Critique my proposed Zaph ZA5 based build

[PhyrraM]

EDIT: Build finally started, jump down \/

It's been a month since my last "what to do" post. I figure it's likely time for another. :P This time I've got another month of reading under my belt.

I've come up with a plan, but I'd like a little reassurance that I'm not making any obvious or large mistakes.

They say a picture is worth a thousands words, right?



Hopefully most everything in the above pic is self-explainitory. I plan on using the in-wall versions of the ZA5 family, the ZA5.2iw for the centers and the ZA5.3iw for the left and right. I plan on using full enclosures, not using infinite baffles and the wall cavity itself. I am planning on sealed enclosures about 8-10 liters for the ZA5.2 and about 16-20 liters for the ZA5.3s. The wall is 6" thick instead of the normal 4", so these volumes seem very attainable.

I need to decide on a center channel location. A or B? From everything I have read, there is no reason to consider both spots. Is that a fair assumption?

Thanks in advance for any advice.

[numberoneoppa]

Raise the TV up by about 1-2 feet and put the center in A (raised up to new height). The TV seems very low. If you keep your TV at that height, i would say B.

[---k---]

Wow. I didn't know that Zaph had added in-wall version. That is good to know.

I'm not sure option A or B matters much for the center. I think the differences are going to be very slight. 'A' might give a little more bass boundary boost due to the floor. 'B' might have less bass, which could improve speech intelligibility.

[rvsixer]

With the screen height set properly, and trying to keep LCR tweeters at ear level and in as close a horizontal plane as possible, automatically favors the center speaker at the bottom of the screen.

Some vertical display placement guidelines (...from all over the web while I was setting up my HT display):
1) No more than 2/3 of the vertical display height should be above seated eye level
2) Center of display no more than 15 degrees above seated eye level
3) SMPTE limit is top of display no more than 35 degrees above seated eye level

I did not see reference to the size of your display, but based on some of the other dimensions it looks like your TV is anywhere from "just right" to maybe 6" too low.

[PhyrraM]

The screen is a 55" Samsung. Seated ear height for most of the furniture is 36", higher if your tall, lower if your lounging. The TV itself is 32" tall, so that places the ears/eyes about 1/3 up the screen, from the bottom. The TV does seem low when you first walk into the room, but I've never had a complaint once someone sits down and watches it. The height seems very natural with no indications of neck or eye strain.

I did forget to mention in the top post that I do plan on a subwoofer (or two) that I will build after the LCRs, but before the rears. That might make the upper "B" postion more favorable?

[Bear]

The screen is a 55" Samsung. Seated ear height for most of the furniture is 36", higher if your tall, lower if your lounging. The TV itself is 32" tall, so that places the ears/eyes about 1/3 up the screen, from the bottom. The TV does seem low when you first walk into the room, but I've never had a complaint once someone sits down and watches it. The height seems very natural with no indications of neck or eye strain.

This is the correct placement. Most people have their screens too high to WAY too high.

I did forget to mention in the top post that I do plan on a subwoofer (or two) that I will build after the LCRs, but before the rears. That might make the upper "B" postion more favorable?

Neither A nor B is ideal. To make them better, I would adjust the height of the Left and Right speakers to be closer to the design axis of the center channel. If you are contemplating going to a front projection set-up at some point, then go with the lower mounting position. If you custom build your subwoofer, you can get a pretty decently-sized one without masking position "A". For room mode control, two or more subwoofers provide better performance than a single one, so you may want to plan on multiple subs, rather than a single one.

Of course, if you are cutting walls, there is always the "infinite baffle" option for the fully-built in approach.

[numberoneoppa]

I could see the 1/3 rule working for larger projector screens, but for a 55" panel that's a good distance away from the viewer, I can't see how a bit higher could hurt; It would certainly look nicer (my opinion).

[PhyrraM]

OK, so how about version 2.0? Moving the speakers down a bit makes sense.



If I build in a small amount of upward angle into the center channel, what would be the outcome? I assume that if I attempted something like that it's important to keep the woofer and tweeter in the same plane to each other?

