[jonsk2514]

Do you remember what you used for a cutter when you made your circle cuts?

[Peter J]

I had similar lines in my circles due to making several passes to get through the full depth. Not sure if it’s an avoidable artifact of cutting the circles in MDF in more than one pass but a bit of sanding should fix it right up.

This ^^^

Clearances, deflection, runout in several mechanisms at work here will almost always produce results like this. The nature of the beast, I guess.  Best way to avoid is to cut in one pass, but it's purely a visual thing and has no effect on speaker performance.

[jonsk2514]

That is along the lines of what I was thinking. 

It has, however, increased my sanding effort, though... 
Although, surely not overly important on these pieces.

[jonsk2514]

I am going to back track a bit.  I had planned to post this about cutting the holes in the braces.  Now that we have been talking about it, I am reminded that I missed this. 

In reading the instructions for the Jasper hole cutting template, it said to use double stick tape on the back side to hold things in place.  This seemed to be a lot of effort and, potentially, a mess to clean up.  Also, I had those 2 - 10” braces that had a half circle cut from them.

For the 10” braces, I decided to clamp the two together and make the half circle cuts in one cut as a full circle cut in both pieces.



I cut just a “hair” less than the full thickness of the MDF:



The cutter just breaks through the underside of the piece. In doing it this way, the cut-out piece stays in place without the need for the double sided tape.  The cut-out pieces are then just popped out by had.  Any ragged edge is cleaned up when the edge rounding is performed.



For a holding fixture, I used 2 slide clamps, clamped to a sheet of plywood, to form sides that retained the piece I was cutting and later, performing the edge rounding on.  They also, form a nice stop that the ends of the piece being held.  The plywood underneath allows for the cutter to break through and not be damaged and gives something to clamp to.  This was just a piece of scrap I had.  A word of caution... the piece being held will slide a bit and the ends will be up against metal.  Take care to not run the router bit into the metal when routing towards the end of the piece.  I could have done better at protecting the ends, but....

[UtopiaNemo]

So is this design a bass reflex speaker? It appears to be. Is the standard design for the X-MTM a bass reflex design, or is it normally a transmission line, like the AV-3?

[jonsk2514]

So is this design a bass reflex speaker? It appears to be. Is the standard design for the X-MTM a bass reflex design, or is it normally a transmission line, like the AV-3?

This is a floor standing, ported speaker with 2 ports low in the back.   The cabinet for standard design X-MTM is the same as this, so it would be ported also.  The Encore version uses upgraded driver and crossover parts.

[UtopiaNemo]

Wait, the standard X-MTM is a floorstanding design, right? How do they differ from yours?

[Hobbsmeerkat]

The AV-3s use a pair of the smaller M-130 and GR3T drivers, & have a smaller front baffle/cabinet. I believe it is also a 4ohm speaker.

The X-SLS & X-MTM Encores use a similar overall design, but with the larger M-165 & Peerless tweeters, and is also an 8ohm speaker.

[UtopiaNemo]

The AV-3s use a pair of the smaller M-130 and GR3T drivers, & have a smaller front baffle/cabinet. I believe it is also a 4ohm speaker.

The X-SLS & X-MTM Encores use a similar overall design, but with the larger M-165 & Peerless tweeters, and is also an 8ohm speaker.

My question was more about the cabinet. The AV-3 is a transmission line design, but if the standard X-MTM floorstander is a like the OP’s, then it’s bass reflex....I believe. Is that correct?

[jonsk2514]

My question was more about the cabinet. The AV-3 is a transmission line design, but if the standard X-MTM floorstander is a like the OP’s, then it’s bass reflex....I believe. Is that correct?

The X-MTM and the X-MTM Encore that I am building are the same cabinet.  They both have 2 ports.  Sorry, I am not that up on the terms, so I am not sure if that is what you are calling “bass reflex”. However, they are different from the AV-3 in that respect.

[jonsk2514]

The X-MTM and the X-MTM Encore that I am building are the same cabinet.  They both have 2 ports.  Sorry, I am not that up on the terms, so I am not sure if that is what you are calling “bass reflex”. However, they are different from the AV-3 in that respect.

Based on Wikipedia (https://en.m.wikipedia.org/wiki/Bass_reflex), the X-MTM and the X-MTM Encore are classified as a “bass reflex” speaker.

[UtopiaNemo]

jonsk2514,Transmission line speakers have an exit point like a port, but the sound that comes out the back of the woofer(s) is directed through a winding path until it exits the cabinet. I’m not learned enough to know the details, other than true transmission line speakers tend to be more responsive in the lower octaves than a simple port(ie bass reflex), and they’re more complicated cabinet designs.

I’m pretty sure I read that the AV-3 is a TL design. It sounds like you answered my question though.

[jonsk2514]

jonsk2514,Transmission line speakers have an exit point like a port, but the sound that comes out the back of the woofer(s) is directed through a winding path until it exits the cabinet. I’m not learned enough to know the details, other than true transmission line speakers tend to be more responsive in the lower octaves than a simple port(ie bass reflex), and they’re more complicated cabinet designs.

