Planning a Zaph Build - help please

[swinginguitar]

I'm prepping to build a small set of monitor type speakers for desktop use (enjoyable listening but occasional music production/mixing for fun).

At the moment I'm leaning to the Zaph ZA5.2, though I had considered the SR71 as well.

Some questions about the 5.2:

1) Zaph's recommendation for nearfield use is to use th BSC circuit, as well as the smaller .25cf cabinet size. Also mentioned is to raise the tuning of the cabinet to 55-65hz. I'm no designer - does this mean to make the port tube shorter in length?

2) Aesthetically I would prefer a vent to a port (and i think it may fit the smaller enclosure better without crowding the woofer) - can someone assist me in calculating the dimensions of a vent? I read that it's the same area as the circle of the port, and the same length/depth as the port....is this true?

3) According to the site, the higher tuning and smaller cab leads to "power handling issues". What does this mean and shoud I be conerned?

4) what pwr amp specs would you pair with this? for the interim i'm using a prosumer pa/monitor amp, but will upgrade later...have my eye on the emotiva stuff at the moment.

5) what sub would match with this? (commercial or kit either way) i have a Klipsch sub from a multimedia setup, but not sure if i could hack in and bypass/tweak the crossovers etc...and the inputs are on a ps2 type connector that would have to be dealt with assuming the circuit is mod-able.

6) do i want my sub crossover point at the resonant peak of the monitor cabs, or...?

[JonMarsh]

I'm prepping to build a small set of monitor type speakers for desktop use (enjoyable listening but occasional music production/mixing for fun).

At the moment I'm leaning to the Zaph ZA5.2, though I had considered the SR71 as well.

Some questions about the 5.2:

1) Zaph's recommendation for nearfield use is to use th BSC circuit, as well as the smaller .25cf cabinet size. Also mentioned is to raise the tuning of the cabinet to 55-65hz. I'm no designer - does this mean to make the port tube shorter in length?

2) Aesthetically I would prefer a vent to a port (and i think it may fit the smaller enclosure better without crowding the woofer) - can someone assist me in calculating the dimensions of a vent? I read that it's the same area as the circle of the port, and the same length/depth as the port....is this true?

3) According to the site, the higher tuning and smaller cab leads to "power handling issues". What does this mean and shoud I be conerned?

4) what pwr amp specs would you pair with this? for the interim i'm using a prosumer pa/monitor amp, but will upgrade later...have my eye on the emotiva stuff at the moment.

5) what sub would match with this? (commercial or kit either way) i have a Klipsch sub from a multimedia setup, but not sure if i could hack in and bypass/tweak the crossovers etc...and the inputs are on a ps2 type connector that would have to be dealt with assuming the circuit is mod-able.

6) do i want my sub crossover point at the resonant peak of the monitor cabs, or...?

1) Yes, that means to raise the tuning via a shorter port - suggest WINISD or Unibox for checking that, though a pragmatic way is just to get one of the variable slider ports from PE and adjust to get the right characteristics (can be seen in impedance curve minima for port tuning)

2) yes, that's basically correct- and there you see the rub- as high aspect ratio vents don't work very well (too much flow resistance). In practice, you'll probably need to increase the area and length, which may be a problem in a small enclosure.

3) This occurs because the woofer will unload at lower frequencies, due to the different port tuning. By moving the tuning up, you reduce the power handling at low frequencies below the tuning frequencies. So, stay away from heavy hip Hop, for example! :W or keep the standard tuning.

4) For a desktop nearfield use, 25 watts per channel or more should be fine- 50-75 is probably all you can use with this system and the modified tuning, and even then, I'd exercise a little restraint.

5) Now THAT is a very open ended question- it all depends on what you want, and does your source gear have the Xovers built in? There are lots of sub kits and pre-built subs at many price ranges, but with the cabinets and drivers available at PE and Madisound, I tend to prefer rolling my own. A single 8 or 10 in a 1 cu ft might be a reasonable point for you. A lot depends on budget, of course. With regards to your Klipsch, if you can find schematic info on line, re-using that for now might be possible, but I know that can be tricky- I have an old Microsoft/Philips 2.1 system on my Mac Pro that was one of the first USB speakers ever, and it uses the DIN connectors, too, so it's either all or nothing, for the most part...

6) To get a smooth integrated crossover point, you should be planning on both the sub and the "mains" having wide enough response to have an octave of overlap around the crossover point. So, if you're tuning the table tops to 55-60 Hz, I'd be shooting for an 80-90 Hz crossover point, so that the port output is still working in the transition region. After the nominal response is 12 dB down or more, not so important. Remember, a ported system has a fourth order roll off BY ITSELF at the port tuning frequency, so you don't want that combining with the electrical crossover at the nominal crossover point- you'll have both phase and response level issues.

