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Austin DIY HT Projects - Page 5

post #121 of 1248
Thread Starter 
Colin wrote:
Quote:
My movie screen is FINALLY finished and up on the wall!!!

CONGRATS!!! (and the seating looks very comfortable, can't wait for the demo!)
post #122 of 1248
My next DIY project has begun. I'm rolling my own MTM tower speakers. After changing my mind on drivers at least ten thousand times, I ordered some PE buyout Vifa drivers (PSB OEM I think). I placed the order shortly after deciding against MTMs as a first project. Heh.

Haven't picked the tweeter yet. I'll probably use the Vifa PL tweeter.

Anyway, I'll keep y'all posted.
post #123 of 1248
The big brown toy truck just dropped 'em off.

Here's a picture of all ten: Vifa TC18WG-35-09 woofers

I had so many choices... I was all set on doing a 1-woofer 2-way with the Peerless HDS that Mark Hayenga uses. I really liked the sound when I heard his, and I also liked the cut-side frame. I wanted to spend less money and have more efficiency, though. The pickins are slim when it comes to cut-side woofers, but I think these should work out well and be a great value.

They are apparently the woofers used in the PSB Stratus Bronze tower speakers. I'll be doing a 2-way MTM, though, rather than 2.5-way.
post #124 of 1248
Jeff, I assume you know how much effort is required to design a speaker system, the heart of which is the crossover. Are you getting some expert help? No offense intended, just want to make sure you have a good experience with the results. Are you going to build five towers?
post #125 of 1248
I haven't worked with the -35 version of those drivers, but I have experimented with the -49 version. Assuming the 35's use the same motor, then you'll probably be using a sealed box alignment. Watch the power handling in the low end, they tend exceed xmax fairly quickly. As long as you're crossing over to a sub with at least a 2nd order highpass on the sats around 80Hz you'll be able to crank it as loud as you want. The TC woofers are a high quality woofer for the price, I'm sure you'll like the smooth sound they can produce.
post #126 of 1248
What is meant by a "2.5-way" design? Would that be two identical woofers covering different frequency ranges?
post #127 of 1248
Hank: I'm definitely aware of the steep learning curve and amount of effort required. Since the sub project, I've learned a lot already by reading huge amounts of material online. I certainly have much more to learn, and that's really why I want to design my own rather than build a kit I want to do the hard design work myself. More than that, I want to KNOW how to do it, and be able to do it again. The engineering process behind it interests me as much as actually ending up with some great speakers.

As for expert help, I have you guys. Mark has offered to help me get measurements once I'm ready. After that, I'll take the response files, plug them into LspCAD, and start modeling crossovers. Once I actually put a crossover together, I'll bring 'em to a meet and have you guys critique them. I won't mind being sent back to the drawing board.

I was planning to build 5 towers, but I think I'm actually going to build 3 MTMs for the front (with the center tower standing up like the left and right) and some 2-ways for the surrounds. I got to thinking, and I realized that MTM surrounds elevated ~3 feet above the audience might be a bad idea due to the narrow vertical dispersion pattern. I'll probably shoot for 2-ways with a slightly down-pointing phase lobe. This will leave me with enough leftover woofers to go 7.1 someday. Or 6.1 with a floorstanding MTM rear center.
post #128 of 1248
Jonathan: these have an EBP of 61.5, so I guess they're in the "can go either way" category, leaning towards sealed. I haven't decided on sealed vs. vented yet. I don't have LspCAD yet, and I've just been messing around with WinISD to look at response curves. LspCAD provides much more useful info with the excursion graph.

The EBP and the PE site ("a great sealed-box woofer") indicate good sealed performance, and the woofer's intended application (PSB Stratus Bronze) indicates good vented performance. If I go vented, I'll make sure it's a very well damped alignment. I might try both... I'm in no rush to have a finished set of speakers.

Mark says you've worked with the D27 tweeter and you didn't think it was that great. I'm considering going with the PL27TG-35 tweeter; I've read reports that it is smoother than the D27. Have you ever used/heard it?

EDIT: Yes, they will be crossed over at 80Hz to an EBS Shiva with my Onkyo SR500, which SURELY uses a second order or higher slope. Right?
post #129 of 1248
Colin: A 2.5 way is a normal 2-way with the addition of a second woofer to handle the baffle-step compensation. In other words, one woofer's response runs all the way up to cross over with the tweeter, and the other woofer only goes up to around 500Hz (or whatever is required due to the woofers response and baffle width).

Baffle-step compensation is required since lower frequency wavelengths "wrap around" the baffle. In other words, the woofers energy is spent radiating into 360 degrees rather than 180, speaking 2-dimensionally.

