New DIY MTM Towers designed by Dennis Murphy and Paul Kittinger

[jinjuku]

I will use spell check from this point forward (unless I'm in a hurry)

I'm going to roll with the 2.75" ID port for now. Don't won't to risk hosing up the veneer/ finish, etc. I did a sim in WinISD just to try and get an idea how much to reduce the length by. Had to tune the cabinet to 57hz to get the port length to 2.75. I'm sure that's off the mark. The whole funky TL thing changes things I'm sure. Anyway, looks like the length of the port with no flare goes from 2.75" to 2.14" (about 78%of the original length). Applying the same guesstimate to the flared port I go from 3.75" to 2.92"

Hopefully no port noise. Only 1/4" smaller The port is on the rear as well. Anyway, I hope to finish them (except for the spikes) this weekend-
JG

You should be able to recover from this:

Route out a disc of MDF 1/16" smaller than the current hole. get a piece of scrap mdf 2" wide by 6" length X 2 pieces and some rubber bands.

hang some rubber bands on a 2X6 and apply glue. Insert through the hole and pull flat against the inside of the cabinet. Using the rubber bands insert the other 2X6 and tighten up.

Let the glue cure for 24 hours +. Next mark a cross hatch over the opening to get your center on the glued in piece. Drill a hole (for the circle jig).

Drill a hole for the circle jig (you are using a router and jig right?) in the disc.

Apply glue. Line up the hole with the disc with the hole in the glued 2X6. Let if set over night. Route your correct hole. Saw through the remainder of the glued 2X6 and mount the correct port.

 

[Jeff G]

Done!! jinJuku, thanks for the thoughtful post re modifying the port opening. Couldn't do it. Too close to being done. It is only 1/4" narrower than the recommended port. I can still go back and change if it doesn't satisfy. So nice to have them up in the room of sound. I'll post about the sound after they break in a bit.
So far so good.
JG

 

[jinjuku]

Done!! jinJuku, thanks for the thoughtful post re modifying the port opening. Couldn't do it. Too close to being done. It is only 1/4" narrower than the recommended port. I can still go back and change if it doesn't satisfy. So nice to have them up in the room of sound. I'll post about the sound after they break in a bit.
So far so good.
JG

You cold also get a drum sander for the drill and just keep rounding it out to dimension.

 

[Ed H]

Curious. Has anyone heard any rumors about the status of the matching center channel? With a front baffle height <11", I hope!

 

[dkane360]

Curious. Has anyone heard any rumors about the status of the matching center channel? With a front baffle height <11", I hope!

Can't say that I have, although I've heard something about a bookshelf version

 

[Swerd]

Curious. Has anyone heard any rumors about the status of the matching center channel? With a front baffle height <11", I hope!

To flush mount the ER18 woofer you need a diameter of a little under 7". I would guess a front baffle 9" tall would work for a sideways MTM type center channel speaker, with an internal volume of roughly 1 ft³ for a ported cabinet. I'll have to work out the numbers before I know the dimensions for sure.

 

[Ed H]

Pardon the relatively stupid question, but would the XO require significant rework? I'm asking because I took special notice of the fact this TL design is more forgiving to speaker placement regarding rear / side walls. I'm sure rework is required, just curious how significant it would be, in theory of course. Thanks.

 

[TLS Guy]

Pardon the relatively stupid question, but would the XO require significant rework? I'm asking because I took special notice of the fact this TL design is more forgiving to speaker placement regarding rear / side walls. I'm sure rework is required, just curious how significant it would be, in theory of course. Thanks.

I have absolutely no clue what question you are asking.

 

[Swerd]

Pardon the relatively stupid question, but would the XO require significant rework? I'm asking because I took special notice of the fact this TL design is more forgiving to speaker placement regarding rear / side walls. I'm sure rework is required, just curious how significant it would be, in theory of course. Thanks.

This is about a center channel speaker using the same ER18 woofer and Fountek ribbon tweeter as in the floorstanding version with the MLTL cabinet that skyline_123 built. It will contain two woofers and one tweeter in the usual sideways MTM arrangement. In a standard port-vented cabinet, it will likely be about 9" high.