[swinginguitar]

That's good info, Doc Brown!

You hit on another subject I'm wondering about: deisgn considerations for a vent. Are there rules of thumb for width/height?

Many designs have one running the width of the cabinet, but a quick pass at a calculator shows that as it gets wider or taller, it has to be deeper. Are there tradeoffs of making it too narrow/short in order to make the depth practical?

[swinginguitar]

Concerning the sub - ultimately I want a preamp that will tunably crossover the signal between the mains and sub, rather than control it at the sub itself.

I'm thinking an 8" sub would suffice for my smallish room. are the pwr amps sold with/for the kits reasonably good? Given that a basic Dayton kit is around $400 at PE, I'm wondering if it woul dbe worth it vs buying a ready made sub..?

[PMazz]

I had this one bookmarked.

JLAudio port tutorial

[JonMarsh]

Concerning the sub - ultimately I want a preamp that will tunably crossover the signal between the mains and sub, rather than control it at the sub itself.

I'm thinking an 8" sub would suffice for my smallish room. are the pwr amps sold with/for the kits reasonably good? Given that a basic Dayton kit is around $400 at PE, I'm wondering if it woul dbe worth it vs buying a ready made sub..?

That's a real good question, and in the end, it all depends on your expectations and desires. If the hangover and muddle/rumble of a ported/PR sub is OK in your application, then researching built options in your price range is probably reasonable. I'm more into music than HT sound effects, and for me, the tight transient response and low overhang of an IB (infinite baffle) sub is my "reference" standard, and what leads me to usually do sealed subs with LR EQ for a box. (Linkwitz/Riley). That narrows the choice of plate amps to a degree. It's still best to have a subsonic High Pass filter to protect the woofer.

So, build or buy? KEF has a good 10" sealed sub (well, decent may be the better adjective, as we can definitely do better with DIY).

KEF Q400BL: $699




But would it compare with combining a PE Enclosure



With a Hypex digital plate amp with full controls including LF EQ,



With the new PE DVC 10" long throw sub driver (3/4" Xmax, dual spiders, dual VC?



Not at all. But the latter might be total overkill for you. I used this example because it's a situation I'm dealing with for a friend, and her friend who's undecided about their upgrades. You'd be looking at a somewhat smaller solution, but the issues are comparable, just scaled down.

Putting a sub together like this is an afternoon's work, but obviously that's more time that just unpacking a box! On the other hand, a little more money, and a heck of a lot more sub!

Something else to consider- possibly overkill now, but then ready for your next system requirement.

Lastly, take anything I suggest with more than a grain of salt, because as anyone who's spent some time around the board will tell you, my motto tends to be, "If some is good, more is better, and too much is just enough!". :W

[Face]

I'd rather turn down the gain than have to worry about a sub running out of steam. Concerning subs, it's always good to go a little overboard.

[Hdale85]

If you are going to buy one, look at the Emotiva DSP subs, they are quite cheap (600 and under I think?) and they have some pretty decent room correction and what not in them. I think DSP's and room correction are the only reason to buy commercial subs right now. But you are starting to be able to get those things in the DIY crowd as well via things like the Hypex DSP plate amps, but they aren't very cheap currently.

[swinginguitar]

Hdale85: the Emotiva stuff looks good to me - any experience with the preamps/power amps? Their pre looks nice...plenty of inputs/clean construction/crossover outputs....

Back on the subject of Zaph....do you guys think the SR71 kit would be worth the +$200 over the ZA5.2 kit (for nearfield use)?

[oneplustwo]

I've built both. For nearfield in particular, I would say the difference wouldn't be worth the difference. However, I would encourage you to think long term as well. In other words, if you feel there's a good chance these would be more than near field later on, then perhaps the price difference would be less of an issue. And in that case, the difference in "character" between the ZA aluminum driver vs. the SR71 reed cone along with any advantage (real or perceived) in the tweeters becomes more of a factor.

My 2 cents.

[Hdale85]

I've never had any of their pre's but they get good reviews. I love their amps though and I've heard great things about their speakers and what not.

[swinginguitar]

great info!

oneplustwo: my thinking is if i ever got away from nearfield iw ould likely build some large MTMs or floorstanding TMM+, in which case the ZA5's would remain nearfield or be repurposed elswhere...

[swinginguitar]

Also, would you recommend the stock XO, or the reduced BSC circuit for my application (nearfield)?

Can you describe the difference? The graph looks like one way has less high/more mid...?

[Hdale85]

The non BSC version is for placement on or in walls.

[swinginguitar]

any dis/advantages of moving up to the TMM design (ZA5.3tt) for nearfield use?

[JonMarsh]

any dis/advantages of moving up to the TMM design (ZA5.3tt) for nearfield use?

