DIY MTM Transmission Line Design - Help Needed

[saikatbiswas82]

Hi All,
I am planning to build my first DIY towers in next few months. After reading a lot about different designs, I've decided to go for a TL design. I've shortlisted the following drivers/components combo:

BAJAAO TriTrix MTM TL Speaker Kit Components Only Pair

The original parts-express link is here:

TriTrix MTM TL Speaker Components And Cabinet Kit Pair | 300-702


As per parts-express the design of the TL is lke this:

IMG#1

I am considering another TL design as well. This design is having only 1 woofer. I'll modify the design for MTM later.

IMG#2

Now my questions to gurus are:

1. I do understand that the parts-express design is tried and tested but if I consider the later design (i.e. IMG#2) what could be the advantages/disadvantages of the same?

2. I've read that the parts-express TL produces around 75watt RMS. Is there a better solution I could get under 25K (INR) all inclusive?

3. Should I go for the transmission line design? The primary usage would be for movies (60%) / music (40%) (sometimes its 70% movies and 30% music). I do have a pair of Monitor Audio BX2. If the DIY sounds better than BX2s, I could put them for surrounds as well.


If the DIY tower sounds better, I'll go for the DIY center as per the following design:

IMG#3

.

TriTrix design has been take from:
Tritrix_pg_3

But, in case my BX2s sounds better than DIY TL, I'll keep BX2s for LR and go for BX Center.

Suggestions/Opinions welcome.

 

[saikatbiswas82]

72 views but no replies. Please help!

 

[saikatbiswas82]

Hi All,
I've created a new TL design using sketchup. Please find the images below:

IMG#1

IMG#2

IMG#3

The cabinet dimensions are: 7.5"x36"x15" (Width x Height x Depth).

1. What are the modifications should I make to this design?
2. Should I go ahead with this design or should I stick to Tritrix design only?
3. Is there a chance this design might sound better than default Tritrix TL design?
4. Should I go with this MTM design? Or should I consider TM/MT design for transmission line?
5. Should I stick to this crossover/driver selection or should I consider seperate elements for the same?
6. Should I stick to this 2nd order crossover or should I consider 3rd order crossover for this design?

Note: I've created another thread in diyaudio.com as well.
Link: http://www.diyaudio.com/forums/multi-way/246163-diy-mtm-transmission-line-design-help-needed.html

Any suggestion/opinion will be highly appreciated.

 

[Prasad Karpe]

You better have contact by PM to our forum member Mr.Hari Iyer. He is the real authority in this matter.

regards
Prasad

 

[saikatbiswas82]

You better have contact by PM to our forum member Mr.Hari Iyer. He is the real authority in this matter.

regards
Prasad

Thanks a lot for pointing this out Prasad. I've send a PM to Mr. Hari Iyer. I am waiting for his reply.

 

[doors666]

dude, if u are going wit the tritrix drivers, go with the published tritrix design. at your design skill level, whatever changes you do will probably make it worse.

what full range driver are you talking about in the single woofer design. And if its not a full range driver, then its anyway a waste of time, effort and money.

I havent heard the bx2, but it will most probably beat the pants off that one, specially in the bass response.

there are huge threads on techtalk part s express forums for tritrix... read those...

 

[Prasad Karpe]

@saikatbisws82

You can find some more interesting designs here



The designs are for fostex drivers though

regards
Prasad

 

[kapvin]

Hi All,
I am planning to build my first DIY towers in next few months. After reading a lot about different designs, I've decided to go for a TL design. I've shortlisted the following drivers/components combo:

BAJAAO TriTrix MTM TL Speaker Kit Components Only Pair

The original parts-express link is here:

TriTrix MTM TL Speaker Components And Cabinet Kit Pair | 300-702


As per parts-express the design of the TL is lke this:

IMG#1

I am considering another TL design as well. This design is having only 1 woofer. I'll modify the design for MTM later.

IMG#2

Now my questions to gurus are:

1. I do understand that the parts-express design is tried and tested but if I consider the later design (i.e. IMG#2) what could be the advantages/disadvantages of the same?

2. I've read that the parts-express TL produces around 75watt RMS. Is there a better solution I could get under 25K (INR) all inclusive?

3. Should I go for the transmission line design? The primary usage would be for movies (60%) / music (40%) (sometimes its 70% movies and 30% music). I do have a pair of Monitor Audio BX2. If the DIY sounds better than BX2s, I could put them for surrounds as well.


If the DIY tower sounds better, I'll go for the DIY center as per the following design:

IMG#3

.

TriTrix design has been take from:
Tritrix_pg_3

But, in case my BX2s sounds better than DIY TL, I'll keep BX2s for LR and go for BX Center.