And yes, it will require a different crossover. To do that requires building a suitable cabinet. With drivers mounted, it can be used to design the crossover.

dkane360 mentioned a bookshelf version, one ER18 woofer and one Fountek ribbon tweeter in a 0.5 ft³ port vented cabinet. A design for this is in progress and will be available later this summer. These can be used as very good speakers by themselves, or as rear channel speakers in a multi-channel system.

 

[David LR]

I'll post about the sound after they break in a bit.
So far so good.
JG

Just joined the forum, first post. Probably not a good thing to whine, wheedle & plead right off the bat, but, here I go.

OK, I have been patient, I've been patient for 20 days, been looking everyday to see your updated sound review, but, sad to say, still left hanging. So, I joined this forum to see if I could prompt a response from you Jeff.
Inquiring & nosy minds want to know. These speakers are on my short list of
candidates for my next build. So, if you have the time, please be kind, let us know your listening impressions so far. Doesn't seem like you can lose with a Dennis Murphy crossover & Paul Kittinger TL, but always like to get as much info I can.

Thanks very much,

David

 

[BoredSysAdmin]

Just joined the forum, first post. Probably not a good thing to whine, wheedle & plead right off the bat, but, here I go.

OK, I have been patient, I've been patient for 20 days, been looking everyday to see your updated sound review, but, sad to say, still left hanging. So, I joined this forum to see if I could prompt a response from you Jeff.
Inquiring & nosy minds want to know. These speakers are on my short list of
candidates for my next build. So, if you have the time, please be kind, let us know your listening impressions so far. Doesn't seem like you can lose with a Dennis Murphy crossover & Paul Kittinger TL, but always like to get as much info I can.

Thanks very much,

David

http://forums.audioholics.com/forums/showpost.php?p=786543&postcount=95

 

[David LR]

Right, thank you, Skyline was the first person to build these speakers. I've read his review many times. Was hoping to get a response from Jeff G on his build. Just looking for another point of view.

David

 

[skyline_123]

Can't say that I have, although I've heard something about a bookshelf version

John Krutke from Zaph Audio has a bookshelf speaker that uses the same wonderful ER18RNX but a different Seas tweeter, the 27TDFC. He calls them the SR17's. If you're just bursting at the seams to build a bookshelf speaker with this woofer, I'm sure this is a nice alternative. Madisound sells the kit for $319 which includes parts only and $630 for parts and cabs.

Right, thank you, Skyline was the first person to build these speakers. I've read his review many times. Was hoping to get a response from Jeff G on his build. Just looking for another point of view.

David

To be honest, I'm anxiously awaiting a response too. If he's anything like me, he'd rather be listening to them than writing a review on them .

 

[David LR]

Skyline -

Well then, maybe I can get some additional info from you, if you don't mind.

After living with these speakers for some time, do you have any further comments on the sound quality ? Anything that you don't like at all ? I'm particularly interested in how violins sound at louder volumes. I listen to a lot of orchestral music, have yet to hear ( in my admittedly limited experience) speakers that aren't screechy or harsh with violins more often than not. Some of it probably has to do with my early 90's equipment.

Also, in your speaker search, what other designs did you consider ?? I myself would be interested in the Mini-statements by Curt C. except for the requirement to be 17 or so inches from the wall.

Anyway, if you have any further thoughts, I'd appreciate it.

Thanks,

David

 

[Swerd]

After living with these speakers for some time, do you have any further comments on the sound quality? Anything that you don't like at all? I'm particularly interested in how violins sound at louder volumes. I listen to a lot of orchestral music, have yet to hear ( in my admittedly limited experience) speakers that aren't screechy or harsh with violins more often than not. Some of it probably has to do with my early 90's equipment.

David

I'm not skyline, but I have heard the design prototype of these speakers, and I believe they might make you happy.

Dennis Murphy is a violinist who has played and/or performed for most of his life. He listens primarily to orchestral music and always makes his speaker designs perform as close as possible to his own perceptions of live orchestral music. I'm guessing that not only is he aware of the problem you describe, but his speaker and crossovers have solved it better than most others.

Where are you located, and how far are you from Maryland? If possible, you should pay a visit to Dennis and hear his various designs for yourself.

