I look forward to seeing what you find out. Have you considered placing your crossovers outside the box? I did this and it has advantages (ease of access and freedom from vibration), although you do end up with two more (fairly large!) boxes.
Unless someone can run the simulations for me on a PC it doesn't look like I will find out much!
David
David
I found an online calculator for the port dimensions and you can easily find Monacor T&S data. It might be that there exists online sim s/w which you could use for the filter characteristics too?
Hi all, I was massively lucky to buy these speakers from KatieandDad.
One speaker was more or less constructed but the other speaker had only the cabinet glued together - half the drivers were still in boxes.
I won't comment on his reasons for selling as he has made that clear, but he was a gentleman to deal with, and I am now incredibly fortunate to own a pair of speakers I thought I could never afford.
The first things I have been doing with these is fairly extensive cabinet modifications. They are massive boxes with no bracing at all and rang like a bell - particularly on the side panels.
I have therefore spent a lot of time over the last few days fitting oak batons - cross-bracing in all directions. I have fitted approximately 12 braces per speaker using the knuckle tests as a guide. Where I was unable to cross brace - mainly around the Volt woofer, I have fitted heavy gauge steel L-brackets to stiffen the panels as much as possible without adding too much mass.
I then used a combination of vinyl floor tiles and titebond melamine glue as recommended by Dr Geddes to provide some CLD damping, then on top of that is some bitumen/acoustic foam panels that came supplied with the kit. I then plan on lining them with a fairly dense layer of rock-wool - staying clear of the port and behind the woofer to minimise effects on port tuning.
Already the knuckle test is fairly 'dead' all over - a vast improvement on the stock speakers. I'm hoping the slight increase in 'apparent volume' caused by the added rock-wool will offset the extra bracing. However, it isn't too important as the volt data sheet states that there is reasonable tuning in volumes right down to 50L (standard cabinet is 70L).
I have already stripped the black painted veneer off one cabinet - which I know is a little sacrilegious, but the black ash look is a no-no in my house - so I have bought some walnut veneer to replace it with.
I plan on using sorbothane gaskets for the Volt mid-dome and Scanspeak tweeter (as used in my last three way active with measurable success), and will probably go active.
But first I would like to find out once and for all what is going on with the passive crossovers so I will be measuring them extensively once the speakers are built. I will be using REW and my UMIK-1 as I have used with previous projects - so I may have some answers for those interested in the passive crossover problems.
One speaker was more or less constructed but the other speaker had only the cabinet glued together - half the drivers were still in boxes.
I won't comment on his reasons for selling as he has made that clear, but he was a gentleman to deal with, and I am now incredibly fortunate to own a pair of speakers I thought I could never afford.
The first things I have been doing with these is fairly extensive cabinet modifications. They are massive boxes with no bracing at all and rang like a bell - particularly on the side panels.
I have therefore spent a lot of time over the last few days fitting oak batons - cross-bracing in all directions. I have fitted approximately 12 braces per speaker using the knuckle tests as a guide. Where I was unable to cross brace - mainly around the Volt woofer, I have fitted heavy gauge steel L-brackets to stiffen the panels as much as possible without adding too much mass.
I then used a combination of vinyl floor tiles and titebond melamine glue as recommended by Dr Geddes to provide some CLD damping, then on top of that is some bitumen/acoustic foam panels that came supplied with the kit. I then plan on lining them with a fairly dense layer of rock-wool - staying clear of the port and behind the woofer to minimise effects on port tuning.
Already the knuckle test is fairly 'dead' all over - a vast improvement on the stock speakers. I'm hoping the slight increase in 'apparent volume' caused by the added rock-wool will offset the extra bracing. However, it isn't too important as the volt data sheet states that there is reasonable tuning in volumes right down to 50L (standard cabinet is 70L).
I have already stripped the black painted veneer off one cabinet - which I know is a little sacrilegious, but the black ash look is a no-no in my house - so I have bought some walnut veneer to replace it with.
I plan on using sorbothane gaskets for the Volt mid-dome and Scanspeak tweeter (as used in my last three way active with measurable success), and will probably go active.
But first I would like to find out once and for all what is going on with the passive crossovers so I will be measuring them extensively once the speakers are built. I will be using REW and my UMIK-1 as I have used with previous projects - so I may have some answers for those interested in the passive crossover problems.
Please fill us in on what you do and how it goes! You were indeed very lucky to these! If you went active which crossover would you use?
