In-wall speaker install.

[panteragstk]

You'd want to measure a single driver in half of that volume.

Well, the issue with that is I can't take this thing fully apart. I don't really have another way to do it.

Guess I shouldn't have built the cabinet...

 

[panteragstk]

@annunaki do you know of a way I can test the tweeter without taking the entire speaker apart? I've looked and haven't been able to find a way to remove the tweeter.

Will my hastily made cabinet not work at all?

 

[annunaki]

Honestly, you are not building a separate baffle and new crossover for this speaker. Don't worry about measuring the tweeter. While the mass method is not ideal, it may work here without risking tearing the speaker apart (see my solution below however). In addition, the performance difference in a sealed enclosure is pretty forgiving. Most sealed enclosures are not going to change in performance much with a variation of +/-10%.

Here is another solution for a test enclosure without tearing everything down. Test one woofer at a time in the baffle. Make sure they are NOT connected together electronically. Take a couple pieces of soft foam and wedge them gently, and evenly around the woofer between the basket, spider and cone of the opposite woofer that will NOT be tested. That way in the test enclosure ONLY ONE woofer can actually move. This will allow you to get a relatively accurate measurement of the one woofer at a time. Just be careful. All you want is for the cone not to move once in the test enclosure. Per TLS Guy's recommendation though build the enclosure at half size your original plan as you are only testing one woofer at a time.

 

[TheWarrior]

Well, the issue with that is I can't take this thing fully apart. I don't really have another way to do it.

Guess I shouldn't have built the cabinet...

You needed to build a box to test. You just didn't fully understand what you were doing when you built the box. Perhaps put it under a chop saw and cut in half that way, flipping it over if the box is larger than the blade.

 

[panteragstk]

You needed to build a box to test. You just didn't fully understand what you were doing when you built the box. Perhaps put it under a chop saw and cut in half that way, flipping it over if the box is larger than the blade.

You are correct, didn't understand. The smallest I can make it with the whole speaker being able to fit is 3.5" deep. Would that suffice?

 

[TheWarrior]

You are correct, didn't understand. The smallest I can make it with the whole speaker being able to fit is 3.5" deep. Would that suffice?

You stated before that they recommended just sealing a 2x4 above and below in the wall cavity. Determine what that volume would be, and build a box half that size to measure a single driver. Other factors include where you live as you may have fire blocks between your studs. That is nothing more than a 2x4 set perpendicular between two studs intended to suffocate a fire and keep it from rising.

Knowing their recommendation also means that by building a box, you are reducing the volume of the wall cavity by the displacement of the wood panel being used as the 'back' of the box. So that volume has to be made up for elsewhere.

Or just go with their recommendation and let your brain rest from over thinking this. Believe me, I do it all the time!

 

[panteragstk]

You stated before that they recommended just sealing a 2x4 above and below in the wall cavity. Determine what that volume would be, and build a box half that size to measure a single driver. Other factors include where you live as you may have fire blocks between your studs. That is nothing more than a 2x4 set perpendicular between two studs intended to suffocate a fire and keep it from rising.

Knowing their recommendation also means that by building a box, you are reducing the volume of the wall cavity by the displacement of the wood panel being used as the 'back' of the box. So that volume has to be made up for elsewhere.

Or just go with their recommendation and let your brain rest from over thinking this. Believe me, I do it all the time!

Well, this little box is close to what the volume of the cavity of drywall will be since it is about 4" deep, but 16" wide. It's close, but not perfect.

If anything it will at least give me a good idea of how it will sound. I'll still attempt to measure it and see if it provides any useful data.

 

[TheWarrior]

Well, this little box is close to what the volume of the cavity of drywall will be since it is about 4" deep, but 16" wide. It's close, but not perfect.

If anything it will at least give me a good idea of how it will sound. I'll still attempt to measure it and see if it provides any useful data.

As long as the box is only half as tall as needed, yes! A little bigger than actual was the suggestion, and 4"x16" is obviously bigger than actual.