Suggestions/Opinions welcome.

the tritrix is supposed to be a really well regarded design. on a price performance equation; i've only heard good things about it.


however, since the tritrix design uses speakers with well published specs, if you are really interested, do let me know your objective of speaker redesign, and maybe I can model another enclosure for you. then you can do a sketch-up of it.

do write the following

1. your objective of not following tritrix eg - more extension; less size or what
2. are you only looking at TL or is ML-Tl or bass reflex also open?

all the best

 

[ghatgepatil]

This article may be of some help ..... http://www.kt.agh.edu.pl/~natkanie/papers/TLS.pdf

Yet another detailed link ..... http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Optimo_copy.pdf

 

[tcpip]

Saikat,

Just curious -- are you aware of this famous chap Martin J King, whose work in the MLQWTL (mass loaded quarter-wave transmission line) area is something like a baseline from which everyone seems to start? I've never designed one, so no personal experience. Check this site.

But maybe you've already studied this stuff.

 

[saikatbiswas82]

First, I am awefully sorry that I couldn't take a look at the suggestion/articles you've shared as I was out of town.

Thank you everyone for your time.

dude, if u are going wit the tritrix drivers, go with the published tritrix design. at your design skill level, whatever changes you do will probably make it worse.

what full range driver are you talking about in the single woofer design. And if its not a full range driver, then its anyway a waste of time, effort and money.

I havent heard the bx2, but it will most probably beat the pants off that one, specially in the bass response.

there are huge threads on techtalk part s express forums for tritrix... read those...

@doors666... thanks a lot for your valuable suggestions.

the tritrix is supposed to be a really well regarded design. on a price performance equation; i've only heard good things about it.

@kapvin... my objective is to build a pair of floorstanders. My room size is 13.5'X9.5'. A pair of bookshelves might be sufficient enough for my room but I am always fascinated by the looks of tower speakers.

The reason why I was inclined to TL over bass reflex is - I found through my initial reading that TLs produce more clarity over midranges (please correct me if I am wrong). As I already have a dedicated sub and intend to upgrade the sub sometime next year, I need the midranges loud and clear.

however, since the tritrix design uses speakers with well published specs, if you are really interested, do let me know your objective of speaker redesign, and maybe I can model another enclosure for you. then you can do a sketch-up of it.

That's an awesome offer I can't refuse . Could you please share any sketch with me whenever you have time. I am in no hurry. Thanks a lot for the offer.

do write the following

1. your objective of not following tritrix eg - more extension; less size or what

As I live in a small apartment, I won't be having too much space left from the back of the speaker and wall. So it would be better If I could design a TL with the open end at the front.
To be very honest, I did not understand the quarter-wave theory properly. But I believe guys like you are always here to educate me. I am counting on you (and everyone else as well).

BTW... my preferred cabinet dimensions (external dimensions)
Height: 36" - 42"
Width: 7" - 8"
Depth: Anything less than 20"

2. are you only looking at TL or is ML-Tl or bass reflex also open?

all the best

I believe I am not stubborn. I am ready to accept any design that might sound better. I am open to suggestions here. I am open for TL or Bass Reflex or Sealed or anything else. SQ is the top priority.

This article may be of some help ..... http://www.kt.agh.edu.pl/~natkanie/papers/TLS.pdf

Yet another detailed link ..... http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Optimo_copy.pdf

@ghatgepatil... these are awesome articles worth reading. Thanks for sharing the same.

As my preference is 2-way or 2.5-way, I liked the following design as this one has open port at the front:
Article: http://www.kt.agh.edu.pl/~natkanie/papers/TLS.pdf
Page: 4
Fig. 8
Third from the left.

Saikat,

Just curious -- are you aware of this famous chap Martin J King, whose work in the MLQWTL (mass loaded quarter-wave transmission line) area is something like a baseline from which everyone seems to start? I've never designed one, so no personal experience. Check this site.

But maybe you've already studied this stuff.

@tcpip.... I've come across the site fortunately. But as I've stated above, I could not understand the theory properly.


To All,
I was considering the TriTrix design because I had a chance to bring those drivers from US and I don't have to take the pain of determining crossover components by myself. Looking the current scenario, I think I won't be having that opportunity and have to procure the drivers/parts locally.

So I was giving a second thought to go for Peerless drivers and building the crossover from scratch. Please suggest whether that's a good idea (!!??)

Please consider that due to my budget limitation I could not afford Scan-Speak or similar drivers. So please reply keeping this point in mind as sell. Let me tell you that my budget is 25K (max including cabinets). I could stretch the budget till another 10-20% in extreme conditions considering price+performance ratio.

Last but not the least - please forgive my limited knowledge in this field and thanks everyone for bearing with me and providing their time and support.

