-sided pyramids, Inside is the requisite stuffing and felt surround.

Boxes are 18mm BB, cut by a local wood and woodworking supply. Not great cutting, lots of tearout, and of course my dimensions were a bit strange.

Padding resistance is 2 paralleled 4.7Ohm resistors, and so far that seems about right for the TC9FD. Considering going to 10f/8414 eventually.

I'm hearing several impressive aspects so far - a notably neutral response, very nice persussion, low distortion, and an overall refined sound. One of my favorite loud rock tests is Dire Straits' "Ride Across the River." Good dynamics, clarity, and low distortion. Fun! Efficiency is very low, not too surprisingly.

Question for X: did you compare before and after cabinet treatment? I'll probably use Noico pads as you did, then acoustic foam in 2 or 3 phases.

Cam
 

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