BAMTM For A Clueless/HT-Less Guy

[chibahawk]

Right now I'm watching a movie (Snatch) on a 50" rear projected LCD Sony. It looks good. However my current HT if you want to call it that is a relic from when I knew nothing about tech - it's some 5.1 Sony DVD receiver and it's time to get rid of it.

For starters - What is MTM? I haven't found anything in the HT Dictionary and searching hasn't really helped me out.


I think Zaph's BAMTM design would be great for me and is a great idea of my budget (cheap!) and experience (none!).

In any case I don't have many questions regarding the project yet because it'll be a week or two before I have the parts, but I do have a good question.

What should I look for in a receiver regarding power output? I don't plan on going with satellites but may certainly get a subwoofer in the future. I saw someone worrying about the ohm load of the BAMTM and just don't want to buy a receiver that will suit the Zaph project and not have any room for future upgrades.


Thanks!

[---k---]

MTM is a description of the layout of the speaker drivers. It means: Mid/Tweeter/Mid in a vertical arrangement. Good power handling and dynamics. Better on axis, poorer off-axis. very popular.

It sounds like you're budget challenged. I would recommend a Pioneer 1016tx receiver. It is a good, solid well built <$500 receiver. Not necessarily cheep, but a good compromise between it and a lot of the more expensive ones.

[chibahawk]

Main difference between the 1016tx and Pioneer's entry level? Would it just be the HDMI input?



Also I'm realizing I should actually be asking questions about other designs instead of focusing on this one.

I'm basically looking for a design that has good sound and covers all the bases. I'd like a project that would eliminate the need for a center channel, possibly two towers that have nice bass as well.

[fjhuerta]

I also got started with one of Zaph's design. Trust him - he really, really does know what he's talking about. You should try reading through his designs - that'll help you get started.

Although, if you need to know what you are doing, , may I suggest the Loudspeaker Design Cookbook by Vance Dickason? You won't regret it!

[joecarrow]

I've just got to mention the Panasonic SA-XR55 and SA-XR57 receivers, the first of which is available new for about $200. In my opinion the sound quality is very nice, the features are decent, and it was the best $230 I spent on my home theater. It doesn't intimidate my girlfriend, and with the Modula MT speakers it goes plenty loud for me.

It's operates solidly with 6 ohm loads, with no reports (that I've heard) of trouble with 4 ohms. There's a neat feature where the front L and R channels will grab an one of the unused rear channels for extra help on amplification. They call it dual-amping, and it's really just running two channels of amp in parallel to power one speaker. This allows lower impedance loads and provides more current. An added benefit of this receiver is that it uses less power, is smaller, weighs less, and produces less heat.

Some folks might scoff at the suggestion, but I tell you that it sounds darned good, and I like the thing a lot for what it cost.

Also, part of the decision of what speakers to use should come from your room. How large is your room, how far away do you listen, how loud do you like it? Where can you put the speakers- away from the wall a bit?

[Hdale85]

Well the 1016TX Is a very nice receiver. It has a huge following as it started with the 1014TX which was said to be the same as their low end Elite receiver. I don't remember anyone ever confirming this though. It is very well built and has tons of features for a receiver of its price and quality. I'm not sure about the Panasonic though. It's a "digital" receiver thats what they call it anyways. Very small amount of space it takes up though.

I was thinking of the Pioneer but then went with a Yamaha RX-V2400 I got off audiogon at a very good price! If your will to go used (mine looked BRAND new) you can usually find some good deals as mine retailed for 1000 bucks. Just up to you

[chibahawk]

Also, part of the decision of what speakers to use should come from your room. How large is your room, how far away do you listen, how loud do you like it? Where can you put the speakers- away from the wall a bit?

I'm definitely goin to look into that receiver.. that's cheaper then even I thought I would be able to find one. My basement is the room it's about 13x17 the area that will dedicated to HT. Listening distance at about 11ft. and I can definitely have the speakers a foot off the back wall and over 3 from the sides.


I'm going to check out audiogon too I think but it's a little intimadting unless you know what you're looking for I guess - which is why suggestions are definitely appreciated.


Thanks for now - gotta back to finals!

[joecarrow]

That's not a huge room, and thats not terribly far to listen. I think that the 100 watts the Panasonic is capable of will be sufficient, especially with an MTM based design. Yeah you can do better than the Panasonic, but I feel that you'd have to spend at least double to get a noticeable improvement.

In my experience it sounds great, and the flexibility of the built-in filters (crossing to the sub at 80, 100, 150, or 200 hz) was really nice. They could have probably given you even more choices and control, but a lot of consumers would get confused.

I'm also a proponent of used equipment- even more so for amplifiers and electronics. It's just my prejudice, but I think that speakers suffer more and degrade when they are abused, and the electronics such as equalizers, receivers, and amps are more likely to outright break.

[chibahawk]

That's not a huge room, and thats not terribly far to listen. I think that the 100 watts the Panasonic is capable of will be sufficient, especially with an MTM based design. Yeah you can do better than the Panasonic, but I feel that you'd have to spend at least double to get a noticeable improvement.

