Polk Audio Monitor 60 VS MTM design with W5-704D and DX25TG

[mintos]

I was trying to figure out if I can build a set of decent towers that can preform better than the Monitor 60 at 120 per pair (no tax, free shipping)

Closest I've seen is the MTM desing with
264-578 Yes Vifa DX25TG-05-04 1" Fabric Dome Tweeter

264-850 Yes Tang Band W5-704D 5-1/4" Woofer

Speakers with crossover cost $123.30. I figure the cabinet stuff will cost another $25.

Will the 150 MTM sound better than the Monitor 60? It's looking like a great deal atm.

[ThomasW]

Might want to recheck the price on the Polks. Most places are listing single speakers for $130.

http://www.newegg.com/Product/Product.aspx?Item=N82E16882290017

[mintos]

Sorry I ment $120 per tower. There's a coupon code for $10 off.

[---k---]

When I listened to CJD's RS150 MTM in my home versus a pair of: $1400 Paradigm Studio 40s, $800 DynAudio 42s, and $550 Ascend 340SEs, I clearly thought that CJD's were better. (And a year later asked CJD to design me my monster towers) So, yes DIY can provide much better speakers.

BUT, you must have the tools and desire to DIY. Most people end up not saving money by DIYing after all the tools and time and effort. But, it is fun and keeps us out of trouble. I really don't recommend DIY speakers to save money.

You might want to really consider the TriTrix design. It is in your budget and is very good. PE is also offering recesion buster kits and precut knock-down boxes for them now at an extremely reasonable price.
http://techtalk.parts-express.com/sh...d.php?t=209947 This is 1/2 way between DIY and retail. So a good intro.

[savage25xtreme]

not sure how the monitor 60s sound but, I have some Polk R30's and my BAMTMs destroy them in every way, shape, and form... but come in at about $300 a pair for build components

[mintos]

I saw the Trix too, looks good. 5.25" woofers are probally better for base though. I don't want huge towers. I want to build a MTM design with

260-142 Yes Dayton XO2W-2.5K 2-Way Crossover 2,500 Hz
$23.07 $23.07

264-578 Yes Vifa DX25TG-05-04 1" Fabric Dome Tweeter
$28.57 $28.57

264-850 Yes Tang Band W5-704D 5-1/4" Woofer
$24.70 $49.40

Subtotal: $101.04

I saw on this site a MTM design with those speakers. Only 22" long. I can probally for go some base for a smaller cabinet as I'll be using a sub.

http://www.htguide.com/forum/showthread.php4?t=28282

However, when I went to get individual components for the crossover, the price was not exactly what I wanted. I see that the prebuit crossover is cheaper, but ofcoarse it's not going to be optimum. I'll see if it can work out with a center horizontal MTM first, maybe tweak it a bit. If it sounds good, I'll buy 6 more for my new living room setup. Cost wise, the polk will probally still be better. However, I'll have some time come end of spring semester. So it'll be a good time killer.

[savage25xtreme]

you should avoid the pre-built cross overs like they are the plague. If you have the tools and time build something easy BAMTM or TriTrix or Nat P's..... if not get some Polks.... they will certainly make noise that may even be satisfying to you :B

[---k---]

you should avoid the pre-built cross overs like they are the plague. If you have the tools and time build something easy BAMTM or TriTrix or Nat P's..... if not get some Polks.... they will certainly make noise that may even be satisfying to you :B

Agreed.

The Polks will likely sound better than random drivers and a prebuilt crossover.

[mintos]

What's wrong with that pre-built crossover? It's a standard 2nd order LR filter. All the components look like quality and the 2500hz crossover point fits the speakers well. I just have to pick up some resistors for a L-Pad.

Otherwise the bill of materials look like this

004-4 Yes Dayton DNR-4.0 4 Ohm 10W Precision Audio Grade Resistor
$0.98 $5.88

027-422 Yes Dayton DMPC-4.7 4.7uF 250V Polypropylene Capacitor
$2.41 $2.41

027-430 Yes Dayton DMPC-12 12uF 250V Polypropylene Capacitor
$4.57 $4.57

027-436 Yes Dayton DMPC-20 20uF 250V Polypropylene Capacitor
$6.09 $6.09

027-440 Yes Dayton DMPC-30 30uF 250V Polypropylene Capacitor
$8.95 $8.95

027-450 Yes Dayton DFFC-0.01 0.01uF 400V By-Pass Capacitor
$0.74 $1.48

027-427 Yes Dayton DMPC-6.2 6.2uF 250V Polypropylene Capacitor
$2.66 $2.66

264-578 Yes Vifa DX25TG-05-04 1" Fabric Dome Tweeter
$28.57 $28.57

255-206 Yes Jantzen 0.15mH 18 AWG Air Core Inductor
$3.63 $3.63

264-850 Yes Tang Band W5-704D 5-1/4" Woofer
$24.70 $49.40

255-104 Yes Jantzen 1.5mH 15 AWG P-Core Inductor
$9.66 $9.66

Subtotal: $123.30

Plus another $25 or so for the cabinets.

