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NEWB with some questions

4K views 27 replies 2 participants last post by  Bocephus 
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#1 ·
hello all. first things first, im brutal at spelling, so go easy on me. im looking to build a budget 2.1 set up for my house. im realy in to music, so my choices are more geared to that then HT. im looking to build a set of MTMs. ive pic out a set of Dayton DA175-8 7" Aluminum Cone Woofers, a Dayton DC28F-8 1-1/8" Silk Dome Tweeter, and a Dayton XO2W-2.5K 2-Way Crossover 2,500 Hz. the Xover are pretty nice casue u can select eather a 4 or 8 ohm woofer. i plan to use a pair of the 7" drivers in parallel for a 4ohm load. my question is. what would you recomend the volume and tuning be for the pair. Dayton recomends .5 cu per driver and tuned down low to 30Hz. this seams a bit low for a mid bass.

i have a pretty decent car audio back ground and sub woofer enclosure design. i rarely tune a sub this low, and mid bass usaly is on a HPF of 60-70Hz. so this is a whole new ball game for me! once again im looking for input on new volume and tuning for the pair, i can handle the rest from there. thanks
 
#2 ·
So you say you're doing a 2.1 system? By that, can we presume you mean you'll be using these with a subwoofer? If so, there's no reason you couldn't do a sealed box. If I were given those woofers and forced to use two in a 1.0 cubic foot box, yes, I'd probably go vented just to get a little extra power handling. And tuning to 30Hz I'd probably also do, because the high Qts doesn't really make that driver all that suited to vented boxes, especially small ones. If you tune it much higher than that, you get a big hump in the low end response. In fact, I might even tune as low as 25Hz. If you are stuck on using this driver, I would at least double the box size to two cubic feet for the pair. Still tuning to 30Hz, that would give you tremendous bass. But again, if you're using a subwoofer, do you need it? If I had a choice, I wouldn't use them in the first place because of all the nasty cone breakup above 4kHz (those huge jaggy spikes in the frequency response graph). I'd prefer to use the DC160-8 Dayton woofer, which has a much smoother rolloff and takes a considerably smaller box. I'm using it successfully in a design with no low-pass at all on the woofer.
 
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#3 ·
yeah looking at the freq response graph, it does seem to get a bit hairy above 3kHz. ok scratch that then. perhaps i should stated that eventhough im looking to build a set of MTMs cabinets, i would perfer to have a tall, deep, thin box for them. and i would perfer ported. looking at the freq responce of the DC160, it does have a smoother roll off in the upper end. i was also looking at the Dayton RS150S-8 6" Reference Shielded Woofer, but it gets kinda nasty in the top end too. ok then the Dayton DC160S-8 it is. but how big and what tune??
 
#5 ·
... perhaps i should stated that eventhough im looking to build a set of MTMs cabinets, i would perfer to have a tall, deep, thin box for them.
...
huh, looks like bassbox pro 6 has them in there. .75 ct ft a 32Hz looks nice.
...
So do you mean 0.75 cubic feet total, or 0.75 cubic feet for both? If the former, I think you'd have a tough time making a tall thin cabinet with that little space, unless you block off half or more of it. For example, your width will need to be about 8". Say by tall you mean 36" (average for the type of speaker you describe). 0.75 cubic feet is 1296 cubic inches. 1296/36/8 = 4.5" deep! I don't think that's what you had in mind. :) I was thinking more like 8" wide by 14" deep x 36" high. That gives you 8 * 14 * 36 = 4032 cubic inches = 2.33 cubic feet. Note these would all be internal dimensions, reduce by 1.5" in each dimension if using standard 3/4" thick walls. Anyhow, 2.33 cubic feet would give you much more extended low end. Tune to 30 Hz, and you will be down only 3dB at 30Hz. Myself, with that large an enclosure, I'd probably tune to 20Hz, to keep group delay much lower in the 25Hz and up range, plus you'd get a lot more output at 20Hz (though less from 30-50Hz).

Don't think you have to be forced into using the Dayton woofers, though. There are a lot of good woofers out there. The DC160-8 I think is one of the best values around, though, and I'm all about value. It also comes in shielded, if you want that, as the DC160S-8. That's what I'm using, but for all intents and purposes, they're the same.
 
#6 ·
I might be missing something, but I'm assuming that you're not building from a kit.. have you already bought the drivers? If you haven't, I'd look into some of the kits that are already out there. There is a lot that goes into building a sucessful speaker, and I'm worried you won't be happy with the results after your build. In particular, using a stock crossover may not give you the results you're looking for. They don't take into the varying impedences of the speaker drivers at different frequencies.