[rvsixer]

That moves the LR tweeters down too low (where loss of high frequencies matters). Plan A looked great, tweeters and 1/3 display at ~seated ear height, center located either on top or bottom (which while not optimal, for all practical purposes acceptable since the center focuses on vocals).

Here's some links to HT and display setup:
http://carltonbale.com/home-theater/...ter-calculator (calculates proper seating distance and screen height based on display size/format)

http://thx.com/home/setup/display.html

[Bear]

That moves the LR tweeters down too low (where loss of high frequencies matters). Plan A looked great, tweeters and 1/3 display at ~seated ear height, center located either on top or bottom (which while not optimal, for all practical purposes acceptable since the center focuses on vocals).

Here's some links to HT and display setup:
http://carltonbale.com/home-theater/...ter-calculator (calculates proper seating distance and screen height based on display size/format)
http://thx.com/home/setup/display.html

Eyeballing, the tweeters look to be about 30" from the floor in v2. The difference in angle will be relatively inconsequential to most listeners who are seated (less optimal for people standing) and should improve auditory panning/integration across the front. As I said above, though, none of it is optimal; you merely have to pick which tradeoffs you want to make.

That being said the 5.3c may be a slightly better option, though I don't know whether Zaph has published an in-wall XO schematic.

[PhyrraM]

After taking eveything mentioned into consideration I was this >< close to ordering the drivers and crossover parts. Then I was completely overwhelmed by the crossover component choices. Many different "lines" to choose from.

I assume that the more expensive ones are supposedly higher quality? I also notice that some versions have the values I need, while other series are only close to the specced value. I tried to search up a bit, but my search skills fail me this time.

I also noticed that some of the resistance values stated as being part of the inductor. Will all inductors of a given value have the same resistance? If not, how do you locate/attain BOTH values in one inductor?

Is there a write-up or comparision of all the capaciter, resistor, inductor variations? Is there anything wrong with going for the "lower end" stuff?

Second......
From further reading it seems like a MTM presents best and most evenly when placed vertically, NOT horizontally like most center channels. Is this a fair assumption? Specifically for the ZA5.3?

That leads me to the next question....I assume that if I attempted a verticle MTM center channel (instead of the planned TM), placing the tweeeter between the woofers would pull the soundstage too far from the screen (either high or low)? And the response would change (drastically?) if I tried a TMM on the same crossover, correct?


Sorry for all the newb questions, but it appears the DIY speaker learning curve is a fairly steep one. ;x(

[savage25xtreme]

Unless you are using very high end electronics you wont hear a difference in the crossover upgrades, IMHO. inductors can have the same value and have very different DCR depending on how the inductor is made, i.e. aircore vs iron core vs foil ect.

Yes the MTM need to be designed to be horizontal or vertical. there are a few designs that work well both ways, but the Zaph kits don't, he has a specific design for a horizontal center.

Yes you have to follow his designs and driver layout, they are built into the crossover.

just build the Zaph Center if you want it to be a MTM

[Bear]

I assume that the more expensive ones are supposedly higher quality? I also notice that some versions have the values I need, while other series are only close to the specced value. I tried to search up a bit, but my search skills fail me this time.

This gets into a bit of a religious debate. There are aspects that can be measured and then there are the subjective issues. Among the things that can be measured for capacitors are the tolerance to specification (e.g., +/- 2%) and the ESR (equivalent series resistance). More expensive capacitors should have a tighter tolerance to spec and a lower ESR. Other things that are less measurable on the surface are susceptibility to induced microphonics (which is a mechanical issue), but you can minimize/eliminate this last issue by having the crossovers be physically separated from the air space in which the drivers operate. Zaph tends to use Bennic and Solen capacitors, so you should be fine going with those.

For inductors, substitute DCR for ESR, and, in general, the lower the better. You also want to use air core inductors unless otherwise stated.

I also noticed that some of the resistance values stated as being part of the inductor. Will all inductors of a given value have the same resistance? If not, how do you locate/attain BOTH values in one inductor?

This is where a little shopping comes into play. Going with a lower DCR is usually not only acceptable, but it can be desirable, if a bit more expensive.

Is there a write-up or comparision of all the capaciter, resistor, inductor variations? Is there anything wrong with going for the "lower end" stuff?

