I had been inspired by a design by Lukas Fikus aka Lampizator which was a 4-way using the open baffle and a ribbon top end, see Speaker Project 10 unfortunately when i last checked most of the pictures are missing — hope they come back soon! I built a single prototype having got hold of some classy ribbons, namely the Aurum Cantus G1. I found that speaker sounded amazing, but i used the bass in a 40L sealed enclosure if i remember correctly with the aim of applying Linkwitz equalisation. I never put the required effort to get the bass sorted out, and i felt the bass driver could offer more. In any case, i gradually gravitated to the idea of building a straight up ATC clone i.
|Published (Last):||11 October 2008|
|PDF File Size:||11.18 Mb|
|ePub File Size:||17.23 Mb|
|Price:||Free* [*Free Regsitration Required]|
I had been inspired by a design by Lukas Fikus aka Lampizator which was a 4-way using the open baffle and a ribbon top end, see Speaker Project 10 unfortunately when i last checked most of the pictures are missing — hope they come back soon! I built a single prototype having got hold of some classy ribbons, namely the Aurum Cantus G1.
I found that speaker sounded amazing, but i used the bass in a 40L sealed enclosure if i remember correctly with the aim of applying Linkwitz equalisation. I never put the required effort to get the bass sorted out, and i felt the bass driver could offer more. In any case, i gradually gravitated to the idea of building a straight up ATC clone i. But no way was i going to forego the ribbon tweeter! Never mind, i prefer to do it my way anyway. To cut a long story short, while more than viable especially using the Class-D amplifiers available, the added complexity to the project steered me away.
Total flexibility. The enclosure i comparable to the Wilslow Audio design, around cm high, Using 25mm MDF my calks gave an internal volume of around litres after deductions give or take. Running this though winISD gave a port length of 10cm using standard soil pipe mm external, mm internal diameter.
Quite short! Box lining is nothing fancy upholstery wadding gsm , but decent use of Monacor bituminous self adhesive pads was made MDM Having inspected ATC enclosures i have noticed they have a no nonsense approach. The tweeter has a passive high pass for essential protection with a ribbon at around 1KHz, so by 3. Future work will be to measure and equalise as necessary, but having tuned by ear its already a most enjoyable speaker — if you can find the space for it.
Here, as usual, i have put a large number of photos documenting the process. I hope it is useful to someone. I am most happy with the end result. These speakers kick butt, they sound how they look. The tweeter adds finesse missing from the commercial design.
Glueing up the main panels with rabbeted joints: Bracing for the cabinet, two per box and shaped to allow for the rear of the bass driver. Original plan was to put amps in the back hence why one brace has open space to the rear. There used to be full specs of all drivers on the ATC website, but since a recent website update that very useful file seems to have vanished i have it somewhere.
Anyway, the required data is still thankfully available on the Solen website : Front panels almost finished oversized, to be cut down and flush trimmmed later : Whoops! This stuff routes beautifully. Rebating the rear of the front panel to allow for the Mid done to come up flush with the front surface.
The horn on the ATC dome is actually around 19mm long so i had to take off something like 4 to 5mm from the rear to bring it flush as done on the commercial speaker very handy having those SCM50 front baffles hanging around : Snug fit, as intended: The Monacor self adhesive bituminous felt pads for panel damping.
A few staples give piece of mind: Panel lining with gsm upholstery wadding. Adhered using a standard upholstery adhesive in a spray can. Sticks very well: Glueing the front panels on: The protective passive high-pass filter for the ribbon tweeter. Second order with 13 mfd V cap and 1. Mounted to a small board, this allow the crossover to be removed it is attached using insert nuts and machine screws , should it need to be eliminated or changed at a later date removable through the bass driver cutout : Glued to the inside of the cab: Cutting the mm bass port pipe using a home made jig to keep things parallel enough : These circular cutouts are what hold the port to the inside of the cabinet, allowing the port surface to stay flush with the flared hole on the front baffle, if that makes sense: Like this, the ports inner surface is rebated: Hot glue works perfectly for this: And then glueing to the inside of the front baffle: Insert nuts inserted for the drivers tweeter and bass M4 for the tweeter.
Now the bass is apparently according to ATC suppose to use M6 bolts but i found the heads too big to sit inside the foam gasket that goes round the front of the driver. If anyone knows what that gasket is really for please let me know, because i have never seen this driver rear mounted and the foam is very hard and would make a terrible air seal anyway. I found M5 bolts much better and fit snug, but used washers to increase the surface area in contact with the driver. Last of the wadding applied: Glueing up the front baffles no going back: Onto the grilles.
I used 9mm MDF because most of it was being cut out anyway and i wanted the grille to be substantial enough not to vibrate. This is after three topcoats roller applied Dulux Satinwood in a subtle light grey. The weight of the cabinets is no joke and the MDF was not suitable for holding the M10 insert nuts.
I decided on a totally different approach which was far more satisfactory and robust: Speaker grille fixing inserted and hit home, flush with the front baffle: Test fitting the grille having inserted the fixings, fits perfectly.
It is thing acoustically transparent and good the work with, good stretch and number of colours available. I chose this light grey to contrast slightly with the cabinets: Some help from an expert seamstress: Castors removed i cut discs of rubber for the feet, I wanted a quality rubber with good grip, this stuff manufactured by SVIG is designed for the soles of shoes but has a low shore hardness of 50 so it has more grip than a usual sole.
It also cut well with the hole saw: Adhered to the underside of the cabinets. The corner protectors add a bit of style but also serve their function in protection the speaker corners during transit, The bottom edges are particularly vulnerable and i have seen commercial ATC speakers damaged on the corners in many photos.
They requires some work to create a quarter round cutout allowing the rubber feet to come close to the speaker edge, maximising speaker stability: The end look. Here you see the alternative mobility arrangement. Castors aren;t essential but boy, once you feel how heavy these speakers are you realise how convenient it would be to be able to wheel the around for vacuum cleaning etc.
Plinths of oak are used with castors fitted, speaker sits on top with rubber feet. This gives all options for the future i.
Midrange ATC SM75-150S
Zulkis Above frequency response measured at 0. Description Postage and payments. Distortion measured at 2. Have one to sell? An item that has been previously used. See all condition definitions — opens in a new window or tab.
I tried the Vifa 3" dome back then and never liked it much. Dynaudio had the D52 and mid-domes and used them extensively in their commercial products. Why they have gone out of fashion is a good question, maybe because 3-ways generally got out of fashion and thanks to D and other excellent dome tweeters, 2-ways took over although never able to deliver the same smooth transition between a 6" or an 8" midbass driver and the dome. Having a middome adds considerably to cost and crossover complexity. Today we see a couple of 2" and 3" domes from China and rather recently reintroduction of 3" domes from ScanSpeak. Maybe double laser interferometry could shed light on the issue, but until now it remains unsubstantiated claims.