I will take some pics tonight.
Crossover will entirely depend on measurements. My last active three way had fantastic flat overlaps at the crossover points - and therefore no frequency corrections were required at all - just straight forward electrical 4th order slopes, that resulted in good 4th order acoustic slopes!
But I suspect looking at the datasheets for these drivers, that they are going to need fairly steep crossovers and possibly some correction - looking at the break up of the volt woofer particularly - I think I may need digital active crossovers.
In which case I will be looking at either the MiniDSP 4x10HD or a pro-unit like xilica etc.
Crossover will entirely depend on measurements. My last active three way had fantastic flat overlaps at the crossover points - and therefore no frequency corrections were required at all - just straight forward electrical 4th order slopes, that resulted in good 4th order acoustic slopes!
But I suspect looking at the datasheets for these drivers, that they are going to need fairly steep crossovers and possibly some correction - looking at the break up of the volt woofer particularly - I think I may need digital active crossovers.
In which case I will be looking at either the MiniDSP 4x10HD or a pro-unit like xilica etc.
That will be interesting, I went for a cheapo Behringer CX3400 just as a stop-gap (and because I knew someone else who used one and it sounded OK) but I have not been able to decide which way to go after that. One thing complicating my setup is that I'm using balanced cables on XLR from preamp output onwards, and that narrows things down a bit. I'll look at Xilica. It's a pity you already stripped one of the cabs, I might have made an offer on those since I have the old-style ones.
Is not an issue on my set using the supplied acoustic pads. Also bear in mind my crossover is different. One reason I changed the tweeter was because I found the Scanspeak too aggressive /peaky as demod by WA. You got yourself a great bargain!
Delapoer - You will have 4th order electrical slopes then, which are almost certainly steeper that the passive crossover and therefore probably help reduce the out of band distortion for the close to crossover freq break -ups. The only issue is whether further freq response tinkering is required.
To be honest, after putting many man-hours, a lot of oak and glue into these cabs - I would have kept them anyway! I like the style of them, and they have a nice sloped baffle to help alignment of acoustic centres.
I think they would be impossible (certainly for me!) to contruct without CNC. But I would only contemplate using them after extensive modification.
Juancho - I agree- this is why I suspect some digital tinkering may be required!!
To be honest, after putting many man-hours, a lot of oak and glue into these cabs - I would have kept them anyway! I like the style of them, and they have a nice sloped baffle to help alignment of acoustic centres.
I think they would be impossible (certainly for me!) to contruct without CNC. But I would only contemplate using them after extensive modification.
Juancho - I agree- this is why I suspect some digital tinkering may be required!!
Which SS tweeter were they using, do you know? Also, what is different about your crossover? I believe that the pair from katieanddad were bought last year too.
It was called the 'Revelator' from memory. I will post my crossover circuit later but it doesn't have the extra cap in line with the mid. And Wilmslow stated that the mid should be connected out of phase compared to tweeter and bass.
Oh yeah, I have Revelators (2905/9900.00) they don't do anything to make a smooth sound, it's true, I think they are exactly what their name implies. The cap in the mid, I remember now, did you take it out, or were they supplied that way?
The Prestige use the Volt VM752 mid dome and the Ring Revelator R2904/70000.
The Ring Revelator has the spike like dome not like the 9900 revelator.
Note that the Volt VM752 mid dome has a high Fs compare to the ATC Mid dome. The Volt VM752 should be crossed slightly higher than the ATC mid dome. Using the DATS 2, my Volt VM752 measured at Fs of 413 Hz.
The Ring Revelator has the spike like dome not like the 9900 revelator.
Note that the Volt VM752 mid dome has a high Fs compare to the ATC Mid dome. The Volt VM752 should be crossed slightly higher than the ATC mid dome. Using the DATS 2, my Volt VM752 measured at Fs of 413 Hz.
It seems to have changed now but the Prestige akltam is referring to was known as the Prestige Platinum. The Gold and Silver Prestige had ATC mids and different HF drivers. These differences make it even stranger that WA are selling one type of crossover!
Just in case it might be of interest:
I bought my Prestige's from WA around 5 years ago . They were the old style cabinet ( i.e.rectangular box with a sloped baffle and 2 ports 6x13 cm 70 lt net volume, not the present Avalon clone)
Drivers are : Volt 3143 , ATC 150 16ohm, SS Revelator 99000.