I’m pretty sure I read that the AV-3 is a TL design. It sounds like you answered my question though.

Yes, that is a good description of the the AV-3.  The drawings for the AV-3 (http://gr-research.com/pdf/av3box.pdf) show a zigzag sound path from the drivers, up in the top, to an opening low in the cabinet and in the back.  The opening is just a rectangle cutout into the back panel.

All Danny’s designs appear to be a bit complicated given all of the internal bracing he includes.  The X-MTMs has 7 internal braces, which is the same as the AV-3s.  I would think the level of complication in building one vs the other is about the same.

In many of Danny’s upgrade videos, he talks about the lack of internal bracing in the commercial speakers.  I would think a commercial version of the X-MTM would not have the bracing that this one has, as that bracing is not looked at as being needed for sound reproduction, which is the function of the port.  Thus, without that bracing, what you say would be true about the ported speaker, it would be less complicated to build.

Are you looking to build a set of either the X-MTM or the AV-3s?  I would think the build effort is about the same.  The AV-3 is a bit smaller, if that makes a difference.  As for sound quality, I only know what I have read in this forum and gotten from video reviews.  That is, all of Danny’s designs are given high marks.  I would expect whichever of Danny’s designs you choose, you will be happy.

[UtopiaNemo]

Are you looking to build a set of either the X-MTM or the AV-3s?  I would think the build effort is about the same.  The AV-3 is a bit smaller, if that makes a difference.  As for sound quality, I only know what I have read in this forum and gotten from video reviews.  That is, all of Danny’s designs are given high marks.  I would expect whichever of Danny’s designs you choose, you will be happy.

I am looking to build a set of Danny’s designs, but I’m looking for a custom solution for my own setup(perhaps unnecessarily). I have cabinetry along the front of my room, including a waist-high wide counter that the LCRs sit on. Based on physical layout, the X-CS speakers would work best (the standmount version of the X-MTM). Encore versions, of course. 

However, I recently discovered that my front speakers sound a lot better crossed over at 50hz instead of 80hz. I believe the X-CS is designed for the standard 80hz HT crossover point, because Danny mentioned their -3db point is around 60hz. Anybody correct me if I’m misunderstanding rolloff curves here.

For this reason, I’m thinking of buying the X-MTM and building it upside down. This is an unconventional solution, but it would keep the drivers at the proper elevation, and also give me the lower extension to cross over to the sub at 50hz. I may have to keep the center channel as an X-CS, unless I discover that an X-MTM in can be built in such a way so as to keep the drivers in the center and the ports at the outside back of the enclosure without doing something weird to the sound.

Sorry to hijack your post; I’m really eager to read how yours turn out!

[hawkeyejw]

Do you remember what you used for a cutter when you made your circle cuts?

Either a 3 or 4 flute up spiral but, can’t recall which one. It’s a good quality bit and router, so I just assumed it was a part of the process as trying to go through the full .75” was causing the router to strain more than I liked.

FWIW nobody will know that line is there other than you, it’s behind the speaker! 

[jonsk2514]

Sorry to hijack your post; I’m really eager to read how yours turn out!

Not to worry...  I asked for it...   

I am looking to build a set of Danny’s designs, but I’m looking for a custom solution for my own setup(perhaps unnecessarily). I have cabinetry along the front of my room, including a waist-high wide counter that the LCRs sit on. Based on physical layout, the X-CS speakers would work best (the standmount version of the X-MTM). Encore versions, of course. 

However, I recently discovered that my front speakers sound a lot better crossed over at 50hz instead of 80hz. I believe the X-CS is designed for the standard 80hz HT crossover point, because Danny mentioned their -3db point is around 60hz. Anybody correct me if I’m misunderstanding rolloff curves here.

For this reason, I’m thinking of buying the X-MTM and building it upside down. This is an unconventional solution, but it would keep the drivers at the proper elevation, and also give me the lower extension to cross over to the sub at 50hz. I may have to keep the center channel as an X-CS, unless I discover that an X-MTM in can be built in such a way so as to keep the drivers in the center and the ports at the outside back of the enclosure without doing something weird to the sound.

Interesting dilemma.  I know that Danny has speaker designs that are not posted on his web page.  Maybe pose the question to him in an email.  I think, simply put, you are looking for a speaker about the size of the X-CS, but will drive down to 50hz, before the 3 dB roll off starts (or maybe just after it starts).  Maybe Danny can point you to a design that will do that.  Hopefully I summed that up correctly.

If someone else following this thread has a suggestion, I would not object to it being posted here.

[Danny Richie]

The -3db of the sealed box X-CS Encore is typically in the 60 to 70Hz range in room.

So the -6db down point (your crossover point) is about 10Hz lower.

So they will likely work just fine as is.

[jonsk2514]

I know, I know...  Got to get going on this project...

I have not been doing nothing ...  I ordered the components from Danny and received them the other day...

I got the upgrade with Sonicaps, Mills Resistors, 4 sheets of No Rez.  While it may not seem like it, I am excited to hear what this set of speakers sound like. 

