New DIY MTM Towers designed by Dennis Murphy and Paul Kittinger

[Swerd]

Based on your suggestion, I'm planning to veneer the front of the cabinet and then glue (no screws) the a prefinished outer front baffle directly on the veneer. I'm using wood backed veneer and will apply using clamps and cauls. Is there any concern for the veneer pulling apart when it has to bear the load of the outer front baffle (including drivers)? I'm not concerned about glue failure, but I am concerned about whether the veneer will separate from its wood backer.

I never thought of that before. So, I have to say I don't know for certain, but I suspect it's not a problem.

When you drill screw holes for the drivers, you have the thickness of two layers of MDF (1½") to work with. Use 1" to 1¼" long #8 wood screws, and you'll be attaching the heavy woofers to the inner baffle layer.

 

[Researcher]

Well well, I posted my first comment last september 1st on this thread, and just finished building them a couple days ago...

I want to say thanks to everyone posting information, tips and opinions about this design. And it has been quite a journey from start to finish, prior to this I never worked on something of this size before, it was very time consuming and challenging for sure. I don't know if someone has any info about how much the enclosures weight without drivers, but man they are heavy!...building the box itself was the easy part, and apart from some rethinking a connection in the low pass crossover everything went fine.

Veneering this thing was an authenthic PITA and the hardest step for me, I burnt an iron in the process and had to buy a new one!, bubbles started to appear here and there so I took me almost a week to get rid of the bigger ones, allowing time for the glue to dry properly, I spent the last 2 weeks just giving them a decent look.

The iron/glue method seems to work best on small panels, I still don't know why bubbles started to appear in one side or the other randomly, used 2 coats of glue on each side letting it dry and then ironing, in fact I achieved 2 totally flat bubble free large sides. Then applyed 3 coats of a thing called nitrocelluse sealer and 4 coats of varnish sanding between coats and black enamel in the front baffle. Anyway, finishing it's such a boring process it's something I'd prefer someone else to do it because it can be screwed so easily, it's my least favourite stage when building speakers by far.

Now to what matters the most, sounding impressions, these are definitely a huge upgrade from what I had as front speakers in the past and are much more efficient in terms of sensitivity, the 8 watt tube amp seems to drive them very well, I played a copy of The Flecktones Flight of the Cosmic Hippo self titled track on vinyl (great track to test speakers IMO) and this was the ultimate bass response test, very accurate, not boomy but strong and clean at the same time.

After some hours playing a wide range of material from many sources CDs, DVDs, mp3s, flac, vinyl, etc; I think these are quite unforgiving speakers; poorly recorded material definitely it's going to sound terrible, obviously when the recording it's very good the performance it's superb.

I'm satisfied with their performance overall, perhaps didn't expected them to be so revealing. I also hooked them to the 5.1 system, and started to listen to sound effects from series, documentaries and movies I never imagined they were there, this leads me to a question: I'm planning to build the center channel later this year, but what about the surrounds?...I've been using a pair of P. Carmody's Speedsters which I think it's a great design but overkill for this task, and sound a bit more "bright" than the ER18s...I suppose there're better options to integrate the 3 frontal speakers and the 2 rear ones?...anyone?

Again thanks for the feedback and keeping this thread alive, this is a great project with a great design.

 

[Swerd]

Great looking speakers, congratulations! Thanks for the photos.

When you got the bubbles under the veneer, how did you remove them? Did you pierce the veneer with a sharp needle at the center of the bubble and iron them out?

My thoughts on finishing are much the same as yours. It's slow work and you see every mistake. The good news is that you are the only person who knows where those little mistakes are. Don't tell anyone else and they'll never see them . If you keep the lights low and don't examine them closely, you won't see them either .

The revealing sound is a hallmark of Dennis Murphy's speaker designs. I find it addicting.

Meeting the sound quality of the ER18 MTMs and ER15 Center would require more cost than I think it's worth for rear channel speakers. I guess I don't have the same expectations of rear channel speakers as I do for the front 3 speakers. Personally, I find speakers like NHT SuperZeros are good for rear channel duty. They're small, don't do much bass, and they have an overall neutral sound balance – and they're already finished.

