My head is swimming

[cameronthorne]

Hi folks. I have been lurking here for a while, and I just wanted to post a brief introduction. I am interested in DIY audio projects and understand some of the theory, but I don't have much real experience yet. I have no woodworking experience, but I do have coworkers with garage workshops who can help out in that area.

Anyway, my head is swimming trying to wade through the Mission Accomplished threads! There are about a dozen designs, each with several crossover options, and ~500 posts each! :E

I am interested in the following designs. Can anyone give me the 25000 foot overview of how they differ from each other? Roughly what price range does each fall into for parts costs, including cabinets? I understand that there is a pretty wide range for each. What is the bass response like; where could they be crossed over to a sub?

Dayton RS WTMW / TMWW
CJD MTM RS150/27TDFC/TV
NatalieP
Dayton RS 3-way towers
Modula MTM 1 / Modula MTM Center
RS180 Modula MT
Extreme MT

Bass Bins for any MTM

-- Cameron

[ThomasW]

Surely you aren't interested in everyone of these designs. I mean were taking about everything from small MT to a huge WWMTM tower.

Component costs are listed in the design threads. Cabinet costs are completely up to you and your choice of materials and finishes.

The Modula MTM and the NatP are the same speaker, the only difference in the NatP has a cheaper crossover.

If you use the forum's search function you'll find several threads about bass bins.

What you might want to do is decide is what size speaker you want or need, then read the appropriate threads. Almost all the threads have the bulk of the pertinent information encapsulated in the very first post in the thread.

[cameronthorne]

Thanks Thomas.

I would actually simultaneously consider both a WWMTM and an MT, for different locations in a complete surround system: Mains, Center, Surrounds. I'm starting from nothing.

I'll go digging around the first posts and pull up the BOMs and see if I can find the information I am looking for; I was just hoping there was a sort of overview thread for those of us who are late to the game.

-- Cameron

[Dennis H]

Short version: the bigger speakers play louder, cost more and are, errrr... bigger.

[Brian Bunge]

The biggest questions are, how big is your room and how loud do you want to play!

[cgr]

Can you say Analysis Paralysis?

I've built a pair of Modula MTs and have been happy with them. I'm currently building one of CJD's rs150 mtm to use as a center channel. I suspect that at one point I will build a dedicated center channel and a mate for the mtm.

Comparing the Modula MT with CJD's design the costs are pretty close to each other. The Modula has one less driver but the inductors are much less expensive(If I recall correctly the largest inductor cost more than the RS180).

If you're like most people you probably won't stop at one project. The crossover for CJD's design went together for me in much less time as the Modula MT; but that is partially because of the experience I had building the Modula crossovers. That said there is something to be said for starting with an attainable goal. My first project was a sub so that I wouldn't have to deal with crossovers. Any of the designs that you mention can be integrated with a sub well.

It might be worth mocking up with cardboard the cabinet sizes to see how they might fit in your environment. CJD's mtm is 2.5" narrower than the Modula, but deeper(at least the ported design).

These are just my thoughts as an assembler whose been through a couple of projects...

[cameronthorne]

Next steps...

Well here goes nothing. Analysis paralysis is right. I am the type that doesn't like to do something at all until I can do it right the first time. Because of that, I've been listening to nothing but my TV speakers because a proper surround system has been beyond my financial reach. I've been reading everything I can get my hands on, and I've heard a fair number of commercial speakers. I have been saving up for almost two years to build 5 Linkwitz PLUTOs and some sort of sub. I am now ready to proceed, but since then I've learned a lot. The tentative plan has now become: 3 PLUTO speakers, 2 PLUTO+ speakers and a Rythmik Servo 15" sub (sealed in an end table). (Infinite Baffle and giant water heater EBS were both nixed by my wife.) With the idea that maybe I'll build the ORIONs to catapult the system to 7.1 some day, but probably not until we move to a different house. (I'm not looking to discuss or promote SL's kit designs in this thread - I know that is off limits for this board).

So...what brings me here? I am open minded to other possibilities, particularly if they will improve WAF or decrease the money required to build this entire system from scratch. I do not have the expertise required to design my own speaker system (yet), but I am decidedly going down the DIY path - I will definitely "assemble" whatever I end up with myself, but use someone else's design. I want to have some fun doing this. I already have some parts for the PLUTOs, but I could sell them in theory.

