New DIY MTM Towers designed by Dennis Murphy and Paul Kittinger

[GranteedEV]

Got a chance to go over to Meniscus again yesterday, they called because the speakers I was talking about a couple posts ago were finished and I told him I wanted to listen when they were done w/ em. Holy smokes do they ever sound good!!!

I think you're hooked on speakers

He said they were around $12k! He also said he had around $3k just into xover components !

people sure are crazy!

With that kind of money why not just get a DEQX!?

 

[DirkL]

ER18 MTMs Bass port design

Hi,
I am currently preapring the cabinets for the ER18 built.
After checking the documents (special thanks to Swerd for his support!!) I decided to buy some 3" ports from Precision Ports. Unfortunately these guys do not provide any other dimensions of their ports, other than diameter and length.
The ports, once arrived, are flared type and I mean 'flared'. They look more like a horn at both ends, with flares longer than 1" (30mm). The outer diameter of the 3" ports at the exit will then be about 5". Does anyone have some experience with the influence on the length dimensioning inside the mass-loaded transmission line of the ER18s?
There is some allowance for the flares, but I guess those horn-like flares from PP are not considered. Alternatively I would consider to remove the flares and bevel the opening of the cabinet instead.
Appreciate your thoughts to this...

 

[mattsk8]

Hi,
I am currently preapring the cabinets for the ER18 built.
After checking the documents (special thanks to Swerd for his support!!) I decided to buy some 3" ports from Precision Ports. Unfortunately these guys do not provide any other dimensions of their ports, other than diameter and length.
The ports, once arrived, are flared type and I mean 'flared'. They look more like a horn at both ends, with flares longer than 1" (30mm). The outer diameter of the 3" ports at the exit will then be about 5". Does anyone have some experience with the influence on the length dimensioning inside the mass-loaded transmission line of the ER18s?
There is some allowance for the flares, but I guess those horn-like flares from PP are not considered. Alternatively I would consider to remove the flares and bevel the opening of the cabinet instead.
Appreciate your thoughts to this...

Sorry, no help to you on the ports at all. Just wanted to say take tons of pics ! You should also start your own thread so we can all see your progress! Can't wait to watch em come to life!

 

[Swerd]

Hi,
I am currently preapring the cabinets for the ER18 built.
After checking the documents (special thanks to Swerd for his support!!) I decided to buy some 3" ports from Precision Ports. Unfortunately these guys do not provide any other dimensions of their ports, other than diameter and length.
The ports, once arrived, are flared type and I mean 'flared'. They look more like a horn at both ends, with flares longer than 1" (30mm). The outer diameter of the 3" ports at the exit will then be about 5". Does anyone have some experience with the influence on the length dimensioning inside the mass-loaded transmission line of the ER18s?
There is some allowance for the flares, but I guess those horn-like flares from PP are not considered. Alternatively I would consider to remove the flares and bevel the opening of the cabinet instead.
Appreciate your thoughts to this...

According to Paul Kittinger,

The port’s length, if not flared, is 2¾" long. If flared on one end, make it 3¼" long. If flared on both ends make it 3¾" long.

This includes products like the 3" diameter Precision Port. Make the total port length 3¾" (9.5 cm) long. If I recall, Precision Port includes instructions that should tell what size holes to make.

 

[Peterselie]

I like this MTM's. Is there a website where I can download the plans?

 

[skyline_123]

Welcome to the forums!

Swerd can give you a complete PDF if you PM him. Although, I think you'll need 5 posts or something like that to PM someone. You can use the Post Pad to get your count up. If not, the first page of this thread contains all the necessary plans to complete the build.

To make things real easy, MeniscusAudio.com now has a kit for both versions of this design, the ribbon and dome tweeters.

Keep everyone informed if you do build these, you won't be disappointed!

 

[doors666]

I like this MTM's. Is there a website where I can download the plans?

save the first page of this thread on your hard disk

 

[capricious]

Surprised that this design hasn't caught people's attention everywhere. I would've thought people would be building this kit left right and center
I have been looking to build a slim floorstander for a while, and this certainly fits the bill. The BOM has gone up by atleast 15-20% since the first post, but i still think its a good price for a kit that DMurphy and PaulK signed off on.
A quick question though to the designers - Since this design is a couple of years old ... has the XO or driver selection been revisited? I'm sure the speaker sounds great as-is, but i'm just asking.

While i hunt for used drivers, i'll get started on the cabinets, and post my progress. Can someone please post/attach the pdf plans someplace?

 

[plmedeiros]

Power handling?