 

[Researcher]

Great looking speakers, congratulations! Thanks for the photos.

When you got the bubbles under the veneer, how did you remove them? Did you pierce the veneer with a sharp needle at the center of the bubble and iron them out?

Hi Swerd, thanks for the compliment, yeah I used the old trick of piercing the bubble and use a syringe to inject some glue, then clamping with a flat piece of MDF and wax paper; after sanding and varnishing the "wounds" are barely visible.

And yes you're right, the way we look to these projects while working on them are different from anyone else's point of view, I tend to sweat the small stuff, so I'm quite slow in some stages overthinking and trying to avoid any costly mistakes; plus I don't build speakers every month...so every time it's like re-learning.

I filled each one with 16 oz polyfill, the instructions mentioned 17-18 oz, I don't know if that could make a listenable difference, and didn't added gasketing tape to the mid/bass drivers, just tightened the screws very hard (still have blisters in my hand!!), but again I don't know if this could make any difference.

 

[roadrune]

Why not build a second pair of er18's and use them as surround speakers? Depending on your HT it might be a good idea to build them higher (but keep the bottomplate in the right place so you dont change the internal volume). Thats my plan anyway, in my head it sounds like a good idea anyway, and it is my plan to build 3pairs of er18 for my HT project. Newer movies tend to have more fulltone information in all channels, hence the need for speakers with good bass for surround and sides.

Anyway i will start building the first pair within next month i think

Sorry for the language, i am from the homeland of SEAS

 

[Swerd]

I filled each one with 16 oz polyfill, the instructions mentioned 17-18 oz, I don't know if that could make a listenable difference, and didn't added gasketing tape to the mid/bass drivers, just tightened the screws very hard (still have blisters in my hand!!), but again I don't know if this could make any difference.

I'm pretty sure that using 16 oz polyfill, instead of 17-18 oz, will not make a significant difference. But I haven't tested that. If I remember polyfill is sold in 16 oz bags. It's easy to buy two bags and use one per cabinet.

I don't remember if those woofers come with gaskets built-in to the frame. Of course, you wouldn't be asking about this if they did. I guess it only matters if you have an air leak. That depends on how smooth your recess cuts were when you routed them. In my hands, they occasionally leak, and I'm not very good at recognizing an air leak by ear. As a result, I always use a gasket. My favorite type is the black wax-like gasket caulk sold by Parts Express. It comes in 12" long strings, and I roll them out so they are thinner and longer. As I drive in the screws, I tighten them, compressing the caulk, until the driver's frame is flush with the baffle. The gasket tape PE sells also works, but it can be thicker and you have to account for that by routing the recess deeper.

 

[slipperybidness]

Well well, I posted my first comment last september 1st on this thread, and just finished building them a couple days ago...

View attachment 17808

I want to say thanks to everyone posting information, tips and opinions about this design. And it has been quite a journey from start to finish, prior to this I never worked on something of this size before, it was very time consuming and challenging for sure. I don't know if someone has any info about how much the enclosures weight without drivers, but man they are heavy!...building the box itself was the easy part, and apart from some rethinking a connection in the low pass crossover everything went fine.

Veneering this thing was an authenthic PITA and the hardest step for me, I burnt an iron in the process and had to buy a new one!, bubbles started to appear here and there so I took me almost a week to get rid of the bigger ones, allowing time for the glue to dry properly, I spent the last 2 weeks just giving them a decent look.

The iron/glue method seems to work best on small panels, I still don't know why bubbles started to appear in one side or the other randomly, used 2 coats of glue on each side letting it dry and then ironing, in fact I achieved 2 totally flat bubble free large sides. Then applyed 3 coats of a thing called nitrocelluse sealer and 4 coats of varnish sanding between coats and black enamel in the front baffle. Anyway, finishing it's such a boring process it's something I'd prefer someone else to do it because it can be screwed so easily, it's my least favourite stage when building speakers by far.

Now to what matters the most, sounding impressions, these are definitely a huge upgrade from what I had as front speakers in the past and are much more efficient in terms of sensitivity, the 8 watt tube amp seems to drive them very well, I played a copy of The Flecktones Flight of the Cosmic Hippo self titled track on vinyl (great track to test speakers IMO) and this was the ultimate bass response test, very accurate, not boomy but strong and clean at the same time.