 

[tcpip]

As I live in a small apartment, I won't be having too much space left from the back of the speaker and wall. So it would be better If I could design a TL with the open end at the front.
To be very honest, I did not understand the quarter-wave theory properly. But I believe guys like you are always here to educate me. I am counting on you (and everyone else as well).

BTW... my preferred cabinet dimensions (external dimensions)
Height: 36" - 42"
Width: 7" - 8"
Depth: Anything less than 20"

This is a classic Indian scenario. We all live in small apartments.

Brings up my pet idea -- why don't you think of a wall-mounted speaker design, with a bass reflex port firing downwards? The Peerless India drivers will be good enough to deliver decent SQ on your budget. Don't go for veneer and expensive varnish/polish --- go for laminates for the cabinet. This will keep costs under control. A simple 2-way or an MTM (which is 2-way too) will be perfect.

Does anyone else have any ideas about this approach?

 

[kapvin]

First, I am awefully sorry that I couldn't take a look at the suggestion/articles you've shared as I was out of town.

Thank you everyone for your time.



@doors666... thanks a lot for your valuable suggestions.



@kapvin... my objective is to build a pair of floorstanders. My room size is 13.5'X9.5'. A pair of bookshelves might be sufficient enough for my room but I am always fascinated by the looks of tower speakers.

The reason why I was inclined to TL over bass reflex is - I found through my initial reading that TLs produce more clarity over midranges (please correct me if I am wrong). As I already have a dedicated sub and intend to upgrade the sub sometime next year, I need the midranges loud and clear.



That's an awesome offer I can't refuse . Could you please share any sketch with me whenever you have time. I am in no hurry. Thanks a lot for the offer.



As I live in a small apartment, I won't be having too much space left from the back of the speaker and wall. So it would be better If I could design a TL with the open end at the front.
To be very honest, I did not understand the quarter-wave theory properly. But I believe guys like you are always here to educate me. I am counting on you (and everyone else as well).

BTW... my preferred cabinet dimensions (external dimensions)
Height: 36" - 42"
Width: 7" - 8"
Depth: Anything less than 20"



I believe I am not stubborn. I am ready to accept any design that might sound better. I am open to suggestions here. I am open for TL or Bass Reflex or Sealed or anything else. SQ is the top priority.




@ghatgepatil... these are awesome articles worth reading. Thanks for sharing the same.

As my preference is 2-way or 2.5-way, I liked the following design as this one has open port at the front:
Article: http://www.kt.agh.edu.pl/~natkanie/papers/TLS.pdf
Page: 4
Fig. 8
Third from the left.




@tcpip.... I've come across the site fortunately. But as I've stated above, I could not understand the theory properly.


To All,
I was considering the TriTrix design because I had a chance to bring those drivers from US and I don't have to take the pain of determining crossover components by myself. Looking the current scenario, I think I won't be having that opportunity and have to procure the drivers/parts locally.

So I was giving a second thought to go for Peerless drivers and building the crossover from scratch. Please suggest whether that's a good idea (!!??)

Please consider that due to my budget limitation I could not afford Scan-Speak or similar drivers. So please reply keeping this point in mind as sell. Let me tell you that my budget is 25K (max including cabinets). I could stretch the budget till another 10-20% in extreme conditions considering price+performance ratio.

Last but not the least - please forgive my limited knowledge in this field and thanks everyone for bearing with me and providing their time and support.

it's always better to start with a kit. and with a well regarded kit there is also the thing that your initial reference on "good sound" matches that that of a lot of others, incl people who know their sounds.

I will be happy to design a TL / MLTL enclosure for a given driver on a FOC basis.

But excl cabinets, I'd aim a bit higher. I'd look at the modula Mt or Natalie P designs on the HT forum as good candidates. (and easily worked into a TL I am extremely familar with that woofer (RS180) and cannot praise the driver enough. (i have used it in my car, HT and one upcoming standalone design). it can go really deep and is amazingly clean in the passband. the tweeter is also good. cost of (w+t)x2 = 200 dollars. if you want to save on the crossover you can look at the Core2. (not as clean- but still very good). within the same heght and width limits and about 70% of the depth you can get extension upto 30hz effortlessly.

but what are your sound goals. still not clear.
:-_

 

[ghatgepatil]

Too many DIY efforts showing up on the Forum front page . Its going to give the branded retailers many sleepless nights!

 

[tcpip]

it's always better to start with a kit. and with a well regarded kit there is also the thing that your initial reference on "good sound" matches that that of a lot of others, incl people who know their sounds.

Absolutely agree, provided Saikat is okay with the physical dimensions, etc, of the kit enclosure. Most kits have crossovers designed for free-standing placement. Hope Saikat is comfortable with one of the JonMarsh designs free-standing on the floor in his room.

If Saikat wants to place the speakers close to the wall, he may need to tweak the BSC or else he may land up with over-strong bass.