[---k---]

There are so many posts here that explain why a pre-built crossover is not optimum that I'm not going to answer that.

[savage25xtreme]

the prebuilt crossovers do not take into account ANY of the following: baffle diffraction, step, mechanical and electrical properties of the drivers to mention a few. they are simply an electronic filter. what if you 2 drivers don't play to the same level? no notch filters or level adjusting resistors? take a look at the crossovers in the Missions Accomplished section of this forum. you will notice that few if any of them are as simple as the pre-builts, there is a reason. the crossover network is a function of drivers and the enclosure, not the other way around. :W

Do what you wish though and be sure to post the results :T

[mintos]

I bought the Polks, let me post some pics when they arrive ... jk

Actually, I get what everyone is saying. I don't see the pre-built XO as the end. But 2500hz is a good point for those two speakers. The response chart shows both speakers are very flat around it, and good enough for 2nd order. Thus, I'll use the prebuilt as a starting point. Once I finish modeling the cabinet, I'll build it and then modify the pre-built XO depending on the sound from the speakers in the cabinet.

[Undefinition]

There are so many posts here that explain why a pre-built crossover is not optimum that I'm not going to answer that.

:rofl:

Well, now that I think about it, your choice of drivers are excellent for a first design. They're both very easy to work with. The TB W5-704 has a very flat Frequency Response, and the Vifa DX25 has a very low Fs. Plus, the fact that you're running an MTM--assuming the woofers are parallel--means that you will suffer very little, if any, baffle step loss.

You could probably do such a design with a 1st order XO. I used the W5-704D with a 1st order XO in the Aethers, and lots of people seem to like those.

[Mudjock]

You may be new to this, so I can understand your position that a textbook filter should work if the drivers are similar in sensitivity. The first speaker I built started out that way (I eventually learned enough to fix it).

You might find the following thread helpful in showing how far off a textbook filter can be from what you really want.

http://www.htguide.com/forum/showthread.php4?t=31275

Given the frequency and impedance data for the W5-704D and DX25, it would be possible to give a reasonable simulation of what type of response curve a textbook LR2 filter would lead to - if you require further evidence that the off-the-shelf crossover is not the way to go.

I have heard the Tritrix and used the w5-704D (with a different tweeter than Augerpro) and based on that, I am confident that either design will easily surpass the sound quality of the Polks or any speaker that most people would consider "affordable".

[---k---]

Paul,
I was in a bad mood earlier. I should have pointed him to your FAQ's. Surprised you didn't.

http://undefinition.googlepages.com/diy-mfaq

[Undefinition]

Paul,
I was in a bad mood earlier. I should have pointed him to your FAQ's. Surprised you didn't.

Naw, don't feel bad. You just gave me a good belly laugh is all.

[mintos]

Does all textbook 2nd order crossovers need to have Tweeters in reversed polarity? (Seems like it, just want to double check)

[Face]

Does all textbook 2nd order crossovers need to have Tweeters in reversed polarity? (Seems like it, just want to double check)

Yes, the phase shift on a second-order crossover is 180 degrees(reversed polarity).

[Undefinition]

Does all textbook 2nd order crossovers need to have Tweeters in reversed polarity? (Seems like it, just want to double check)

Textbook, yes. However, very few speaker designs use textbook filters. When it comes to how a given filter and its component values affects the acoustic phase of a driver, you really need simulation software. There is a chance you could be 180 out of phase... or somewhere in-between. :E

My Girl From Ipanema design is basically a straight-up 2nd order (though still not textbook values), and as you can see the drivers are both wired positive, and the acoustic phase is extremely tight through the crossover region

http://undefinition.googlepages.com/diy-thegirlfromipanema

[mintos]

which software can I use for this?

[Undefinition]

which software can I use for this?

Good question. And the comforting answer is that it will cost you zero dollars to get started.

Some folks like Speaker Workshop (very versatile, but can get quirky to operate at times)

http://www.speakerworkshop.com/

Other folks (myself included) enjoy Jeff Bagby's Passive Crossover Designer

http://www.audio.claub.net/software/jbagby.html

... you will also want to grab Jeff's Response Modeler while you're there. This can help with doing box and baffle diffraction models, plus extracting minimum phase.

The rest of the gaps are filled in well by Roman

http://www.rjbaudio.com/Audiofiles/FRDtools.html

To get a handle on the the stuff, you can trace the FR and impedance graphs (using SPL trace) for your drivers, and plug that into the software above. Yes, there are some steps in the middle I didn't mention, but there is just no substitute for just getting your hands dirty and trying things out. (there's even a button for "load textbook filter" if you want that to get you started!)