In my experience it sounds great, and the flexibility of the built-in filters (crossing to the sub at 80, 100, 150, or 200 hz) was really nice. They could have probably given you even more choices and control, but a lot of consumers would get confused.

I'm also a proponent of used equipment- even more so for amplifiers and electronics. It's just my prejudice, but I think that speakers suffer more and degrade when they are abused, and the electronics such as equalizers, receivers, and amps are more likely to outright break.

so how much are you sellin for :P

Yeah im definitely going to look into it.. I'm thinking my best thing to do is look into what drivers I want to make first then fit a receiver in last seeing as I don't actually have to build it

So as of now I'm thinking 3 BAMTM and one cheapish Pio receiver. I just have to make some kind of cabinet design that will let me have the center channel vertical.




Question::: Would it be a good idea to make the center channel the 2cu.ft vented enclosure instead of the 1cu.ft sealed? In my mind I'm thinking the center channel handles more of the bass but then again I know close to nothing.

[joecarrow]

I'm not selling anything! Actually, I'm kind of trying to get rid of a black 0.38 cu ft Parts Express cabinet, but that has nothing to do with this.

It's not a bad idea to pick the speakers first. Keep in mind that all of the established projects out there are counting on the front of the speaker being the same width as in the original design, and the arrangement of the drivers being the same. The crossovers around here are sophisticated enough that they take these things into account, and sound significantly better for it.

Also keep in mind that the BAMTM is not intended to be on its side, so you're probably going to have a hard time getting it to work with a standard TV as a center channel. A projector with a transparent screen would give you no trouble, but a traditional screen is going to require that the tweeter is way above or below the screen.

Regarding your question for the center channel- no, the center is generally (as far as I know- I don't use one right now) for dialog, and helps anchor the sounds that are suppose to be "front and center" right at the screen. You could honestly build the left, right, and center as all sealed if you have a high quality subwoofer. You'd just need to ensure that your receiver can run them in 'small' mode.

I'd say that the key thing to concentrate on for a center channel is good midrange- also good sound from a wide angle, we call this wide dispersion.

[DS-21]

I'm not sure about the Panasonic though. It's a "digital" receiver thats what they call it anyways. Very small amount of space it takes up though.

The Panasonic XR-series receivers use a very cool amp technology that converts PCM audio signals directly to PWM signals for the amp, without the intermediate D/A conversion stage that all other "digital" amp designs seem to use. It's a commoditized version of the technology pioneered on the high-buck TacT stuff.

Like joecarrow, I use one in my main system, and until somebody comes out with something in a similar form factor with similar energy efficiency and good room correction software built in it will be staying there.

[joecarrow]

I hear that, DS- another 5 years and there's no way we won't be able to have insane digital room correction in a package of this size and cost. The technology's definitely not 5 years off, but I give it at least that long before it gets cheap enough that it will be a no-brainer to add it to something is such a low price bracket.

Seriously, most people don't know what they're missing with what they presently listen to. Sure, the regulars here have a pretty good idea of the gap between their gear and a live performance, but the average Joe doesn't.

Actually, my attitude in this post reminds me of an old joke. It goes like this:

An Audiophile is walking down the road when he sees someone on a park bench listening to some music on a beat up, crummy, dented cassette tape deck with one working speaker, with the sound badly distorted by the cassette, the tape, and everything else. The Audiophile is aghast and asks, "Sir, what is that you're listening to?"

In reply, the man looks at the Audiophile like he's crazy and says, "Beethoven."

[chibahawk]

well yea im going to have to put the center channel vertical i noticed they wouldnt perform the same off axis i think you would say.

the way my basement is i can hang the center above the tv or plant it below. the right and left channels will be 12" above the center so would there be any negative effects of not having them on the same level?

[chibahawk]

quickie- im about to buy the parts for my project.

can someone just check this out for me.

27TBFC/G tweeter x 3 @ 32.80 - 98.4
Zalytron

da175-8 dayyon x 6 @ 16.60 - 99.6
PartsExpress

x-over x 3 @ 21.5 - 64.5
??? - Zalytron?
L2 - 1.80 mH .47 ohm Sidewinder 16AWG $12.50 ea
C4 - 31 uF Bennic Electrolytic $1.10
R6 - 7 ohm Eagle Metal Oxide Film non-inductive $1.20 ea
C7 - 10 uF Bennic Metallized Poly $3.75
L8 - .30 mH .2 ohm MB Standard 19ga $2.95 ea



Also I should get some AcoustiStuff or something like that? How much would I need also. And is there anything else I may need?

Thanks

[augerpro]

I think Madisound has those TDFC's onsale. And they carry those XO parts as well I beleive.

[chibahawk]

I think Madisound has those TDFC's onsale. And they carry those XO parts as well I beleive.

i had actually checked them first and they were a bit more I think on Madisound plus Zalyton is only like 30 minutes away if even.

[joecarrow]

Some sort of binding posts are nice, as well as flared ports- although I realize this is a budget project. You really can use straight tubes for ports, they just won't go as loud without making port noise. You can also run the wires out through the ports, and not use speaker terminals. That's a fast way to save at least $10, although I really feel better with the convenience of terminals on the back of the speaker.