The more drivers and the larger the total source, the more distance you need for complete integration. A particular point is that the .5 driver is primarily in the baffle step compensation range. Takes about a meter from the cabinet for all the balance stuff to start to be sorted out.

[oneplustwo]

Re: Emotiva... I've been really impressed with their XDA-1 DAC which has since been replaced by the XDA-2. I use the balanced outs directly to my XLR terminated headphones and it's better than almost everything I've used except perhaps my dedicated balanced B22.

I also have their XPA-2 amp. It's really good for the money. I haven't been super impressed by it, but no regrets. Especially since I bought it used for a good deal. I prefer my DIY Pass F5 but it doesn't have as much power so when I want to rock out a bit more, the XPA-2 is called up. I have a couple mono Aleph X's in progress though so the XPA may be on the market soon.

Back on topic, ditto what Jon said about TMM. I would stick with the normal x-over two way. This gives you more flexibility for different applications later on as well vs. being forced into an in-wall implementation. No significant advantage for nearfield use. And if it's going to remain nearfield, you certainly won't need the additional power handling.

[Hdale85]

I don't think its exactly fair to compare a pass labs clone to anything from Emotiva except maybe the XPA-1 or XPR series lol.

[swinginguitar]

I know most subs have an adjustable LPF, but is it also advisable to put a HPF on the monitors/mains to limit what low freqs get to them for efficiency?

I'm thinking through my amp/preamp setup for this - is there a good but simple design out there for a preamp/attenuator with LPF and HPF outputs for mains/subs?

[oneplustwo]

I don't think its exactly fair to compare a pass labs clone to anything from Emotiva except maybe the XPA-1 or XPR series lol.

Yes, perhaps. But about the same amount of money into my Pass stuff.

[Hdale85]

And you're comparing DIY to commercial, the money you spent on the DIY build would be many multiples of what it would of cost to produce the Emotiva amp. The real Pass Labs amp would of been many thousands.

[oneplustwo]

@Hdale85: Yes, exactly. My only point is that the comparison is "fair" because the costs involved are similar. But through your lens, it's a bit David vs. Goliath isn't it?

Back on topic for swinginguitar: I'm also looking for a good LPF/HPF for a 2.1 setup. Outlaw has one that is currently in htguide's pawn shop (ICBM) but it's more geared toward SACD use. I've seen a few others from Behringer that could work and am also considering an Emotiva pre (USP or XSP). Or maybe even the DCX2496 since it could be repurposed later on for an active setup. Would love to know how others have done this.

[swinginguitar]

the emotiva crossed my mind for sure.

the Behringer angle got me wondering about other pro audio type xovers, such as DBX, Ashley, et al

(i'm no gear snob, but Behringer stuff is cheap and often not so cheerful...on the inside)

[Hdale85]

The behringer amps have been used a ton for home audio.

[Face]

Pro amps are fine if you don't mind fan noise. If you're willing to try one, I'd look to Crown or QSC, you can always swap in a quieter fan with the Crowns at least...

[oneplustwo]

I was thinking less the amps and more the crossovers. Either the DCX2496 or the CX2310/3400.

[Hdale85]

Those crossovers are actually used a ton in the DIY home audio crowd as well lol.

The Behringer's have a lot of fan swap tutorials as well. I'm looking at an amp right now I think I might go with the Behringer EPX2800, but I've thought about using the iNuke series as well but I don't really want any lights on the front if possible lol.

[swinginguitar]

I was thinking less the amps and more the crossovers. Either the DCX2496 or the CX2310/3400.

ditto - i was referring to xovers, not amps

[swinginguitar]

@JonMarsh:

do u have a link to this sub you referenced (or recommendations for good value sub drivers in the 8-10" range?):

[Face]

@JonMarsh:

do u have a link to this sub you referenced

https://www.parts-express.com/Dayton-Audio-UM10-22-10-Ultimax-DVC-Subwoofer-2-ohms-Per-Co-295-510?quantity=1

[swinginguitar]

Can u guys recommend a good value sub (driver) and associated cabinet design for a small room system that would pair well with the nearfields to be built?

I want to run a pair of subs - i will be crossing over and amplifying externally.

[oneplustwo]

I built a simple 12" Dayton Audio one (see sig). It's zaph's cabinet design and pretty basic. Not sure you need two for small room in nearfield use but "need" is certainly subjective!

[swinginguitar]

LOL..."need" is certainly subjective

was thinking 2 smaller subs as opposed to one larger, but then I don't know much about system design.

Even though people are quick to throw out blanket statements like "lows aren't directional", one of my peeves is hearing the upper end of the lows firing from the side where the sub is....so was wanting to put one either side since i would be crossing over relatively high.

[Face]

2 smaller subs would give flatter response in room.