Hi All, i’m home demoing some ATC SCM40a next week vs my Ovator S400 & NAP200DR. The dealer is loaning me a Chord Shawline Din to XLR to drive the 40’s from my 272 however if I end up purchasing them i am not keen on spending circa £900 for the shawline in the 3m length Ill need, thus im going to have some made up, 4 pin Din pre out to 2x xlr.
While im at it im going to get a phono to 5 pin Din made up too, probably to be used for my TT pre in and so my query is which cable would be best suited for each, or both.
The 2947 is a twin 75ohm coaxial with a 59pf/m capacitance. The 3106 is a twin microphone cable with an overall shield and is used in many studio interconnects, capacitance is 77pf/m on the shield, 10pf/m between cores. The 3106 is also a higher csa and therefore lower conductor resistance.
Not sure if either the 4 pin Pre out to xlr or the phono to 5 pin Din input would benefit from one or the other, any advice please?
Hi @Dannywin42 . When I got my SCM40As and current streamer/DAC/pre the only discussion with the dealer regarding cables was “how long do you want them?” I opted for 8m. I think they came from ATC themselves and I wasn’t charged for them. My preamp has a fully balanced output so they’re not the correct cables for your setup, but as @Naim_The_Dragon suggested, you could do worse than ask ATC. They’re helpful people.
BTW have you read Jason Kennedy’s review of the combination you’ll be auditioning? Unless you have a very unhelpful room, I reckon you’re in for a treat, but then I’m biased!
Thanks I might try that, the only reason I went down the mogami route was from other forum posts recommending it and the cable builder I have discussed with has offered either 2947 or 3106. Also not sure if the ATC cable will be phono to xlr where as I would like din from recommendations on this forum.
Thanks, as I understand it though I’d need two runs of 2497 and I dont think that would fit into a 4 pin din as the OD is 4.8mm, hence the 2947 which is a twin mini coax (2x3mm) vs a normal coax as the 2497 is. I actually read your response to another forum post, I believe on the scm40a, where you recommended the 2947, that’s where I found the original idea from.
Any suggestions for the 5 pin to 2 phono cable? Again not sure of 75ohm makes any sense as an audio connection or whether the lower resistance of the 3106 would make any difference
It doesn’t limit connecting the sub, I do just that!
Connect each of the main speakers to a 4pin DIN out and connect the sub via the 2 RCA phonos.
In my case, I connect a miniDSP 2x4 to the phonos on the 272, and use that as a line driver to drive a longer phono lead to the sub. This takes the capacitative load of a long lead away from the output electronics of the 272. It also means that the DSP can be used for two filtering operations; firstly to get a more precise crossover between the main speakers and the sub, and secondly to reduce the effect of room resonance form the sub’s response.
If you are using ATC SCM40’s and you’re looking at a sub for a 2ch system, you must be lucky enough to have an absolutely enormous listening room: SCM40’s don’t lack for bass response or extension in any way at all!
Thanks for your input, very much appreciated. The sub certainly isn’t for increased output but rather for smoothing response. My room suffers a really rather troublesome 35hz peak of around 15db with my ovators, hoping the atc are less troublesome however the ultimate goal would be to have some kind of dsp/ active crossover between the 272 and both the atc and the sub to give me a nice flat response from 200hz down exactly as I have with my hc system but of obviously better quality. I haven’t found anything remotely suitable quality wise yet which will allow me to do this however I’ll see what the response of the 40’s are like in my room in comparison to the ovators.
I’ll get my rew measurements redone this week on the ovators before swapping them out with the 40s, I may even start a thread on it if it peaks people’s interest.
Hi, to quell the over-exuberance at 35Hz, you may do much better using SCM19a and a sub, with a notch filter at 35Hz, rather than using the SCM40s as the 40s have a fairly well extended lower response that is likely to excite the 35Hz resonance irrespective of the sub.
This is what I do (with Spendor SP2s - lower response -3dB at about 50Hz) in a similar room with a +21dB resonance at 38.5Hz. I also found that the room greatly benefited form a lot of pressure mode (i.e. sealed) acoustic absorption 30Hz to 350Hz. Although the difference between +15dB and +21dB means that you may not need such an extensive bass trap system as that which I use.
I tried using digital signal processing to control the signal to the main speakers, but I found that I lost other qualities from the sound by doing that; true, the difference wasn’t massive but it was still a degradation that I found unacceptable.
By leaving the signal to the main speakers unaltered (with their naturally limited lower frequency) filling the missing lower frequencies with the sub and filtering the input to the sub to control the problematic frequencies gave the best of both worlds. The signal to the main speakers was still clear and unaffected covering the frequencies where the ear / brain combination has best discrimination and is most critical, but still greatly reducing the most troublesome frequencies from the sub.
N.B. when integrating a sub, it’s wise to be aware of the phase relationships through the crossover. The amp and heavy driver in the sub cause a group delay in the sound from the sub (~4ms for my sub) and taking account of that delay, (e.g. by placing the sub closer to the listening position) you can get a much better integrated sound stage (the sub then doesn’t sound ‘detached’ from the rest of the music).
It was quite good, however, I’m not using either in my system now.
Over the last few months I’ve changed to a dCS Rossini and clock into an Ayre KXR 20 pre into ATC 50A active towers…all connected with XLR to XLR interconnects…superb. I still have my Naim Fraim though
I’m applying an educated guess as I haven’t tried it, but I believe you can use the impulse function in rew so long as you have a timing reference set, so you should see the impulse response from the speaker system as a whole at the crossover frequency set and if the phase is out for the sub you should see a second impulse on the result, it should then be a matter of either calculating the delay if using a dsp and feeding the relevant delay in or altering the subwoofer phase by trial and remeasure.
Yes I suspect I’ll end up not doing anything with regards to the 40a output, I cant imagine any dsp will give a good enough output, im hoping the 40s have better bass response overall than the ovators and then I’ll be able to live with the hump at 35hz. Unfortunately in my current room the ovators just sound empty in the bottom end apart from at 35hz. I’ll find out over the coming weekend anyway, exciting times