I'm not quite sure how this would apply to dipoles like your Maggies. You'd get more bass response pushing a monopole speaker against a wall since the wall would act kinda like a baffle, but pushing your maggies against the wall would cause the backwave to cancel out the bass.
post #130 of 1248
Yeah, I wasn't overly impressed with the D27's, they always sounded a little harsh and sibilant no matter what I tried. The sibilance could have been a diffraction issue, but I think the harshness was inherent to the tweeter. I preferred the sound of the D25AG. Contrary to stereotype I actually find the D25's aluminum dome to sound smoother than the soft dome of the D27. I haven't tried the PL27. If you're interested in giving the D27's a shot I have some I'd let go cheap, maybe you'll have better luck with them than I did.

In general I prefer Morel tweeters over Vifas. You might want to give the MDT-20 a shot. I don't have any personal experience with it, but based on past experience with Morel I'll wager it will sound better than an equivalently priced Vifa. Pure speculation however.
post #131 of 1248
Pssst...Jeff buddy...wanna buy some cone dope?
post #132 of 1248
Hank: I would, but I spent all my money on LsdCAD.
post #133 of 1248
Jeff,

Ok, so what are you going to do on the video side of things? Having a 3rd vertical tower for a center channel is ideal, but it tends to block visibility of the TV.

I still need to come over sometime and hear the sub. I'll bet I can figure out a way to do front projection too.... After all, if its not FPTV, its just a picture inside a box! :-)

I just added a Samsung T160 sat/OTA HDTV receiver. Should be here today and will have it setup on Saturday. Can't wait to watch some HiDef NHL games on HDnet.

I'm also adding a 7.1 receiver and another set of speakers soon. Probably a Denon 3803. Wish I could do full size surrounds but you've seen my setup - wouldn't really work. And the HT room is getting painted a darker shade for less light reflection. And the screen is getting hooked to X10. And, and, and..... My annual winter "upgrade the theater" kick has begun in earnest.

-Dave
post #134 of 1248
Jonathan: I was seriously considering the MDT-20. Nobody responded to my PE Tech Talk PL27 VS MDT20 post, though, and I ended up putting "a pair of PL27's" on my Christmas list. I imagine I'll get a pair.

I really hope the PL27 doesn't have much more than a "27" in common with the D27 after hearing what you have to say. I'll ditch them if they're sibilant. I certainly don't consider my audio connoisseurship even close to audiophile level or anything, but my ear is sensitive enough to sibilance.

I was considering the D25, too, but it (or one quite similar) is used in the PSB Stratus Bronze (like my woofers). Perhaps it's a silly/immature reason to avoid a tweeter, but I don't want to make a speaker that could be viewed as a "PSB wannabe".
post #135 of 1248
Hey Dave. The video side of things will most definitely be "front projection". The center tower will probably get in the way of 4:3 material if I go with a 4:3 projector, but I'll be using an HTPC and can presumably scale the image down for that if necessary. We won't watch a lot of TV in the HT room, so I don't see this being a problem. If it DOES become an issue, I can build a shorter enclosure that is deeper to achieve the same volume with the same baffle width.

What projector? Who knows. While I'd ultimately like a DLP projector (particularly the InFocus X1), I might try to start out with something like Paul Laiming's eBay steal of a CRT projector and move up from there as budget allows.

None of this is going to happen anytime soon, as it will require us to move to a house with a suitable HT room. I'll have lots of time to tweak those crossovers.

Yeah, we could cram front projection in the current living room, but it would either require a portable screen to be set up every time we watched a movie, or reshuffling of the furniture to the point where it's no longer suitable for use as a living room / walkway.

BTW, you're welcome to come hear the sub anytime. But I'd REALLY love to bring it over to your place. My living room air volume is just too huge and the sub's placement is just too bad for you to get a good feel for it. It sounds excellent when you take those things into consideration, but it could be so much better. I can borrow my friend's Explorer.
post #136 of 1248
Jeff,

The Infocus X1 seems to be getting a tremendous amount of positive comments. I think, for a $1500 unit, it will open up FPTV to a new market. I think it would be fine for DVDs as long as you sit 1.5x back.

As for CRT...well, as a former "CRT snob" myself I can say that CRTs have the best picture -- *when* they are perfectly converged and in total darkness. However, I've looked at many different CRTs, some of them professionally converged, and none of them were perfect. IMO, with the latest batch of DLPs, I think CRTs are no longer worth the hassle.

You never saw the @#$@ crap I had to go through to get my 170lb Zenith (identical to a Runco 990 I think) mounted on the ceiling (including reinforcing the joists in the attic). Or the entire weekends I spent tweaking the convergence. Or the lovely 2.35:1 burn-in silhouette I got on 4:3. Sorry, but I've never once regretted selling my "reference quality CRT" for a digital projector.

