New 3-way mid-top

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   So I’m getting closer to getting started on this build, thanks again for all of your help so far.
I have a couple more thoughts and questions before I begin to finalise my plans.

Due to the small room these speakers will be placed in I was wondering whether I may be better off with a wider dispersion horn, in order to avoid dead spots in the room and maximise coverage. The listening zone will be near field and I am concerned there may be a gap in the coverage when stood between the speakers, unless further back where the horns’ output meet as it were.

Obviously a wider dispersion will also result in more reflections however the room is quite well treated so I am slightly less worried about this.

So my question is whether there are any other drawbacks to choosing a 90 degree horn that I may not have considered? Such as getting the directionality of the 8’ to match that of the horn around the crossover point for example. Or just general sonic qualities etc.

I can’t seem to find any directivity plots of the 8’ driver anywhere online so am completely unsure of its specs in this regard. Would it be safe to assume anything based on the driver specs/data of the 8M400?

I have also been simulating using a Fane 12MB for the low mid unit, it seems to give a better low end response for the ~45 litre box volume. However I am not sure whether gaps in my knowledge are making me blind to it’s suitability for this build, are there any reasons that are obvious to you as to why it would not work well for this build?

Apologies for all of my questions, I am aware I have a lot to learn but am getting excited now to begin this build.

Many thanks

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UncleRay Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 25 October 2024 Status: Offline Points: 21	Post Options Post Reply Quote UncleRay Report Post Thanks(0) Quote Reply Posted: 15 November 2024 at 12:28pm
	So I’m getting closer to getting started on this build, thanks again for all of your help so far. I have a couple more thoughts and questions before I begin to finalise my plans. Due to the small room these speakers will be placed in I was wondering whether I may be better off with a wider dispersion horn, in order to avoid dead spots in the room and maximise coverage. The listening zone will be near field and I am concerned there may be a gap in the coverage when stood between the speakers, unless further back where the horns’ output meet as it were. Obviously a wider dispersion will also result in more reflections however the room is quite well treated so I am slightly less worried about this. So my question is whether there are any other drawbacks to choosing a 90 degree horn that I may not have considered? Such as getting the directionality of the 8’ to match that of the horn around the crossover point for example. Or just general sonic qualities etc. I can’t seem to find any directivity plots of the 8’ driver anywhere online so am completely unsure of its specs in this regard. Would it be safe to assume anything based on the driver specs/data of the 8M400? I have also been simulating using a Fane 12MB for the low mid unit, it seems to give a better low end response for the ~45 litre box volume. However I am not sure whether gaps in my knowledge are making me blind to it’s suitability for this build, are there any reasons that are obvious to you as to why it would not work well for this build? Apologies for all of my questions, I am aware I have a lot to learn but am getting excited now to begin this build. Many thanks

ceharden Members Profile Send Private Message Find Members Posts Add to Buddy List The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11851	Post Options Post Reply Quote ceharden Report Post Thanks(0) Quote Reply Posted: 15 November 2024 at 1:18pm
	Do you need coverage over a wide area? If not, just 'toe in' the speakers so that they are angled towards the centre of the room? This will also reduce how much goes onto the walls. The Fane Colossus 12MB was historically a very good driver, I don't know whether the modern production ones are as good but if it is, I see no reason why it would be a bad choice for the box. You can of course make the box larger if you need more volume to get a better low frequency response. If you leave the ports the same size, that will naturally reduce the tuning frequency.

fatfreddiescat Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 15 October 2010 Location: N.E.Wales Status: Offline Points: 1128	Post Options Post Reply Quote fatfreddiescat Report Post Thanks(0) Quote Reply Posted: 15 November 2024 at 6:06pm
	Listening to a 2 year old pair of 12MB's as I type, very nice, I have 8 in total from 2 batches of 4, approx 2 years apart and they all seem identical.

ceharden Members Profile Send Private Message Find Members Posts Add to Buddy List The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11851	Post Options Post Reply Quote ceharden Report Post Thanks(0) Quote Reply Posted: 15 November 2024 at 7:58pm
	This probably warrants a new post but I'm now working on another new design, this time a 2x10+1.4". Uses the same external panels as the 3-way 12+8+1.

JulianDA Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 29 May 2018 Location: Soest, Germany Status: Offline Points: 156	Post Options Post Reply Quote JulianDA Report Post Thanks(0) Quote Reply Posted: 15 November 2024 at 8:40pm
	Very nice craftmanship on both of these designs!

UncleRay Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 25 October 2024 Status: Offline Points: 21	Post Options Post Reply Quote UncleRay Report Post Thanks(0) Quote Reply Posted: 15 November 2024 at 8:43pm
	Top stuff! Love the look of this, especially the port design, it gives the speaker a very nice symmetry. How would you say it compares with the 12, 8, 1 design?

jeff generik Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 25 November 2006 Location: Dartmouth,Devon Status: Offline Points: 219	Post Options Post Reply Quote jeff generik Report Post Thanks(1) Quote Reply Posted: 15 November 2024 at 9:55pm
	Heard a few 2x 10 D’appolito pa tops before, they work very well! Yours looks great!

ceharden Members Profile Send Private Message Find Members Posts Add to Buddy List The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11851	Post Options Post Reply Quote ceharden Report Post Thanks(0) Quote Reply Posted: 16 November 2024 at 1:17am
	Too early to really know how it's going to perform, only got the first one loaded and started testing late afternoon. Pretty sure it'll be capable of going louder than the 1281, but I think the dedicated midrange and 1" compression driver means that one will always be more hi-fi. It's intended as more of a scalable design, I've used 16Ohm 10" drivers so that I can drive 2 or even 3 boxes off the same amp channels. Initial thoughts are it's got amazing transient response, probably mostly due to the light coned 10" drivers. Vocal presence is great (important because I mostly do live work) and the sound is very clean. There's a massive overlap in terms of frequency range between the 10" and 1.4" drivers so plenty of scope to play with the crossover frequency to see what works best.

ceharden Members Profile Send Private Message Find Members Posts Add to Buddy List The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11851	Post Options Post Reply Quote ceharden Report Post Thanks(0) Quote Reply Posted: 16 November 2024 at 1:20am
	I must admit that I didn't actually do the woodwork on this one. I did all the drawings and asked my CNC guy to assemble them as well.

Andylaser Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 16 April 2010 Location: Southampton Status: Offline Points: 392	Post Options Post Reply Quote Andylaser Report Post Thanks(0) Quote Reply Posted: 16 November 2024 at 3:24pm
	The double 10s look great. What size VC does the CD have?
	"music so loud, that if we move in next door to you; your lawn will die" - Lemmy

Xoc1 Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 485	Post Options Post Reply Quote Xoc1 Report Post Thanks(0) Quote Reply Posted: 16 November 2024 at 8:52pm
	I was interested to know what 10" drivers you used, Modern 10 mids seem to have a bit more x-max which allows a bit more bandwidth on the bottom end.

ceharden Members Profile Send Private Message Find Members Posts Add to Buddy List The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11851	Post Options Post Reply Quote ceharden Report Post Thanks(0) Quote Reply Posted: 17 November 2024 at 1:09am
	The 10" drivers are the new B&C 10MBX64. Not massive power handling but very high efficiency and being light coned, very fast with a great midrange. The compression driver currently is the 18Sound NSD1424BT as I had a couple left over from a project many years ago, they're a 2.5" diaphragm. They're quite expensive nowadays so I've got a couple of alternatives shortlisted which are slightly more cost effective if I want to have more than one pair of them.