 

[David LR]

Swerd-

Thanks for responding. Well, if I lived in Hawaii, I could be farther away. I live in Oregon however, so, just about the same thing ! Would l love to hear them.

Also under consideration is MTM design vs. a three way. As I understand it, in a three way, the mid-driver is relieved of bass duties, thereby allowing a cleaner, more distortion free midrange, & giving deeper bass at the same time, depending on the woofer of course. There's a designer on the PE board, Maynard, who seems to be on a roll lately with well executed & received designs.

He has a three way with an OW1 tweet, CA18RLY midrange, Usher 8955A woofer, all top notch drivers. Considering this one also.

I don't build multiple sets of speakers per year like a lot of guys, not enough of money or time, so trying to maximize my dollars. I've got about $800 set aside for drivers & crossover. Like to get as close to reference level as I could, while still getting speakers that are forgiving of 500-700 receivers.

Anyway, on with the research. Appreciate your input.

By the way, Maynard has a high regard for Dennis Murphy. He remarked one time, after hearing a Murphy design, "Why don't I just give up & build one of his speakers, I'd be happy for the rest of my life" or something close to that.

So many good designs, hard to choose.

Thanks,

David

 

[Swerd]

Also under consideration is MTM design vs. a three way. As I understand it, in a three way, the mid-driver is relieved of bass duties, thereby allowing a cleaner, more distortion free midrange, & giving deeper bass at the same time, depending on the woofer of course. There's a designer on the PE board, Maynard, who seems to be on a roll lately with well executed & received designs.

He has a three way with an OW1 tweet, CA18RLY midrange, Usher 8955A woofer, all top notch drivers. Considering this one also.

Those are certainly good drivers, it seems like it would be good. I like the ER18 MTM design better than any 3-way I've heard, including Dennis's MBOW1 3-way, because it goes nearly as deep, and can be easily driven by any HT receiver.

By the way, Maynard has a high regard for Dennis Murphy. He remarked one time, after hearing a Murphy design, "Why don't I just give up & build one of his speakers, I'd be happy for the rest of my life" or something close to that.

That describes me perfectly . I once considered buying all the design gear and learning how to use it, and then I got to know Dennis. End of story.

 

[Tomorrow]

Swerd-

Thanks for responding. Well, if I lived in Hawaii, I could be farther away. I live in Oregon however, so, just about the same thing ! Would l love to hear them.

Interesting timing, this. David, my audio partner (AverageJoe) and I were just stroking our chins over the possibilities of our next Great Northwest GTG (held in Lincoln City). IF we do one...it just may be involving DIY projects from around the NW (or the country). Would you be interested in participating? Dennis and Swerd will tell you that we get pilgrims from all over the country. (Hi guys!)

I see you're fairly new here. Here are links to our last two GTG's. Welcome to the forum.

2010 - http://forums.audioholics.com/forums/showthread.php?t=67150&highlight=oregon+gtg

2009 - http://forums.audioholics.com/forums/showthread.php?t=53440&highlight=oregon+gtg and here is a wrap-up thread http://forums.audioholics.com/forums/showthread.php?t=59584&highlight=oregon+gtg

 

[GranteedEV]

Also under consideration is MTM design vs. a three way. As I understand it, in a three way, the mid-driver is relieved of bass duties, thereby allowing a cleaner, more distortion free midrange, & giving deeper bass at the same time, depending on the woofer of course.

On paper, but of course in execution there's a lot of factors in what we consider "distortion". Driving spacing/lobing/phase/cavity effect/cascading driver response may all be more complex factors with 3-ways keeping them from having the exact same coherency.

I'm not saying 2-ways are better, or 2.5 ways, or 3-ways or 4 ways or 2-ways with multi subs or whatever. There's more factors at play than just that. The speaker I want to build when i save up enough disposable income, the Nao Note, is effectively a 4(.5) way

 

[Patrukas777]

I'm not saying 2-ways are better, or 2.5 ways, or 3-ways or 4 ways or 2-ways with multi subs or whatever. There's more factors at play than just that. The speaker I want to build when i save up enough disposable income, the Nao Note, is effectively a 4(.5) way

any idea how much the NaO Note costs to build?