Hi everyone!
I'm about to take my first step into making a pair fo speakers myself. I am a pro audio engineer, and I need a pair of main monitors for my studio. I would love some comments on the build I am planning.
The box will be a dual bassreflex port 65L cabinet, with 2 x Volt B2500.1, ATC 75-150 Mid and the Scanspeak 9900 tweeter. The design is made and built by wilmslow, but adjusted to my wishes regarding drivers and sound. I expect they will deliver an excellent pair of speakers, and much more pro looking than I could ever do. I have ordered them with double bracing and a front baffle (in case I would want to try other drivers down the road.)
The speaker will be powered by 2 x Digmoda DDC552 which delivers 2 x 500w + 250w all in 4 ohm. The 2 Volt drivers in parallel will be 4ohms, and will have a full 500w/4ohm from the amp, the ATC mid should have 125w/16ohm, and the 9900 will have something like 200w/6ohm. Will this be problematic with the high impedance of the ATC mid? Of course I will no doubt have to attenuate the tweeter, but the 125watt for the mid should be more than plenty to go very loud I would assume?
Any thoughts/suggestions for this design? It will be used in a studio, so the number one concern is low distortion and linear response, and these drivers all seem to excel in that area.
Please comment, I would very much like to learn 🙂
Regards, Tor
I'm about to take my first step into making a pair fo speakers myself. I am a pro audio engineer, and I need a pair of main monitors for my studio. I would love some comments on the build I am planning.
The box will be a dual bassreflex port 65L cabinet, with 2 x Volt B2500.1, ATC 75-150 Mid and the Scanspeak 9900 tweeter. The design is made and built by wilmslow, but adjusted to my wishes regarding drivers and sound. I expect they will deliver an excellent pair of speakers, and much more pro looking than I could ever do. I have ordered them with double bracing and a front baffle (in case I would want to try other drivers down the road.)
The speaker will be powered by 2 x Digmoda DDC552 which delivers 2 x 500w + 250w all in 4 ohm. The 2 Volt drivers in parallel will be 4ohms, and will have a full 500w/4ohm from the amp, the ATC mid should have 125w/16ohm, and the 9900 will have something like 200w/6ohm. Will this be problematic with the high impedance of the ATC mid? Of course I will no doubt have to attenuate the tweeter, but the 125watt for the mid should be more than plenty to go very loud I would assume?
Any thoughts/suggestions for this design? It will be used in a studio, so the number one concern is low distortion and linear response, and these drivers all seem to excel in that area.
Please comment, I would very much like to learn 🙂
Regards, Tor
That looks like an awful lot of money to spend on a first attempt at DIY. Here is a similar project that did not go smoothly.
How are you handling the crossover and equalisation?
Is the speaker to be flush mounted, free standing out in the room or something else?
How are you handling the crossover and equalisation?
Is the speaker to be flush mounted, free standing out in the room or something else?
I will not be building anything myself, Wilmslow will take care of that, including cutout for amps 🙂 I will only be mounting the Digmoda DDC552 into the cabinet, and wiring it all up.
The Digmoda amp is an active DSP plate amplifier. So the crossover/EQ would be digital = trial and error is at no cost.
Free standing for now, maybe flush mounted later on.
The Digmoda amp is an active DSP plate amplifier. So the crossover/EQ would be digital = trial and error is at no cost.
Free standing for now, maybe flush mounted later on.
Looks like it will be a nice build. I'd like to see some pictures of that when it's done. I'm thinking it will be like the ATC SCM100 speakers with the baffle bolted to the front?
You're in safe hands with Wilmslow. It amazes me that they are willing to do such custom work without there being any charge over and above the price of one of their standard builds.
Stefan
You're in safe hands with Wilmslow. It amazes me that they are willing to do such custom work without there being any charge over and above the price of one of their standard builds.
Stefan
Yes, the look will pretty much be like the ATC SCM100 in walnut, with a black front baffle, but the driver layout will be like the Quested Q210. The crossover will probably be a variation of the standard ATC crossover, but I will have the advantage of being able to do some Time and Phase aligning in the DSP.
