Soffit mounted 15" Tannoy Dual concentric project

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It applies to sealed boxes as well.
A small box increases the Q more than a big box.
One Qbox is higher than 0.7 (Butterworth) the speaker has a "hump" in the LF part of the frequency response.
Then we have the reinforcement coming from room loading. That can make the hump even higher, for worse one note reproduction.
 
Over-enthusiatic baffle step correction can have a similar effect.

Personally I have never needed it, on the contrary really.
My current woofers are 3dB less efficient than my Tannoys but I still have to knock off a further 5dB to get the overall response flat in room. Had I gone with the official 6dB of BSC my bass would be a full 14dB too loud.
Sure, in an open field or an anechoic chamber they'd likely be sounding a bit bass-light. But why should I make them to measure flat in situations they will never find themselves in when I can make them to measure flat where I am actually using them?
 
I changed mixing rooms about 4 years ago. The small ported speakers I used in my small, albeit very treated room sounded terrible in the new room. All of a sudden I could clearly hear the LF hump that they had. OTOH, the larger sealed cabinets I was using sounded much better, and using a sub became much easier.

I still have some treatment to do before the room is done. I might want to consider finishing it, and getting some good measurements once it is in there. Right now at 36% from the front wall I don't have any major issues, though it is a tad heavy around 200 or so. As you move around the room you obviously hear some bass peaks and valleys. Still, it's much better than any small rectangular room I have ever been forced to work in.
 
It is almost impossible to avoid all room nodes.
But some good bass traps go a long way!

At least the Tannoys have well controlled treble dispersion.
A friend of mine works in a studio which uses Dynaudio monitors and the wide dispersion of those domes can be a nightmare. At one point all their panning was off. They even suspected that the console was faulty but in the end all it was was a carelessly placed plastic folder to the right of the right hand speaker causing non-symetrical reflections.

PS: Remember to ensure that your listening position(s) are about 15deg off the Tannoys central axis. You may not need any toe in. Best to find the correct position for your speakers before you build a wall around them!
 
PS: Remember to ensure that your listening position(s) are about 15deg off the Tannoys central axis. You may not need any toe in. Best to find the correct position for your speakers before you build a wall around them!

The job of building the soffit is a whole other project really. Normally, you would want all the angles of the listening triangle to be 60 degrees, with the speakers angled in about 12-20 degrees (my 0300s are at 30 to conform to the dolby surround circle). Due to the way some rooms are constructed, sometimes you will see monitors at the 90 degree angle, which is not necessary, or wanted here. What I have to figure out is how much I care about the mix position, vs the client position/couch spot. I'm not planning on using these for my daytime mixing. The delay inherent in the digital crossover is going to put the signal out of sync with my video anyway. These are going to be my fun speakers, and it might be better for my mental health if I do most of my listening to them on the couch. As for the 15 degree off axis, that's how almost all guys have their monitors set up. You never see them turned directly on axis to the engineer. Chris Pelonis did a great thing when he made his model 42 dual concentric speakers where he made the shape of the small cabinets rhomboid which determines the axis to the listener when the back of the speaker is parallel to the rear wall. Very smart.

I can relate to your friends issue with the folder. Sometimes I'll be inundated with producer notes. I used to print them out until I could hear that paper all over my console made things sound smeared, and tiring. It never ceases to amaze me how much better things sound when I clean up! I'm sure part of that is mental, but I know a big part of that is symmetry of reflective surfaces around you in the mix position.

Getting excited to start building!
 
A question probably more suited for the flat packers among the planet 10 enthusiasts: If I want to assemble without clamps, is it possible to use trim screws along with wood glue for assembling the cabinet. Since it will be soffit mounted I will not see the sides or rear, and if I ever wanted to sell them in the cabinet for some strange reason I would certainly have the cabinets veneered.

Any issues with, say, trim screws to bund the parts together while the glue does its thing?
 
Screws as clamps were how i always did it... you will need to use pilot holes so having 2 drills is a necessity.

dave

Is that screws as well as clamps, or screws as clamps? I always drill pilot holes, I've got an excellent reversible tip setup for that.

It should be noted the wood Dave and his crew used is beautiful stuff. I was going to veneer the fronts, but I'm thinking of simply staining them the wood is so nice.

Thanks Dave:):up:
 
Well, my intern and I got the cabinets assembled today. I glued, and mostly used my trim nailer. I screwed some, but not as much as I thought I would.

I'm either going to veneer, or stain the fronts with a charcoal color stain.

I'm very happy with how these are coming out. A question for Dave: The driver does not touch the back brace, should it, and if so, what material should be between the driver and the brace?
 

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And how did they sound when you finished them?

Not good. No matter what I did with the crossover I couldn't get the honk out of them. I'm not sure how to proceed. I now have a pair of B&W 808s in here that clients LOVE. They also have a bit of honk, but I have them amped up nice and I enjoy them for what they do best: reveal what's happening under 50hz.

Not sure what to do with the Tannoys. The cabinets that were made for them are not really anything anyone would want to look at. I might end up selling just the drivers.
 
Not good. No matter what I did with the crossover I couldn't get the honk out of them.

FWIW, music 'honk' is in the ~440-880 Hz octave, so a broadband dip in the response is called for and if a horn, then historically the XO is shifted well above the norm to mostly roll off its max gain BW that causes throat distortion.

Not having any 'hands on' experience with the Tannoy, about all I can suggest beyond using frequency shaping EQ would be to experiment with damping in the throat or suspending some form of acoustical phase plug in front of it, both of which I've had good luck with for taming 'honking' horns and whizzer equipped 'FR' drivers respectively.

GM
 
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