After some hours playing a wide range of material from many sources CDs, DVDs, mp3s, flac, vinyl, etc; I think these are quite unforgiving speakers; poorly recorded material definitely it's going to sound terrible, obviously when the recording it's very good the performance it's superb.

I'm satisfied with their performance overall, perhaps didn't expected them to be so revealing. I also hooked them to the 5.1 system, and started to listen to sound effects from series, documentaries and movies I never imagined they were there, this leads me to a question: I'm planning to build the center channel later this year, but what about the surrounds?...I've been using a pair of P. Carmody's Speedsters which I think it's a great design but overkill for this task, and sound a bit more "bright" than the ER18s...I suppose there're better options to integrate the 3 frontal speakers and the 2 rear ones?...anyone?

Again thanks for the feedback and keeping this thread alive, this is a great project with a great design.

Go over to Philharmonic Audio and pick up a set of Dennis's Affordable Accuracy Monitors for surrounds.

 

[Swerd]

Go over to Philharmonic Audio and pick up a set of Dennis's Affordable Accuracy Monitors for surrounds.

Yes, I completely agree. And I completely forgot to mention them earlier.

Philharmonic Audio Affordable Accuracy Monitor

 

[roadrune]

Quick question for you who have (and have heard) theese speakers, what would you compare them with of commercial speakers when it comes to performance?

From what i have read this really seams as the perfect set for me, but it would be fun to hear what you guys would compare them to while im waiting to get started with my build.

I am well known with B&Ws and Dali speakers, is there any similar in their range?

 

[Swerd]

Quick question for you who have (and have heard) theese speakers, what would you compare them with of commercial speakers when it comes to performance?

From what i have read this really seams as the perfect set for me, but it would be fun to hear what you guys would compare them to while im waiting to get started with my build.

I am well known with B&Ws and Dali speakers, is there any similar in their range?

I believe the ER18 MTM speakers are most like the commercially available speakers made by Salk:

Salk SongTowers

Salk Veracity HT-TL

See post #2 at the beginning of this thread:

There is a new DIY design that bears a very strong family resemblance to both the Salk SongTower and its big brother the Salk HT2-TL. The woofer and tweeter choice and the crossover design of this DIY speaker is the work of Dennis Murphy who designed many of the Salk products including the SongTower and the HT2-TL. Paul Kittinger designed the mass-loaded transmission line (MLTL) cabinet for this new speaker, using the same method as he used for those two very successful Salk models.

In Norway, you may not be familiar with them. All of these Salk speakers and the ER18 MTM were designed by the same crossover designer, Dennis Murphy, and they also share the transmission line cabinet designer Paul Kittinger. I consider the SEAS Thor as similar sounding to the Salk Veracity HT2-TL. The Salk has an arguably better tweeter.

I have not heard any of the Dali speakers, but I am somewhat familiar with the B&Ws. The B&W 800 series speakers are very good, and very expensive. The ER18 MTMs easily out perform any of the B&W 600 or CM series speakers.

 

[roadrune]

Thanks Swerd, i am not familiar with Salk, so you are correct there

Dali is a danish manufacturer who started with affordable hifi speakers back in the 80's, now they are getting really good, and the reason i found this thread was that i asked for a diy speaker who could compare to the new Dali Opticon 6 on a Norwegian forum, and a guy there directed me here. The Opticon 6 is ment as a competitor for B&W 683 (whitch i own) with the same pricetag, however i find them better with deeper and nicer bass, and with a hybrid tweeter with both dome and ribbon it have a great high end as well.

 

[Swerd]

Dali speakers are sold in the USA, but I have never heard one. I found reviews of 3 different Dali speakers that do have frequency response measurements. The reviews were all in Stereophile. The reviewer's written comments are often entertaining fiction, but their speaker measurements are considered to be reliable.

I don't know which of these are most comparable to the Opticon 6 speakers, but all of them share a common profile in their frequency response curves. The have a somewhat exaggerated bass and an elevated high treble response, with a recessed midrange. I haven't heard any of these. I am only making an educated guess of what they may sound like from looking at the Stereophile measurements.