It would be expensive to do and open to significant criticism. No high-end cap manufacturer would have enough of an interest in seeing this done to support it financially, though I would have the utmost respect for one that did, and you would basically put a big target on your back for one side of the divide or the other (or both!) to attack your methods and results. Seems like a lot of trouble, hassle and expense to get into a no-win situation.

[evilskillit]

One would assume that DCR is bad and that lower is good. However steel laminate core inductors have the lowest DCR by far and are not recommended unless you can't avoid them in most cases.

Also in a lot of designs the DCR of the inductor is specified, and has an effect on the frequency response. Going lower than the design calls for may not be a good thing. In the project I'm building the DCR of the inductor is subtracted from the following series resistor, so it doesn't really pay to get a super low DCR inductor in that case because you just have to get a higher resistance resistor to balance it out.

I would say if a design specifies a specific type of inductor, awg, or dcr use that. At that point if you want to get one that meets those specs but is more expensive than another one that also meets those specs then that is your choice.

[PhyrraM]

You gotta stop asking questions and dive in sooner or later, right? The UPS guy was here today.





I also have the circle jig combo, terminals, grillcloth and a few other things coming from PE. I have not ordered anything for the crossovers yet. I'm still slightly confused on what exactly to order, but figuring it out is greatly increasing my knowledge.

I do have a question....If I was to build the boxes deeper, and stick the baffles out about an inch from the wall (to give the drivers a tad more depth for back waves), how would it change the sound? From what I have read so far, my guess is to not worry about it for an inch. Fair assumption?

I plan on keeping the boxes themselves fairly simple (ugly), but making an oversize rectangular frame (same height as the TV?) from 1" quarter-round with black grill cloth stretched over it. I would hang this from the wall over each enclosure, kinda like hanging a picture frame. Do you see the ~1" frame or the grillcloth noticeably deteriorating the sound?

I hope to start the enclosures this weekend, but PE has my circle jigs about a week out (so they say).

[ThomasW]

Grill cloth itself absorbs some of the high frequencies, usually that's not a problem.

1" thick recess or grill frame will cause diffraction effects and that will screw up the imaging to a degree..

[numberoneoppa]

Those Zaph drivers look so delicious. Can't wait to see pics of more progress.

[PhyrraM]

Thanks for the tips.

I will plan on some type of "floating" frames using stand-offs from the wall. I will also keep the perimeter of the covers/grill as far as possible from the drivers. I'm thinking that 6+ inches should be attainable.

I plan to take a ton of pictures. The hard part is trimming out the fluff pics to keep posts to a reasonable length. :lol:

[PhyrraM]

I ordered the crossover parts. With luck I didn't make any mistakes.

I used Zaphs's drawings here:



and



My only "scary" desicion was one inductor the drawings called for 1.0mH and 4.0 ohms of resistance. I used a 1.0mH inductor with .5 ohms of stated resistance and plan to bring the total resistance to required 4.0 ohms using a 3.5 ohm resistor in series. Is that the correct way to procede?

For anybody interested the parts list for 2 MTMs and 3 TMs:

2 x 1.5 ohm, 15 watt Wirewound Resistor (15R1.5) = $0.90
2 x Sidewinder 0.7 mH Air Core Inductor 16 AWG (SW.7) = $20.50
7 x Bennic Poly 16 mfd (BP16) = $44.10
2 x Madisound 0.15 mH 19 AWG Air Core Inductor (.15MHL) = $7.00
2 x Bennic Poly 0.47 mfd (BP.47) = $1.30
2 x Madisound 1.0 mH 19 AWG Air Core Inductor (1.0MHL) = $11.00
2 x 3.5 ohm, 15 watt Wirewound Resistor (15R3.5) = $0.90
3 x Bennic Poly 8.2 mfd (BP8.2) = $12.15
3 x Madisound 0.4 mH 19 AWG Air Core Inductor (.4MHL) = $12.00
6 x 4 ohm, 15 watt Wirewound Resistor (15R4) = $2.70
3 x Madisound 1.5 mH 19 AWG Air Core Inductor (1.5MHL) = $18.60
3 x Solen 2.2 mfd Fast Cap 400V (CP2.2) = $7.50
2 x Solen 30 mfd Fast Cap 400V (CP30) = $22.50

[dmalphur]

I think you are thinking the right thing, but in series not parallel. It is odd to not have the characteristic resistance of the inductor in the drawing. I wonder if this is a typo?