So...some details. This is for my living room. The living room is about 14' x 21' x 10'H, or 3000 cu.ft. One corner of the room (part of two walls) is completely open to the kitchen and breakfast area, which adds another 2000 cu.ft. There is an open archway to the dining room, foyer and hallway, which is another 2000 cu.ft.! So the room itself is 3000 cu.ft., but there is about 7000 cu.ft. of total connected space. See pictures of the room here. The TV will have a slide-out swivel shelf built in to the bottom of those built-ins, so my "sweet spot" will technically be the smaller couch in the middle of the room, on a diagonal. Thus, the system will run along the diagonal of the room. This is non-negotiable until my kids are older. :

One thing I liked about the PLUTOs was their relatively small footprint, and their lack of woodworking/finishing skills required. The general design philosophy that Dr. Linkwitz takes is something that I have found myself subscribing to in theory. The physical speakers themselves are pretty inexpensive, so if my kids knocks one over and damages something, it isn't quite as serious as it could be. Fixing PVC pipe is not hard. I would try to modify the physical look of it slightly to improve WAF.

I will use this for music more often than movies, but movies are equally important. In my auditions of commercial speakers, I have found that I like a "critically damped" bass response.

So I'm left full of questions. So considering that a 5.1 system based on PLUTO and Rythmik would cost me around $5000, what alternatives should I consider here? Is uniform polar response really as important as SL makes it out to be, especially in troublesome rooms? Will I be happy with normal "box" speakers? Most of the designs I see in the Mission Accomplished forums have very large footprints - they are very deep boxes. Mocking them up in cardboard is a good idea. I don't know that I have the space for something like that. I do not have room for 7.1 in this house, so 5.1 it must be. What about dipoles?

Anyway, I am full of questions and open to any possibility, but I'm ready to go at this point. If I am to change course, I need to decide now. I have tried to explain my requirements, preferences and reasoning behind my current "plan" above. Do any of you have any general comments for me to consider or suggestions of things to consider about HTGuide designs?

Thanks as always. Thomas et. al. has always been very helpful with my n00b questions here and on several other forums. :T

-- Cameron

[Al Garay]

So, what are your motivations for DIY?

$5k is a sizable budget for 5.1 speakers and sub. You can look at complete options such as:

Rick Craig - Selah Audio's latest custom HT system

http://www.audiocircle.com/circles/index.php?topic=36386.0

Phil Bamberg - BESL Labs Series 2.5 LCR for front 3 and Series 2 MT for surrounds

http://www.bamberglab.com/s25lcr.shtml

http://www.bamberglab.com/s2mt.shtml

or get the Series 2 MTM x 5 kits which are on sale for $585 a pair

http://www.bamberglab.com/sale_items_feb07.shtml

Al Wooley Raw Acoustics HT8 kits on sale for $799 a pair, 2 pairs plus the Apex Center kit would be under $4k, leave you enough for his SD2P subwoofer.

http://www.rawacoustics.com/index.php

There are many options. You should call and talk with these designers to help you figure out your needs.

[ThomasW]

Since one can buy just the plans and PCBs, discussion of Siegfried's designs aren't off limits on this board.

I think the Plutos are cute, but you've got a BIG space to fill with sound. .

$5K for a 5.1 system constisting of 5" 'woofers' IMO is a bit much.

IMO, your room and the adjacent areas are too large for the Plutos.

The 'footprint' of the Pluto is no bigger any most minitower speakers. And most women I know would rather look at a nice piece of finely finished wood, rather that a bizarre periscope made form PVC. (not don't get me wrong, I think the Plutos are cool looking. But I can't imagine them getting the SAF seal of approval)

[cameronthorne]

I am attracted to DIY in general for several reasons.

I have built a few pieces of crude "furniture" over the years, and immensely enjoy working with tools and materials (including wood). There is a huge sense of satisfaction when you sit down with a piece of paper and a pencil one day, and a few weeks later you have a finished piece of furniture that is immensely functional and suits your needs perfectly. That said, I do not have many woodworking tools currently. That would add indirectly to my project, and would have to come out of the $4-5K I have to work with. I do have a friend with a woodworking workshop who is willing to help since the PLUTOs involve so little wood, but I think I would be overextending my welcome if I asked him to help me with six wood cabinets with fancy veneer.