Crossover was as follows:
Low pass on Volt : 3.0 mH in series; 120uF+1,5 R in parallel 12 dB/octave
Band pass on ATC : Series: 4.7 R +20uF +0.9mH + 100uF (!)
Parallel:1.8 mH+1.2R; 6.8uF+1.2 R ; 10R
High pass on Revelator: Series : 1,0 R+4.7uF+ 6.8 uF
Parallel: 0,18mH 18 dB/octave.
Capacitors were Supersound polypropilene ; inductors no brand air core; resistors ceramic 10Watts. All drivers connected in phase.
I have moved the crossovers outside and replaced all capacitors with Mundorf Supreme and resistors with Mundorf Supreme 20 watts. I have also changed the crossover on the Volt to 18 dB/octave by adding a second 1.8 mH inductor in series and removed the infamous 100 uF capacitor on the ATC. All drivers are connected in phase.
To me and to my friends ( all very seasoned audiophiles ) they sound excellent.
I bought my Prestige's from WA around 5 years ago . They were the old style cabinet ( i.e.rectangular box with a sloped baffle and 2 ports 6x13 cm 70 lt net volume, not the present Avalon clone)
Drivers are : Volt 3143 , ATC 150 16ohm, SS Revelator 99000.
Crossover was as follows:
Low pass on Volt : 3.0 mH in series; 120uF+1,5 R in parallel 12 dB/octave
Band pass on ATC : Series: 4.7 R +20uF +0.9mH + 100uF (!)
Parallel:1.8 mH+1.2R; 6.8uF+1.2 R ; 10R
High pass on Revelator: Series : 1,0 R+4.7uF+ 6.8 uF
Parallel: 0,18mH 18 dB/octave.
Capacitors were Supersound polypropilene ; inductors no brand air core; resistors ceramic 10Watts. All drivers connected in phase.
I have moved the crossovers outside and replaced all capacitors with Mundorf Supreme and resistors with Mundorf Supreme 20 watts. I have also changed the crossover on the Volt to 18 dB/octave by adding a second 1.8 mH inductor in series and removed the infamous 100 uF capacitor on the ATC. All drivers are connected in phase.
To me and to my friends ( all very seasoned audiophiles ) they sound excellent.
Please see post 306, 330, 453.
I use the following drivers:
Tweeter : Scan Beryllium Revelator
Mid range : Volt VM752
Bass : Twin Scan 25w/8565
The cabinet was custom made. I have this setup since July last year.
I am using self made pre-amp with electronic crossover as 12db.
Please see akltam.8m.com for more detail of my electronic crossover unit.
I found that my speaker still need more run-in. For my latest setup, the mid range was crossed at around 700Hz and 3000 Hz.
The mid range is way too forward and I have to pad it down by 1-2 db. The same for the Tweeter. I just use a single resistor like 1-2 ohms to pad down the tweeter and the mid range.
For the bass, it was a seal boxed design with internal volume close to 100 Litre. But I found that it may be too small for a twin 25w/8565. I tested that the FS of the whole bass box (twin bass with the box) has an FS of 48 Hz. So the box won't go below that which I am a bit disappointed.
The whole setup is very revealing. Treble and mid range is crystal clear. Bass can be very strong but not too deep. It may be too crystal for someone else taste. This is unlike what Katieandad experienced about the mid range. So I wonder if the passive crossover is wired properly or maybe something wrong with the design.
I use the following drivers:
Tweeter : Scan Beryllium Revelator
Mid range : Volt VM752
Bass : Twin Scan 25w/8565
The cabinet was custom made. I have this setup since July last year.
I am using self made pre-amp with electronic crossover as 12db.
Please see akltam.8m.com for more detail of my electronic crossover unit.
I found that my speaker still need more run-in. For my latest setup, the mid range was crossed at around 700Hz and 3000 Hz.
The mid range is way too forward and I have to pad it down by 1-2 db. The same for the Tweeter. I just use a single resistor like 1-2 ohms to pad down the tweeter and the mid range.
For the bass, it was a seal boxed design with internal volume close to 100 Litre. But I found that it may be too small for a twin 25w/8565. I tested that the FS of the whole bass box (twin bass with the box) has an FS of 48 Hz. So the box won't go below that which I am a bit disappointed.
The whole setup is very revealing. Treble and mid range is crystal clear. Bass can be very strong but not too deep. It may be too crystal for someone else taste. This is unlike what Katieandad experienced about the mid range. So I wonder if the passive crossover is wired properly or maybe something wrong with the design.
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