[PhyrraM]

Ah, yes. Series...Thank you. Post above corrected for clarity.

[BOBinGA]

John normally has an asterisk on the R in his notch filters which says to reduce R by the resistance of the inductor - exactly as you did. So I think you are OK. In any case, without calculating it, I'm guessing this notch filter is to control the peak around 4k that he discusses in the regular 5.3, so even if you really do need 4 ohms, your 3.5 ohm resistor would only increase the dip in the response maybe a db at 4k. If you find that you need a little more "sparkle", its easy enough to change it to 4 ohms.

-Bob

[PhyrraM]

I found some time this weekend to begin my first speaker project. Actually it's my first woodworking project period. Too bad speakers don't have steel spaceframes or a fiberglass body, I'd feel more comfortable with those.

I started with one of the MTMs. I bought a router and the Jasper jigs, then I read every build thread I could stand. Here are a few pics. The brass screws will be replaced, they are just what I had on-hand.













I designed them to be flexable in thier mounting. The front baffle is oversized by 2" in all directions. The baffle will be bolted to the wall and the enclosure itself will go through the drywall cutout into the wall cavity. I still need to do bracing, and am open to suggestions. :T







And finally, each enclosure can be mounted with the drivers up or the drivers down. I did this because I still haven't decided if the center channel is going to be over or under the screen.





As usual, comments and corrections accepted. And thanks for all your help so far.

[PhyrraM]

I've made a little more progress on the MTMs.

Still waiting on the rest of the crossover components, so I only have the tweeter crossovers started.

[gvimhoof]

Looks like it will be a very nice set up you're going to have. Did you decide on the higher or lower install points. I like the higher, but that's just me.

[PhyrraM]

Looks like it will be a very nice set up you're going to have. Did you decide on the higher or lower install points. I like the higher, but that's just me.

No, I haven't decided. It's possible that the S.O. will override my input anyways. The L/Rs are symetrical so, if need be, they can be inverted - even after install.

The crossovers are finished.



Not sure I can finish the enclosures before a camping trip with the Cub Scouts this weekend.

[lennon_68]

Any progress on this? I'm considering using the ZA5.3iw for a friend's HT build and would love to hear your impressions of them

[PhyrraM]

Any progress on this? I'm considering using the ZA5.3iw for a friend's HT build and would love to hear your impressions of them

They are not completely finished, but they ARE in "audition mode".













Even with only the two channels the sound is very good. Everything is clear and distinctive, and even with normal TV shows (Fios HD) everything is far more enjoyable and immersive. Blu-Rays could really use the full surround sound, but Sherlock Holmes was pretty cool. They don't go super low, but I really didn't feel a overwhelming need a subwoofer for everything. I can certainly enjoy these for a while without a sub. Before, when using the TV speakers, I had to set the TV box to "heavy" compression to make some of the softer dialog hearable without setting the volume so terribly loud on the "explosive" parts. Now it's set to "none" and everything just seems to flow--nothing seems too soft or loud. Except for commercials, that is.

The acoustic filling is wrong (read a few posts on fiberglass, and later a few more to the contrary) and there is no internal bracing yet. Not sure if I will need bracing anymore. I was also planning on doing the center channel before the subwoofer, but upon hearing the "almost" finished product I will likely do the sub first. Imaging is really good and the "phantom" center channel is placing dialog smack in the middle of the screen.

I'm sure there are a few (or many) frequency response problems with them regarding the use of in-wall crossovers, but having them temporarily "wall mounted", but my ears are still just enjoying not having to deal with the TV's crap speakers.

I plan on attempting a piano black type of finish and attempt to match the "theme" of the TV. Also, the regular hex headed bolts will be replaced with either black or stainless steel allen bolts.

[---k---]

Those look great. You did a nice job with them.

The stuffing does look a little heavy. I use fiberglass. It is something you can experiment with.

I agree with building the sub next. You might think that you would be happy without one, but once you have a real one, you'll be glad you did.