For the actual, just make sure to measure the real distance between studs. 16" OC does not mean there is 16" between the studs. Just like a 2x4 stud is not 4 inches deep. Not to sound pretentious, those simple details are easily over looked!

 

[Pogre]

Well, this little box is close to what the volume of the cavity of drywall will be since it is about 4" deep, but 16" wide. It's close, but not perfect.

If anything it will at least give me a good idea of how it will sound. I'll still attempt to measure it and see if it provides any useful data.

Could you put a divider in the box you built and cut the volume in half that way? Might be easier than cutting it in half or building a new one.

 

[panteragstk]

As long as the box is only half as tall as needed, yes! A little bigger than actual was the suggestion, and 4"x16" is obviously bigger than actual.

For the actual, just make sure to measure the real distance between studs. 16" OC does not mean there is 16" between the studs. Just like a 2x4 stud is not 4 inches deep. Not to sound pretentious, those simple details are easily over looked!

Right. When these are installed there will be plenty of measuring before they are put in. I'm a measure 10x cut once, screw it up somehow, cut again kind of guy.

I build furniture so I can measure things properly as long as I'm paying attention.

 

[TheWarrior]

Right. When these are installed there will be plenty of measuring before they are put in. I'm a measure 10x cut once, screw it up somehow, cut again kind of guy.

I build furniture so I can measure things properly as long as I'm paying attention.

Been there, still doing that!

Heading back downstairs to keep working on an entertainment center I am building out of plywood drops that I have rejoined and cut to size. Yay recycling!

 

[panteragstk]

Ok. I put it in it's shabby little box (that took all of 5 seconds of listening to for me to know it was too large) and gave it a listen. That little speaker sounds surprisingly good. I don't think I've heard an in-wall sound that good (most of them suck so that's not saying much) but I'm happy so far.

I can tell you that just closing off the top and bottom of the wall cavity won't be sufficient. I'll have to close the sides as well. This is a solid little speaker, but it still only has dual 3" mids.

The big brother (seen in the pic to the right) would probably do fine in a top and bottom closed in wall cabinet, but I still want to try to model it so I can get exact cabinet size from those that know more than me.

 

[panteragstk]

@TLS Guy I'm not sure where to proceed here. I want to do this correctly and am somewhat stuck.

 

[TLS Guy]

@TLS Guy I'm not sure where to proceed here. I want to do this correctly and am somewhat stuck.

I'm not sure what you are stuck with.

You don't need a box to get the TL parameters, the added mass method works perfectly well. If that box in the picture is sealed you can still use that and measure the two drivers. You just divide Vas by 2 to get the single driver parameter.

 

[panteragstk]

I'm not sure what you are stuck with.

You don't need a box to get the TL parameters, the added mass method works perfectly well. If that box in the picture is sealed you can still use that and measure the two drivers. You just divide Vas by 2 to get the single driver parameter.

Thank you. The reason I was stuck is because I don't know how I'd use the added mass method for the tweeter.

If the box will work (it is sealed) then I can remove the drivers from the crossover and measure them individually. Would that work?

 

[TLS Guy]

Thank you. The reason I was stuck is because I don't know how I'd use the added mass method for the tweeter.

If the box will work (it is sealed) then I can remove the drivers from the crossover and measure them individually. Would that work?

I think you can measure them as they are. I don't think you need to worry about the crossover, the increase in resistance from the coils I don't think will make a significant difference.

You don't need to worry about the T/S parameters of the tweeter. You really only need Fs and Qts for the crossover design. You want the tweeter 18 and preferably 24 db down at Fs. You can drive a very low Qts tweeter down below Fs if it can handle the power.

 

[panteragstk]

I think you can measure them as they are. I don't think you need to worry about the crossover, the increase in resistance from the coils I don't think will make a significant difference.

You don't need to worry about the T/S parameters of the tweeter. You really only need Fs and Qts for the crossover design. You want the tweeter 18 and preferably 24 db down at Fs. You can drive a very low Qts tweeter down below Fs if it can handle the power.

Ok. Thank you. I'll give it a go when I get the time.