The ER18 MTMs have a smoother and flatter frequency response curve over the entire audio range than the Dalis. It is my guess that they will sound more detailed than the Dalis, without sounding unpleasantly brighter. At first listen, they may sound to you like they have less bass. With time, you will realize the bass is not missing, in fact, I think that transmission line bass is remarkable and cleaner sounding, unlike anything I have previously known. The lack of exaggerated bass removes a muddy sounding lower midrange noise that you may never have noticed before.

Dali Helicon 400

Dali Ikon 6

Dali Rubicon 8

 

[roadrune]

Of the speakers you list there, onle the Rubicon series are still available, and the 8 is a larger model using 8" woofers.

However this just makes me more excited to get building

Just a couple of weeks offshore first...

Anyone else have an opinion about the sound, and about using theese as surrounds?

 

[ARES24]

I think the ER18's are the best speakers I have ever heard, granted I have only had limited experience with other high end speakers.
Using these as surrounds?... I am drooling, yes I want that.....

 

[fuzz092888]

I think the ER18's are the best speakers I have ever heard, granted I have only had limited experience with other high end speakers.
Using these as surrounds?... I am drooling, yes I want that.....

I am definitely pro good surrounds.

 

[Alex2507]

I am definitely pro good surrounds.

Let's be clear. You are definitely pro excess in every aspect of H/T. Carry on.

 

[fuzz092888]

Let's be clear. You are definitely pro excess in every aspect of H/T. Carry on.

Touche

 

[David LR]

Well well, I posted my first comment last september 1st on this thread, and just finished building them a couple days ago...

View attachment 17808

I want to say thanks to everyone posting information, tips and opinions about this design. And it has been quite a journey from start to finish, prior to this I never worked on something of this size before, it was very time consuming and challenging for sure. I don't know if someone has any info about how much the enclosures weight without drivers, but man they are heavy!...building the box itself was the easy part, and apart from some rethinking a connection in the low pass crossover everything went fine.

Veneering this thing was an authenthic PITA and the hardest step for me, I burnt an iron in the process and had to buy a new one!, bubbles started to appear here and there so I took me almost a week to get rid of the bigger ones, allowing time for the glue to dry properly, I spent the last 2 weeks just giving them a decent look.

.

Researcher-

Congrats on finishing and building a nice looking pair of speakers. At least it didn't take you four years
like it did me ! I agree, it's a time consuming & challenging journey. I've built several smaller speakers but nothing this physically large. Just the size means more work, more square footage to cover with veneer, heavier speakers to heave around, more money on veneer, etc. I also had problems with veneer where I hadn't with the smaller speakers although my problems were with veneer peeling & not adhering at the edges. Like you, I carefully inserted glue & clamped with scrap wood wrapped in wax paper. I think my problems stemmed from having an iron that wasn't hot enough. Finally got everything to stick though, they look and sound great.

Will you be building the ER15 center channel to with these ? I'm considering that even though the ER15 uses a ribbon tweeter while I built the dome tweeter version of the ER18s. Seems like they should blend though, maybe even compliment each other.

 

[roadrune]

Will you be building the ER15 center channel to with these ? I'm considering that even though the ER15 uses a ribbon tweeter while I built the dome tweeter version of the ER18s. Seems like they should blend though, maybe even compliment each other.

"You talking to me?"

Yes, i plan to build the er15 center, but obviously i want to build a pair of er18's first and get a good listen to them before i build anything else. If they are as good as i suspect, then i will build a second pair for surrounds as i already have a center that will have to do for a period, and later on the er 15 and the third pair er18 for sides.

And then a couple of subs, oh, and i forgot, also a 7-channel power amp maybe i'll finish within 2018...

 

[David LR]

"You talking to me?"

Yes, i plan to build the er15 center, but obviously i want to build a pair of er18's first and get a good listen to them before i build anything else. If they are as good as i suspect, then i will build a second pair for surrounds as i already have a center that will have to do for a period, and later on the er 15 and the third pair er18 for sides.

And then a couple of subs, oh, and i forgot, also a 7-channel power amp maybe i'll finish within 2018...

OK, well, better you than me. With my track record it would take me 10 years build that many speakers !
Sounds like fun though.