I love ATC's, I love PMC, and I love Questeds, but there are aspect of each that I don't like. This here seems like a way to incorporate the best of all worlds. I love the punch from the PMC speakers/Volt drivers, but I do not love the over exaggerated low end from the TL cabinets. There's something about it that makes the bottom end seems out of time on some material. And the DSP should give me a way of correcting the crossovers if they are ever flush mounted right?
I have read a few places, that Wilmslow have a habit of not bracing their speakers quite enough, so I have asked them to do double bracing. I would think that for a studio monitor, you would pretty much want a cabinet that is totally "dead"...?
I love ATC's, I love PMC, and I love Questeds, but there are aspect of each that I don't like. This here seems like a way to incorporate the best of all worlds. I love the punch from the PMC speakers/Volt drivers, but I do not love the over exaggerated low end from the TL cabinets. There's something about it that makes the bottom end seems out of time on some material. And the DSP should give me a way of correcting the crossovers if they are ever flush mounted right?
I have read a few places, that Wilmslow have a habit of not bracing their speakers quite enough, so I have asked them to do double bracing. I would think that for a studio monitor, you would pretty much want a cabinet that is totally "dead"...?
That is good so long as the hardware implements the DSP that is required. For example, some tweaks may want FIR filters but some DSP hardware only implements IIR filters. Some hardware does not have enough taps for the FIR filters. Some has the right hardware but inadequate software to allow it to be used in the way desired. I am not familiar with your particular DSP hardware and so it may well do all that is required but there is still potential for issues although obviously not on the scale of trying to get passive crossovers to work to a high standard.
Flush mounted the woofers are 94 dB sensitive into 4 ohms drawing 2 W with the ATC 91 dB sensitive into 16 ohms and drawing 0.5 W. So 500 W will give a peak SPL of about 118 dB for the woofers and 125 W will give a peak SPL for the midrange of about 115 dB. You might lose a few dB from the woofers free standing. I don't know the peak vs RMS capabilities of your amplifiers but things look in the right ballpark.
Bracing makes a cabinet stiffer and raises the frequency of the resonances but it does not reduce the amplitude of resonances. What reduces the amplitude of resonances is damping and getting effective amounts that into a cabinet can be a challenge.
I have to say I would not be wanting to splash that sort of money with a company that is currently up for sale and has a very patchy quality record over the last 10 years. I don't know who took over as designer after their last one parted company, but the lack of photos of any of their 'studio' range suggests these are paper designs waiting for a buyer.
As you cannot 'nip over' if there is anything wrong I hope my fears are unfounded and you get great speakers.
As you cannot 'nip over' if there is anything wrong I hope my fears are unfounded and you get great speakers.
Ok. This comes as quite the surprise for me. I have not read many bad things about wilmslow, and they have so far seemed to be super helpful and patient, advising on all the thoughts I have had on the speakers and drivers. I can't really see the design being much different with this kind of speaker configuration?
The lack of photos goes for pretty much every speaker on their site. The website is certainly not encouraging, so I have only based it on countless recommendations on various forums 🙂
The lack of photos goes for pretty much every speaker on their site. The website is certainly not encouraging, so I have only based it on countless recommendations on various forums 🙂
https://www.rightbiz.co.uk/buy_business/for_sale/122365_leicestershire.html
At that turn over they can't afford much in the way of design resource!
At that turn over they can't afford much in the way of design resource!
The DSP is only IIR filter, but has also Allpass filters to align phase. The FIR filters usually have a lot of latency/processing time from what I have read, and that is a bit of a problem when musicians need to play on top of a track, as that disturbs the timing. From what I have been able to find out IIR filters should be fine, but maybe not?
Cool. The amplifier is 2 x 500w and 1 x 250w in 4 ohms, continous I would assume, but I am looking into that. The amp modules are all icepower Class-D.
Ok, nice to know!
If you look at the thread I linked to earlier you will see that recent criticism concerns passive crossover design some of which is a bit baffling, mistakes in supplying what was ordered, supplying a faulty crossover and a degree of not keeping up with the evolution of speaker DIY.