Hi,

Does anyone know what the power handling of these are? I noticed that the power handling of the Fountek NeoCD3 ribbon is 17 watts nominal, 40 watts max. Also, I have the pdf design build and one of the plots states that the SEAS ER18RNX driver reaches xmax with 16.8watts at 18Hz. I'm thinking of building these I'm not sure if they can handle HT?

Thanks.
Paul

 

[Swerd]

A quick question though to the designers - Since this design is a couple of years old ... has the XO or driver selection been revisited? I'm sure the speaker sounds great as-is, but i'm just asking.

While i hunt for used drivers, i'll get started on the cabinets, and post my progress. Can someone please post/attach the pdf plans someplace?

I'm not either of the designers, but I wrote the description and plans. Send me a PM with your email address, and I'll send you a copy of the plans in a pdf file. Posts 2 & 3 in this thread have the same information.

The original drivers and crossover have not changed. Note that two versions exist, one with a dome tweeter and the other with a ribbon tweeter. Each version uses a different crossover.

Richard

 

[Swerd]

Does anyone know what the power handling of these are? I noticed that the power handling of the Fountek NeoCD3 ribbon is 17 watts nominal, 40 watts max. Also, I have the pdf design build and one of the plots states that the SEAS ER18RNX driver reaches xmax with 16.8watts at 18Hz. I'm thinking of building these I'm not sure if they can handle HT?

Paul

These speakers have an F3 of about 35 Hz, and produce useful sound as low as 31 Hz. Below 30 Hz, output drops off quickly. The comment about Xmax at 18 Hz is only meant to say that at all frequencies above 18 Hz the woofers will move less than Xmax (6 mm) and will not be damaged by being overdriven. They cannot produce any real sound that low, and a subwoofer should be added for HT use. My guess is that a good crossover frequency might be 40 or 60 Hz. That can easily be determined with trial and error.

The power handling of the Fountek tweeter is plenty sufficient for HT use. Typically sound in the range of 2.5 kHz and higher is of much lower power than the power drawn by the woofers.

 

[capricious]

Hi Richard,

I've sent you a PM.

Thanks!

 

[capricious]

Received the attachment. Thanks a lot, Richard!

 

[plmedeiros]

Richard[/QUOTE]

Paul

These speakers have an F3 of about 35 Hz, and produce useful sound as low as 31 Hz. Below 30 Hz, output drops off quickly. The comment about Xmax at 18 Hz is only meant to say that at all frequencies above 18 Hz the woofers will move less than Xmax (6 mm) and will not be damaged by being overdriven. They cannot produce any real sound that low, and a subwoofer should be added for HT use. My guess is that a good crossover frequency might be 40 or 60 Hz. That can easily be determined with trial and error.

The power handling of the Fountek tweeter is plenty sufficient for HT use. Typically sound in the range of 2.5 kHz and higher is of much lower power than the power drawn by the woofers.

Hi Richard,

Thanks for your response. I guess I'm a little confused, are you saying that the drivers will never see 16.8 watts at 18 Hz? I understand that the SPL at that frequency is very low (-27dB) compared to frequencies greater than 35Hz but I'n not sure what SPL has to do with a driver reaching its Xmax?

Thanks,
Paul

 

[Swerd]

Thanks for your response. I guess I'm a little confused, are you saying that the drivers will never see 16.8 watts at 18 Hz? I understand that the SPL at that frequency is very low (-27dB) compared to frequencies greater than 35Hz but I'n not sure what SPL has to do with a driver reaching its Xmax?

Please remember that the graph you are thinking of, the one that shows the Xmax peak at 18 Hz, is a prediction of the performance those ER18 woofers in the cabinet Paul Kittinger designed. I don't know, for certain, if this can cause speaker damage as it is only a prediction of voice coil excursion.

I do understand your concern about power handling, and can confidently say that these SEAS 7" woofers are quite robust, probably more sturdy than most 6½ to 7" woofers available. The ER18 MTMs can easily handle any music I know of at playback levels very loud to my ears while using a 200 wpc amp. For action movies with studio-generated LFE content, I would advise using a subwoofer for these speakers. Set the AVR's high-pass filter to a frequency high enough, such as 40 Hz, to avoid exposing these speakers to strong signals below 20 Hz. This advice is no different that what I would say in general for any similar sized speaker.

 

[plmedeiros]

Please remember that the graph you are thinking of, the one that shows the Xmax peak at 18 Hz, is a prediction of the performance those ER18 woofers in the cabinet Paul Kittinger designed. I don't know, for certain, if this can cause speaker damage as it is only a prediction of voice coil excursion.