However, there are some good deals out there. Curt Palme on AVS has a bunch of used CRTs. Also, a buddy of mine in Ohio has a Zenith Pro900X he'd sell cheap.

As for the Subwoofer, PLEASE feel free to bring it over. I plan on building one after I finish a few other things first. I'll provide dinner and all the movies you can watch. I also have HDTV now, too. I might even let you drive the E30 M3 down Lohmans Ford Rd ;-)

-Dave
post #137 of 1248
Hmm, I think CRT vs digital has become the videophile version of LP vs CD in the audiophile world. I won't argue, I'll just say I'm still a CRT snob. The key to good convergence is to get the mechanical setup right first then converging is just a bunch of tweaks. Of course I love tweaking so CRT's are right up my alley.

HOWEVER, Dell just released a new DLP with 1300 lumens and an 1800:1 contrast ratio. Price? $2199! Those things are getting affordable! I don't know any details on the color wheel yet, but I'm trying to get some info.
post #138 of 1248
If it's an HP xb31 clone (which it looks like) it's probably 2x RGBW.
post #139 of 1248
You're correct about the color wheel, 2x RGBW with independant RGB color adjustment and 0-100% use of the W segment via the OSD. Don't know about the clone part. Sounds like a pretty good deal to me, in the same league as the Sharp MX20 for a bit less money. The lower speed wheel might cause more rainbows though.
post #140 of 1248
Thread Starter 
Don't you love the way projector technology has skyrocketed over the last few years while prices have plummeted. After all, it was less than two years ago that a DLP projector with 800 lumens and a 1000:1 contrast ratio was state of the art "High End" and sold for nearly $15,000.

At this rate, I suspect by 2005 we will see native WXGA (1280x720), 2000 Lumen DLP projectors with contrast ratios of greater than 4000:1 (well beyond even CRT capabilities) selling for less than $5,000, and for the High-End group they can expect to have true native 1080p HD resolution projectors (WQUXGA 1910x1080) - most likely LCOS based, and not DLP, but hopefully with much improved ergonomics and greater contrast ratios.

Its a great time to be interested in HT, certainly a far cry from ten years ago when you would have had to spend at least $25,000 on decent CRT, then of course you'd want to spend at least another $15,000 on a reasonably good line doubler, and another few thousand on a high gain screen (to compensate for the low, low, low lumen output from the CRT. And after the hours of reading the manuals, installation, and calibration, what did you have for all that effort and $50,000 or so? A 84" image in a pitch black room, displaying non anamorphic $75 Laser Discs... oh my how the times have changed!

I suppose the hard part for those that are on the fence is when is the right time to jump in. Personally I'd say NOW, as then you will at least get to enjoy the world of true widescreen, but I still wouldn't recommend anyone buying any of these so called state of the art projectors that sell for over $10,000. They depreciate faster than a brand new Cadillac, and even faster than state of the art computers. The nice thing about the sub $5,000 market is that not only is the depreciation significantly less, but it is much easier to sell your unit later down the road as there are always bargain hunters looking for a cheap entry into the world of HT. Not only that, but there frankly is not that HUGE a difference in performance between the $5,000 units and the $10,000-15,000 units. Sure, they will probably have slightly better PQ, and some will offer extra features, perhaps better support, but 2-3 times as much? Not even close. In my opinion they might have about a 10-20% performance/feature improvement over those in the sub $5,000 range. Now, if you have the extra cash to spend, sure, you will get something for it, but for me, I was, and continue to be very happy with my $5,000 unit which I have now had since May.
post #141 of 1248
Thread Starter 
Regarding color wheels, you may also want to make sure that you get a projector that allows for the white segment to be deactivated for HT use. While the white segment is great for data and game projection, it washes out video. I've read some video reviews of projectors with white segments that can not be deactivated saying how great the picture was because it looked "snappy" and bright... well, that may be true, but at the cost of removing a lot of shadow detail from the image, which I personally would not want to lose.

The nice thing though is many new DLP projectors give the user the option of having it on or not thus allowing for personal taste to determine the PQ. After all, video is perhaps even more subjective than audio, thus what may look fantastic to one person, could look mediocre to another.
post #142 of 1248
Nils,

Yes, digital projection has come a long way. For DVDs and normal TV I think the Infocus X1 would be ideal. Its got great contrast, a great processor (Faroudja DCDi), and is $1500. Granted, its not ideal for HDTV but I'd bet it'll rock for DVDs.

My NEC LT150 (which was the king of the hill when I bought it 2yrs ago) still puts out a great picture and was $2300.