In your case using DSP for the crossover removes a lot of the potential problem areas. The cabinet is likely to be basic but in line with the price being asked. It is likely to be a reasonable place to start but large cabinets that are acoustically dead require some design effort to get the damping to work effectively. The drivers are very expensive but seem to be the ones you want to use. I don't know the risk of their stopping trading after accepting your money but before delivery but if it is a concern for you then talk to them about how to address it. If the drivers require months of wait before delivery then this could be an issue that needs handling.
The Filters are all IIR filters. FIR filters seem to require quite a bit of time for processing, which means they will introduce latency. Not the best in a studio environment, where the musicians need to play on top of other tracks. It does have allpass filters for phase alignment, and everything else I could think of.
They are 2 x 500watt + 1 x 250watt amps. Amp modules are B&O icepower, and I am pretty sure that is the continous rating.
Good to know about the bracing 🙂
They are 2 x 500watt + 1 x 250watt amps. Amp modules are B&O icepower, and I am pretty sure that is the continous rating.
Good to know about the bracing 🙂
Yeah, I see the thread. I must admit, it seems partially like errors from wilmslow and largely like rookie mistakes on his part. There is a lot of signs of complete misunderstanding of procedures and instruments. Bad combo I would say 🙂
Though this is my first build, I do have an extensive background in audio theory and practice, and that is also the reason I want to do the crossovers stuff myself. The money is not an issue. If this setup works it will be 1/3 of similar specs from manufacturers. And then I could live with having to dampen the cabinets a little more myself 🙂
Wilmslow audio will not stop trading while you are making this purchase. The owners have no intention of stopping trading and are looking for a buyer so they can retire. They won't retire without one and this may take a while. Even if one is not found they'll wind down slowly.
I'll not say any more but take it as gospel that that is a true statement.
Stefan
I'll not say any more but take it as gospel that that is a true statement.
Stefan
But can you confirm any 'design' has gone into the cabinet. Or is is just a large box with some cutouts that may or may not work well with the chosen drivers?
Just to be clear I am a fan of what wilmslow do for DIY and used to pore over their catalogues in the pre-internet days. Just in the last 10 years they seem to have been struggling and the story is that they don't have the tech resources they used to have. But I have no corroboration for this, so may just be another internet rumour.
Just to be clear I am a fan of what wilmslow do for DIY and used to pore over their catalogues in the pre-internet days. Just in the last 10 years they seem to have been struggling and the story is that they don't have the tech resources they used to have. But I have no corroboration for this, so may just be another internet rumour.
I'm not worried about the project being finished at all. They have been super patient and helpful, so I feel safe in that regard.
For a speaker of this size and price I will by no means be buying anything I do not feel confident about. This will be a +4000£ project when finished, so I will not be satisfied with anything less than stellar. I should receive cabinet drawings in a few days, but they will surely be based somewhat on the SM210 on their website I would assume.
For a speaker of this size and price I will by no means be buying anything I do not feel confident about. This will be a +4000£ project when finished, so I will not be satisfied with anything less than stellar. I should receive cabinet drawings in a few days, but they will surely be based somewhat on the SM210 on their website I would assume.
well the same people are in charge now as have been for the last 20 years. They will be using the driver data to work out the box size needed like anyone else would. OK they are not using acoustic measurements of the drivers in an actual box calculate the crossovers, nor are they then remeasuring once a prototype crossover is built but then the aren't charging for this service either!
Seems Tannoy, KEF and B&W have thrown quite some R&D money at the problem and they all came up with a similar solution: Extensive bracing made from a different material than the cab and fixed using elastic 'glue'.
The bracing does distript the standing waves traveling along the inside surface of the cabinet a little it also narrows the Q of the resonance which makes it a little easier to deal with.
In charge yes. But designing? The way one of those models just replaces the ATC dome with a cone mid worries me. The OP is eyes wide open on this so I will butt out. But one last question. As the ATC 75-150s is not available other than in ATCs has anyone actually ever compared the 2 to see if the difference is noticeable?
Not many second hand SCM200s for sale to compare, but the one pair that is they want £27k for speakers and Amps!
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