Also, I love to learn new things. Every DIY project is a little bit different, and there is something new to try that you have never done before. DIY is about learning. I can enjoy the process every bit as much as I will enjoy the use of whatever I make. I can't say the same thing about the process of shopping for store-bought goods. I am interested in crossovers and electronics and psychoacoustics and codecs and the whole bit. I like to learn, and I want to get my feet at least ankle-deep in a project that exposes me to some very new things.

In defense of the PLUTO, technically the PLUTO+ is a 3-way and has a 10" woofer as well as a 5" midrange. Though you are right, these would probably not be good past -15 dB on the volume control - certainly not reference level. They are intended to be somewhat near-field. I doubt I would be doing very much listening at reference level even if I had the capability. Regarding footprint, the base of the PLUTO can be made quite a bit smaller than SL's standard design, and even as is it is 23% smaller than even the Modula MT in a standard PE box. This was part of the appeal for me. The ability to shove these out of the way when my kids want to run around was a big plus for me. SAF is a pretty major concern on anything made from PVC in a living room, but I was prepared to get creative on the design to maximize SAF. The last thing my wife wants is a large rectangular coffin standing in the room, regardless of how nice the finish on the wood is; she would prefer the PVC. Smallish MTs or MTMs on stands would probably be acceptable. Maybe the Extreme MT project is something I should consider.

So what do you think specifically about some of these questions:

Is uniform polar power response really as important as SL makes it out to be, especially in troublesome rooms?

Are there any open baffle or omnidirectional designs that are at some reasonable stage of completion for the DIYer in this price range that I should be considering?

Why are so many of the HTGuide designs ported? I thought ports did some not-spectacular things to group delay, and were completely useless below tuning?

Has anyone made a dipole/tripole surround design for the DIYer? What are the issues associated with listening in a dipole null in an open room where the dipole would not be wall-mounted?

Obviously I am still learning about all this stuff. For box-type speakers, I like the looks of Aerial Acoustics, B&W, Dynaudio, etc. I.e. narrow, tall baffles. I seriously doubt my personal ability to recreate a look like that without expensive veneers, stains and finishes, something I have no experience with. However, it seems like with proper thought, equipment and experience, many of the HTGuide designs could be made to look that good.

I guess I have a lot to think about. Could $4-5K get me all the tools I need for proper woodworking, WWMT towers or better, WMTW center, two MT surrounds, stands and a sub?

-- Cameron

[ThomasW]

Regarding footprint, the base of the PLUTO can be made quite a bit smaller than SL's standard design, and even as is it is 23% smaller than even the Modula MT in a standard PE box.

Not if you count the box for the woofer

Is uniform polar power response really as important as SL makes it out to be, especially in troublesome rooms?

It's obviously important to him. Doesn't seem to be a big deal to others since they're not duplicating his designs.

Are there any open baffle or omnidirectional designs that are at some reasonable stage of completion for the DIYer in this price range that I should be considering?

None with a footprint as small as you want

Why are so many of the HTGuide designs ported?

Because that's a choice the designer made. It's no big deal to build them sealed.

I thought ports did some not-spectacular things to group delay, and were completely useless below tuning?

There's a trade off for every design choice. Ports are no exception

Has anyone made a dipole/tripole surround design for the DIYer?

What's a tripole?

What are the issues associated with listening in a dipole null in an open room where the dipole would not be wall-mounted?

Beats me...... :B

[JonMarsh]

So what do you think specifically about some of these questions:

Is uniform polar power response really as important as SL makes it out to be, especially in troublesome rooms?


-- Cameron

Uniform power response (on axis versus off axis) is very important in any room because much of the sound you hear in a normal listening room is not direct sound, but reflected indirect sound, and if the spectral balance is off, the ear knows this.

A much bigger problem is that many room/speaker setups have FAR TOO MUCH early arrival indirect sound which creates comb filtering in the primary axial frequency response, and destroys imaging cues. Based on psyhoacoustics, indirect sound should be coming with 20 msec + delays, and from the side and rear to the opposite ear of that receiving the direct sound. Splashing stuff all around near the front of the room doesn't do that to well, obviously.

Why are so many of the HTGuide designs ported? I thought ports did some not-spectacular things to group delay, and were completely useless below tuning?


-- Cameron

Reflected bass waves from typical home speaker placement do some VERY ugly things to frequency response and modal excitation in a room- much more than a properly desiged ported enclosure. A well designed ported enclosure can allow more low frequency extension at higher SPL for a given driver and box combination. Below the port tuning, the driver won't respond well. Do you expect 7" drivers to respond well to 20 Hz anyway?