I have been on another important project involving wood working and have put sone of my new skills to work.  Part of it has been gluing up pieces and I have used that to practice for gluing up the cabinets.  I know Peter really likes the Titebond I (the original), but I want to see what the Titebond III and the Quick and Thick would be good for.

My project has needs to be moisture resistant, which made it a good candidate for the Titebond III. 

The III says it is a slow set and it also says that the pieces need to be clamped together for 30 min minimum.  So a longer work time than the II or Quick and Thick.  I found that to be true.  I was able to reposition a piece after it moved while clamping.  It is moderately thick, but was still thin enough to spread nicely with the rubber glue brushes I have.  It is also thin enough to run when the piece is vertical, but it is a moderate “run” speed which seems like it would be a good candidate for using where glued surfaces will be vertical during assembly.  I didn’t compare it directly to the Titebond Original, so I can’t say for sure which would be better and for where.  Still, I think this glue is a good candidate for a lot of uses.

The rubber glue brushes work nicely to get a smooth/uniform layer of glue on the piece and it is easy to get the thickness correct for not having too much.

The Quick and Thick is just that and, as such, is not easy to “work” with.  And it sets up fast.  I had an oversized slot that I was fitting board into and thought that this glue would be a good candidate for this application.  Ugh...  This stuff does not spread easily with a brush.  Then, it is “quick” to setup.  I was off just slightly in fitting the board to the slot and, with just being hand-pressed together, I had to use a heavy rubber mallet to move the piece 1/16”.  Figure minutes (seconds?) before setup.  I see the use of this glue to be very limited.  Where on the speaker cabinet?  It seems that this glue would useful where precision is not important, a bead or 2 of glue will do and a hand press and hold would be sufficient.  I plan to use this glue for installing the internal braces and the quarter round rails, which should only need to be hand pressed into place.  The other place this glue might be good is for installing the diagonal braces that some of Danny’s cabinet designs use.  Maybe use a brad nailer to hold the diagonal brace in place while the glue cures. 

A note about the Titebond II.  I used this glue for installing the first set of quarter round rails.  I wanted something that was reasonably thick but would be spreadable and would setup quickly.  This glue worked for that purpose.  It is easy to brush and was just thick enough to not run when the quarter round pieces were turned over.  Then, when hand held in place for a minute or two, it was set enough such that the quarter round didn’t tend to move when using the brad nailer at a slight diagonal.  Not sure I would use this glue for much else, especially if repositioning might be required and there is a bit of assembly time required.

[pinkfloyd4ever]

Wow, I hate to say it, but reading this thread is confirmation that I definitely made the right decision in not trying to DIY my next pair of speakers. I can solder components to PCBs all day, wire up a power supply without too much smoke, and even build up a crossover without a PCB without too much trouble. And, with the help of my drill press, a file, and some cursing I can eventually get through the case work.

But, as I'm seeing in this thread, speakers are a whole different animal from electronics. All the woodworking skills and knowledge are way above my head, not to mention that I don't actually own any woodworking tools. 

My brother-in-law is quite the woodworker though, and has a well equipped wood shop in his garage. Maybe one day if this pandemic ever ends I can get him to help me with the woodworking part. Not sure we'd know where to start though, as neither of us have built speaker cabinets before, and there is clearly way more to it than the cabinet plans on the GR site have led me to believe.

Kudos to those of you with the tools and the skills though. It is interesting to read and see pictures about it. 

[diyman]

Wow, I hate to say it, but reading this thread is confirmation that I definitely made the right decision in not trying to DIY my next pair of speakers. I can solder components to PCBs all day, wire up a power supply without too much smoke, and even build up a crossover without a PCB without too much trouble. And, with the help of my drill press, a file, and some cursing I can eventually get through the case work.

But, as I'm seeing in this thread, speakers are a whole different animal from electronics. All the woodworking skills and knowledge are way above my head, not to mention that I don't actually own any woodworking tools. 

My brother-in-law is quite the woodworker though, and has a well equipped wood shop in his garage. Maybe one day if this pandemic ever ends I can get him to help me with the woodworking part. Not sure we'd know where to start though, as neither of us have built speaker cabinets before, and there is clearly way more to it than the cabinet plans on the GR site have led me to believe.

Kudos to those of you with the tools and the skills though. It is interesting to read and see pictures about it. 

Please don't be discouraged from building your own cabinets based on this thread.  I have been very critical of jonsk2514 from the beginning. While he acknowledges being an inexperienced woodworker, he nevertheless posts lots of detail about how he is building these cabinets with the expectation that it will help other people.   I think the reality is just the opposite.

He does things in very unconventional ways and doesn't seem to interested in how experienced woodworkers would go about doing those same things, easier, faster and more accurately.  As a result he appears to be struggling through what is actually a rather straight forward build.

So you confirm my fear from the beginning that rather than help other inexperienced woodworkers exactly the opposite would occur.  But if your brother-in-law is experienced with even a minimally equipped shop building speaker cabinets is no big deal. It's really quite easy if you know what you are doing and follow conventional methods rather than trying to invent new ones.