I do understand your concern about power handling, and can confidently say that these SEAS 7" woofers are quite robust, probably more sturdy than most 6½ to 7" woofers available. The ER18 MTMs can easily handle any music I know of at playback levels very loud to my ears while using a 200 wpc amp. For action movies with studio-generated LFE content, I would advise using a subwoofer for these speakers. Set the AVR's high-pass filter to a frequency high enough, such as 40 Hz, to avoid exposing these speakers to strong signals below 20 Hz. This advice is no different that what I would say in general for any similar sized speaker.

Thanks Richard. It didn't even occur to me that I should be concerned about Xmax at 18 Hz, until I spotted that graph. I've been looking at this design because it uses two drivers, which promotes greater power handling. Did you build these? I've been looking at Paul K's other designs as well but thought the MTM would serve me better for HT applications.

Thanks again,
Paul

 

[Swerd]

Thanks Richard. It didn't even occur to me that I should be concerned about Xmax at 18 Hz, until I spotted that graph. I've been looking at this design because it uses two drivers, which promotes greater power handling. Did you build these? I've been looking at Paul K's other designs as well but thought the MTM would serve me better for HT applications.

Thanks again,
Paul

No I didn't build these speakers, but I did hear the prototype that Dennis used when he developed the design. He had an unfinished MDF cabinet that was a "mule" for the original Salk HT2-TL design. The cabinet dimensions for these two designs are virtually identical. He put in the ER18s and Fountek ribbon tweet, and later the Dayton RS28 dome, and worked out appropriate crossovers. So I was able to listen to one of these speakers in mono, and I was very impressed. If I wasn't happy with my SongTowers, I would definitely build a pair of these. Paul's ability at tuning a cabinet's bass response and Dennis's voicing of the midrange and his sense of off-axis dispersion make for an outstanding combination.

Good luck with your build, and please keep us posted with your questions & progress.

 

[plmedeiros]

No I didn't build these speakers, but I did hear the prototype that Dennis used when he developed the design. He had an unfinished MDF cabinet that was a "mule" for the original Salk HT2-TL design. The cabinet dimensions for these two designs are virtually identical. He put in the ER18s and Fountek ribbon tweet, and later the Dayton RS28 dome, and worked out appropriate crossovers. So I was able to listen to one of these speakers in mono, and I was very impressed. If I wasn't happy with my SongTowers, I would definitely build a pair of these. Paul's ability at tuning a cabinet's bass response and Dennis's voicing of the midrange and his sense of off-axis dispersion make for an outstanding combination.

Good luck with your build, and please keep us posted with your questions & progress.

I've got to say that you are one of the most responsive audio forum members that I have ever come across! Much appreciated. I am leaning heavily toward building these. Now all I have to do is decide whether to veneer (invest in a press) or wrap 1/2" mdf in hardwood.

Thanks again,
Paul

 

[skyline_123]

+1 on your comment about Swerd. He is both wise and responsive (and I'm sure devilishly handsome).

I too thought about going the vacuum press route. Once I priced everything out, which included the vacuum pump, I realized I was in over my head for something that I won't use too often. I've had relatively good success with contact cement on a small pair of speakers but I have not done anything as large as the ER18's.

Regarding your construction, I'm not sure if I would mess with 1/2" mdf. Even though you're going to wrap it in hardwood, I assume you would be making the braces out of the mdf as well. For bracing, I would use at least 3/4". You could laminate your half inch stuff to make 1" bracing I suppose. Either way, I'd stick with 3/4" just to be safe.

I look forward to seeing some progress pics and a review.

 

[plmedeiros]

+1 on your comment about Swerd. He is both wise and responsive (and I'm sure devilishly handsome).

I too thought about going the vacuum press route. Once I priced everything out, which included the vacuum pump, I realized I was in over my head for something that I won't use too often. I've had relatively good success with contact cement on a small pair of speakers but I have not done anything as large as the ER18's.

Regarding your construction, I'm not sure if I would mess with 1/2" mdf. Even though you're going to wrap it in hardwood, I assume you would be making the braces out of the mdf as well. For bracing, I would use at least 3/4". You could laminate your half inch stuff to make 1" bracing I suppose. Either way, I'd stick with 3/4" just to be safe.

I look forward to seeing some progress pics and a review.

Thanks for the advise. I'm at the beginning stages of researching a vacuum setup. I would much rather pay someone locally to veneer the panels. I've read that some have wrapped MDF with hardwood with mixed results. It seems a bit overkill. I may just have to build them out of 3/4" MDF and worry about the finish later, which may be a solid year away. Spring time is right around the corner and what little spare time I currently have will be non existent.

By the way, very nice thread you've put together. It will serve me well once I start the project. Hopefully within the next couple of weeks. I'll be sure to provide pics once I start it.

Thanks,
Paul