Designs like the Modula MT and Modula MTM have useful strong output which is at a balanced level in the room with an anechoic downslope of 6 dB to the box Fb, so the in room response correctly placed is quite smooth.

Has anyone made a dipole/tripole surround design for the DIYer? What are the issues associated with listening in a dipole null in an open room where the dipole would not be wall-mounted?


-- Cameron

Open back diople loudspeakers have controlled directivity to avoid exciting room nodes and generating early delayed arrivals. You wouldn't listen to a dipole speaker in the side null anymore than you'd listen to a horn loudspeaker behind the system- or headphones wrapped around your butt.

If you like a diffuse "sound is everywhere" reproduction with a strong imprint of the acoustics of your listening room, then a dipole is not for you. A diople system is for reproducing the original recording and it's acoustic venue as clearly as possible with as little interference as possible from the playback room.

Two words. Controlled Directivity.


~Jon

[BigJim_inFLA]

I guess I have a lot to think about. Could $4-5K get me all the tools I need for proper woodworking, WWMT towers or better, WMTW center, two MT surrounds, stands and a sub?

Absolutely! You can make very nice speakers with very little in the way of tools. I live and build my speakers in a 850sq ft 1 bedroom apartment. I do most of the dusty work on a 5' x 9' patio. I use only a router, drill, jig saw, and circular saw w/ sawboard. You can even get away without the circular saw if you want. I have had the guys at HD or Lowe's precut my peices on their panel saw, just know that they won't be exact, but usually close enough. If you already have basic hand tools you could get decent quality power tools needed for speaker building for about $500.

Here's what you can do with very limited tools:
WMTW Center
My TMWW
My Nat P's

It just takes a little more time than if I had a shop with all the tools I could want. It also clutters up my living room, but I live alone so it's OK. :T

[cjd]

You can build high quality basic speaker boxes with no more than a good router + flush-trim, spiral upcut, and round-over or chamfer bits as needed, and a circular saw + sawboard. And lotsa good clamps.

[cameronthorne]

Tripole is just a non-scientific term that I use to describe wall-mount surround speaker designs that combine direct radiating with dipole operation. Say, direct-radiating MT with WW in dipole operation to the sides. Dipole surrounds were advocated during the Pro Logic era, and some continue to advocate there use today for the side surrounds in 7.1. Is all that listening in the dipole null stuff rubbish? Is "diffuse" sound simply asking for room coloration trouble?

Thanks for all the suggestions guys. ;x(

After sleeping on it I have taken a step back from the "analysis paralysis" :unsure: and come to a few conclusions.

1. I will most likely be happy with whatever I build, be it PLUTO, ORION, Isiris, Modula MT, Dayton RS WWMT, active or passive. I think the output capabilities of all of these will suit my needs in the short term. But what about the long term? See next point...
2. I know that this will not be my last project. This is just the beginning. Once I have at least a base system set up and the tools of the trade so to speak, I am free to make changes as funds allow. And I will. To me, this is as much about learning as it is about the sound.

Ergo, I should just let my wife decide which designs she likes best (dislikes the least?) to maximize SAF, and then get started on round one.

Whew! I feel better now. :T

-- Cameron

[BigJim_inFLA]

1. I will most likely be happy with whatever I build, be it PLUTO, ORION, Isiris, Modula MT, Dayton RS WWMT, active or passive. I think the output capabilities of all of these will suit my needs in the short term. But what about the long term? See next point...
2. I know that this will not be my last project. This is just the beginning. Once I have at least a base system set up and the tools of the trade so to speak, I am free to make changes as funds allow. And I will. To me, this is as much about learning as it is about the sound.

Ergo, I should just let my wife decide which designs she likes best (dislikes the least?) to maximize SAF, and then get started on round one.

Whew! I feel better now. :T

-- Cameron

I would suggest starting with something small and relatively easy to build. The Modula MT was the first project I built after my sub. It's small and uncomplicated box is pretty easy even with limited tools. You could build a pair and use them in 2channel as mains to see how you like them. If they meet the wife's approval and sound good (which they do) you could build more and complete a 5.1 or 7.1 system. If you feel you need more bass or SPL, just build Modula MTM or the TMWW and move the Modula MT to surround duty. Nothing wasted and an easier start than jumping right into a larger, more complicated design with more difficult crossover and box construction and much higher expense.

Jim