Acoustic-stuff is good to have, and people will probably tell me that the poly-fill stuffing I get at Wal-Mart isn't worth a darn... but it sure is cheap for a huge bag. Only use that if you're going sealed. Otherwise, scraps of carpet padding or fiberglass batting should help out the inside surface of your cabinet.

Also, since you have a nice TV, people don't need to knwo that your speakers were a bargain. If the drivers are going to be exposed, you might as well do something for looks and get some nice-ish screws.

[Raptor550]

Some might say this is Hi-Fi heresy but if you are a computer guy: some old stereo amps have really low noise floors and good power. for the price of a new pioneer you could buy 3 vintage ones (pioneer SA-8800 for example). Have one for center & sub and then the other 2 for mains and rears. Hook it all up to a sound card and use the computer for volume, computers can download neo6 and dts and all that stuff for dvd's. As an added bonus everything is shiny looking!

It works well, I'm using 2 kenwoods.

I haven't heard the BAMTM's but after the speakers I built (see below) I bet they are killer for what they cost. They will probably be my next project

[cgr]

I hear that, DS- another 5 years and there's no way we won't be able to have insane digital room correction in a package of this size and cost. The technology's definitely not 5 years off, but I give it at least that long before it gets cheap enough that it will be a no-brainer to add it to something is such a low price bracket.

I see alot more equipment that come with a mic to do the room correction at setup time. How well does this usually do this? Just curious if anyone has done this and compared the results to setting each channel with test tones individually?

[Hdale85]

It depends a lot on the receiver I believe although I think most do a decent job. My yammy has auto room eq and correction stuff and thats how I set it up and it sounds great to me :B

[Gir]

It depends a lot on the receiver I believe although I think most do a decent job. My yammy has auto room eq and correction stuff and thats how I set it up and it sounds great to me :B

I have an RXV661, and the auto eq really sucks if you don't have a sub yet. Regardless of how I had it set up in the options, it always rolled off my speakers really early as though it were going to a sub. Once I get my sub I'm sure it will be a lot better. As for right now I just have a pair of Mark K's RS225/RS28A

[chibahawk]

I've got a question regarding the placement of the drivers - I'll be building an entertainment center so I can kind of address the issue about placing a center channel driver horizontally. My question is this:

Would I be better off placing the L&R Channels on the L&R side of the TV about 24" off the ground and then placing the Center channel on the ground under the TV?

Or Should I place all 3 channels on the ground and try to point them upwards just slightly?

And if there would be very little difference or if the placement isn't something that would bother the casual listener please let me know - thanks.

[chibahawk]

Ordering Parts for Drivers. Input please...

I'm new to the game and I'm just looking for suggestions on anything I could be overlooking.

I just ordered the parts for the BAMTM drivers (Making 3 of them.) So aside from what's on Zaph's audio site - what else might I need?

I did order some acoust-stuff for the sealed drivers, and 3 terminal plates.

What kind of speaker wire? Can I just get the basic 16awg from home depot? And what % solder should I use?

Anything else please add on
Thanks

[chibahawk]

Another question... I have a connection to get Sony receivers at cost. Is ANY of there stuff in the audio world worth their weight?

[Brian Bunge]

The ES stuff is supposed to be pretty good. Otherwise, the only way I would own one is if you gave it to me. I'm just not a fan of Sony's entry level stuff. I'd rather have Pioneer.

[ThomasW]

I second Brian's suggesting regarding the ES line of Sony electronics.

Regarding solder, if you have VERY high-end electronics you might be able to hear the differences solder makes. I have some pretty hot sh*t/very $pendy electronics and can't hear any difference in solders.

I think you'll be fine using any brand name standard electrical solder. Kester and Multi-Core both make excellent solders.

If you want idiot proof solder then go with Cardas quad-eutectic, but don't pass out when you see the price... 8O

Yes 16 gauge wire is fine for wiring the internals of the speaker. It might be a bit too big for the tweeter.

[chibahawk]

I second Brian's suggesting regarding the ES line of Sony electronics.

Yes 16 gauge wire is fine for wiring the internals of the speaker. It might be a bit too big for the tweeter.

I'm definitely going to see how cheap I can get the ES line of Sony stuff. If I don't do that I will probably go with the Onkyo I've been eyeing. (TX-SR674)

As for 16awg on the tweeters I may just trim off some threads. I know - not what installation enthusiasts recommend but if it does the job..
---Regarding tweeters, the person who took my order mentioned that I should be careful when soldering them, but I don't remember why? Less room to work with maybe?

[ThomasW]

Regarding tweeters, the person who took my order mentioned that I should be careful when soldering them, but I don't remember why? Less room to work with maybe?

The lead wires on tweeters are thinner than a human hair. If a thick wire is soldered onto terminal it's easy to snap it off and trash the dome.

[chibahawk]

The lead wires on tweeters are thinner than a human hair. If a thick wire is soldered onto terminal it's easy to snap it off and trash the dome.

So it's just important not to flex anything around that area as when its soldered on it could snap? I figured it was just a question of size and caution.