The new NEC HT1000 is getting an amazing response. 3000:1 contrast, superb color and scaling, tons of tweakable settings, masking (the one thing I miss about my CRT), etc. Its ~$4K now but a price drop is expected soon. I think this projector will be the one to have for a while. NEC's business projectors have long been a favorite of the HT crowd, and NEC is now designing them specifically for HT.

As for the Dell, I can probably get you a discount of somewhere between 10-25%. My wife works there and one of my best friends is a Business Sales Rep for Dell. He always swings good deals on my LT150 bulbs.

The Sharp PGM20X has stunning specs for the money. I haven't seen one in person, though. The NEC LT240 is also a good one to check out.

The Sharp 9000 is available for <$5K if you mail order it.


I'll hold on to my NEC until I see one thats 1280x720, 3000:1 contrast, 1500+ lumens, DVI input, good processing & tweakability, and <$4K. I have a feeling someone will meet these conditions within 6-12 months, probably NEC.

My CRT envy waned the day I carried my 3.3lb projector over to a buddy's house for a halloween party. It was a hit.

Anyways, I just designed a system for a guy here at work. Infocus X1 ($1500), Dalite model B pull down 100" ($200), HK 125 receiver ($325), Panasonic RP62 DVD ($190), and Atlantic T70 5.1 system ($700). For less than $3K he'll have a system that would have been unthinkable for $25K a couple of years ago.

I *love* how affordable high-end theater is becoming. Finally, I can afford some of the things I always thought were unnattainable. It is truly a great time.

-Dave
post #143 of 1248
Add me to the list of digital projector fanatics. I have seen really good CRT pictures, but CRTs are just not portable and require a lot of work to set up. Even my "antique" Sony 10HT is a 20lb. box that can easily be moved.

When a true 1920x1080 DLP comes out at a street price of <$3,500, it will probably be time for me to upgrade, but I think it'll be a few years before we get to that point. Until then, the 1366x768 resolution of the Sony will suffice...

I am glad to see projector prices coming down (even though it means my Sony has little resale value anymore). RPTVs are such big, bulky, unwieldy boxes, and they should go the way of the dinosaurs. With high lumens and contrast becoming more and more affordable with FPTV, it will soon be possible to watch FPTV even in rooms without light control. When that day comes, it will be time to turn all those RPTV cabinets into fire wood! I think lots of people like plasma displays because of the sleek, thin, "picture frame" appearance. You can get the same effect with FPTV and a movie screen on the wall ... and not to mention LOTS better picture quality for the money.

Good sound systems are more affordable than before. Starter "Home Theater in a Box" kits are a few hundred bucks. Once you outgrow that and want high-definition audio, a 6.1-channel all-Magnepan speaker system can be had for a few grand (including a subwoofer). I don't know why people spend over $5,000/pair on speakers, as the returns diminish at least as rapidly as they do for projectors.
post #144 of 1248
I'm obviously outnumbered here, but I still prefer CRT because of the image quality. I'm willing to put up with the difficult mounting, long set up procedures, and tweaking needed to use a CRT to its fullest just to get that film-like experience in my home. I'm not religious about it though, I'd certainly put a little DLP in a second setup and be quite happy. I'm just after "reference quality" in the Miniplex. I agree with Nils on the rate of advancement of digitals. I'll probably stick with CRT for another 3 years or so, at which time the digitals will be so good there won't be any reason to stick with CRT.

Of course I'm also the guy who would happily spend well over $5k for a pair of speakers if I had the money. Yes, the returns diminish (that's why it's called the Law Of Diminishing Returns) but if the only way to get to your desired level of fidelity is to spend that kind of money, then that's what you do. It's not for everyone.

Unless we start talking about building a projector I think we're veering a little off topic!
post #145 of 1248
Jonathan -

To veer slightly back toward the topic here ... since you're shooting for reference quality in the MiniPlex, did you ever build those speakers with 6' ribbons that you were planning earlier???
post #146 of 1248
Those are still in the works, the cost to build those things is enormous. They will get made, we just have higher priorities at the moment.
post #147 of 1248
Jonathan -

I thought you'd already bought & paid for the most expen$ive component in those speakers, the ribbon drivers themselves. Guess I'll just cool my jets & listen to my Maggies while I wait for the Mirus Audio Maggie Killer (tm) to get built...
post #148 of 1248
Well when you're buying extremely high-end woofers in quanities of 20+ for a single pair of speakers, the ribbons are actually the cheap part!
post #149 of 1248
Jonathan - I guess you never told me anything about the design. I thought it was going to be a single woofer + ribbon tweeter combination, like some of the dynamic/ribbon or dynamic/planar hybrids that have been on the market before...

Ten woofers plus one ribbon in each speaker? Those might make the GR Research prototypes that Hank built seem compact by comparison...
post #150 of 1248
Not to mention the DSP development that has to go into them.....


:b
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