[lennon_68]

Thanks for the update. Those are really looking good. It's great to hear that you like them as well

[PhyrraM]

.......... You might think that you would be happy without one, but once you have a real one, you'll be glad you did.

Yeah, I will want a sub long term. I was just trying to add to the mini-review that they are very listenable without a sub. For compairision- most HTIaB systems are not very enjoyable without the sub plugged in.


Thanks for the comments on how they came out. Sometimes you can get into a mode where you see all your mistakes and overlook the overall good job. I think I have almost as much into tools as I do in speakers and crossover components. Mainly to try and "do it right". If you already have a router, clamps, drills, etc., I don't think you can go wrong with anything in the ZA5 series.

[owdi]

Reviving this thread because those resistors look like the 15 watt wirewound versions at madisound.com. Anyone have an idea just how much inductance they have?

[Bill Schneider]

From 2008, here are the findings of dmalphur....

==========

I measured the 2 Ohm 15W resistors I received today from Madisound. Here are the results...

R1
0.10 kHz 1.978 Ohm 0.001 mH +/- 0.001
1.00 kHz 1.979 Ohm 0.0013 mH +/- 0.0001
10.0 kHz 1.980 Ohm 0.00119 mH +/- 0.00001

R2
0.10 kHz 1.972 Ohm 0.001 mH +/- 0.001
1.00 kHz 1.973 Ohm 0.0013 mH +/- 0.0001
10.0 kHz 1.974 Ohm 0.00118 mH +/- 0.00001

That clears things up for me, these measurements make a lot more sense. I used a fixture for the measurements this time rather than clip leads. Measurements were made on a HP4192A impedance analyzer with 16047A test fixture.

I'm not worried about this minuscule inductance affecting the performance.

-David
======

Bill Schneider

[evilskillit]

Btw, those do look nice, definitely sub for next project Also you and I are of the same school of thought, can't have enough screws holding a baffle on.

[PhyrraM]

Late response, but unfortunately I have spent the last few months working 400 miles away from home. So the speakers are just the same as the last report. I really want to finish them and get them permanently flushed into the wall.

I was winging it on the baffle mounting, but it came out strong and stiff. So I am pleased.

They still sound awesome and those Zaph drivers are dealing with everything that Onyko can throw at it. Being new to the DIY scene, I'm amazed at the excursion those little drivers can handle. I tempted to do Zaph's in-car version, just to see how it compares to the Alpines currently in my Subaru.

[tominizer]

hope you don't mind me pulling this back from the dead, but how did this in-wall project turn out ???? I'm considering the same project.

[Hank]

Well...personally, I don't think you used enough BLUE painter's tape :W

[PhyrraM]

Speaker-wise the project turned out great. Everything worked and sounds great. I was originally worried about possible rattling against the drywall, but it turned out to be a non-issue and the speakers were mounted in the wall with regular drywall toggles and long black allen head bolts through the face. of the baffle.

Appearance wise, my first attempt at a shiney black finish to match the TV failed - miserably. Runs, scratches, dull finish. I am a mechanic by trade, not a woodworker. I made new baffles, and am currently trying again. I enlisted the aid of a coworker that is a much better carpenter than I.

I have not started a center channel or sub yet, but will soon.

[Outfitter]

I am looking at the ZA5.3iw and am confused by the crossover layout at L6 and R8. I saw in an earlier post that you had the same issue. Does anyone know if this is a typo? Comparing to the standard MTM it looks like R8 (which I am comparing to R4 in the ZA5.3c) may be used across the tweeter?




Any ideas?

[lzrdkng14]

Speaker-wise the project turned out great. Everything worked and sounds great. I was originally worried about possible rattling against the drywall, but it turned out to be a non-issue and the speakers were mounted in the wall with regular drywall toggles and long black allen head bolts through the face. of the baffle.

Appearance wise, my first attempt at a shiney black finish to match the TV failed - miserably. Runs, scratches, dull finish. I am a mechanic by trade, not a woodworker. I made new baffles, and am currently trying again. I enlisted the aid of a coworker that is a much better carpenter than I.

I have not started a center channel or sub yet, but will soon.

Wanted to bring this back again and see if you could post some final pictures of your project? Thanks