One place I'd take a look at is zaphaudio.com. He has several moderately priced designs on this website. I'd also take a look at the kits from Madisound and Zalytron.

Other speakers that you might look for are the Modula's and Natalie P's. Those two have had a realtively high level of support in the DIY community. Not sure what the current favorite flavor is.

Just my $0.02.

JCD
 
#7 ·
I completely agree with JCD. While I think it's entirely possible to build your first speakers from scratch, picking your own drivers and crossover, it still takes a fair amount of research and reading at a minimum, to achieve a good result - though some drivers are more foolproof than others (the Dayton I'm using being one of the more foolproof). I'm using mine with a Morel MDT-12, also available at Parts Express, a great little tweeter which takes well to a simple first order crossover.

But if one has no experience whatsoever, going with a kit all but guarantees you a great sounding speaker, at very little extra cost, if any.
 
#9 ·
Gotcha.. ~$200 for an MTM is a little tough to find, but not impossible. I don't think Madisound or Zaltron have MTM's in that price range.

However, Parts Express has at least one kit that uses the woofer you choose -- Link. It's currently out of stock, but the price listed includes the cabinets -- you can just buy the parts though (go to the manual for a parts list). I'd think your chances at a good build would be better going with this rather than a stock crossover and trying to figure out where to set the crossover (e.g., 2500hz or 2000hz or...). Anyway, the part list is probably within your budget.

JCD
 
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#10 ·
i would love to replicate this kit into my aplication. basicly find out the net air space/tunig as well as what type of Xover order etc... its says the Xover freq is at 2kHz, the only thing that suxorz is that it has a 4ohm final load. that amps im looking at, like most home audio is rated at 8ohms, and can go as low as 6ohms.
 
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#11 ·
playin around with Xover pro tonite. came up with this. all of the driver values are from the database

the one with the funky spike is actuly the 6.5" dayton classic. the other driver is the 7" aluminum cone. both use a 2nd order XOver at 2000Hz

 
#17 ·
I think even going the used route, a separates path is a little too pricey for a budget 2.1 setup. I'd stick with a receiver that can handle the 4ohm load. And I agree with Aaron, going with a full blown HT receiver like the Onkyo makes the most sense to me. I would think the Onkyo 605 would work fine as well. It can be had (refurbished) for $250.

JCD
 
#18 ·
According to the back panel, the Onkyo 605 specifies a minimum of six ohms, which is why I said starting at 705/706. That said, the 605 may handle four ohms just fine. My last receiver, a Kenwood VR-5090, also specified a minimum of six ohms, but was perfectly happy with four ohms all around. This is where the forums come in really useful, because the manufacturers will rarely tell you that their unit will handle anything other than the factory specifications.
 
#22 ·
...also im at a bit of a cross roads between a full 5.1(im not into 7.1, at least not yet) or just 2.1. looking at my living room, it would be difficult to do a surround sound, but when the basement is finnished thats a whole other story. perhaps i should spend the money on a good 2.1 receaver (if such a monster exist) then a ok 5.1 receaver. when the basement is finished and the "home theater" goes down there, i can always upgrade
There's nothing wrong with going 2.1 for now and getting a 5.1/7.1 receiver later. As I mentioned before, there are several inexpensive stereo receivers with subwoofer output (which I guess you could call 2.1 receivers) that fully support four ohm speakers. Of the ones I mentioned, I don't think I'd shy away from any of them. I myself would pick the Onkyo just for the front preamp-outputs in addition to subwoofer output, but if that's not important, any should be just fine. In my experience, Yamahas have always been a bit more reliable than Denon or Onkyo, but in general, stereo receivers tend to be much more reliable to begin with. If you really want to go with a full surround receiver which supports four ohms, you may want to look into used units or reconditioned units. Lots of people have upgraded lately to get the latest and greatest HDMI or high definition this or that.

http://www.yamaha.ca/av/PDFs/Receivers/2008_Models/HTR6130_Manual.pdf

it has a 4ohm rating (pg 66), but im unsure if its recomended to run a 4ohms i think this would fit the bill, as its afordable, and a good name
Eh, page 66? The owner's manual only goes to 64! After that you're in the appendices, which don't mention anything about speaker impedance. Moreover, on page 54, it specifies that you can use either speakers with eight ohm minimum impedance, or six ohm minimum impedance, depending on your selection in the setup menu. In the past, Yamaha surround receivers, even inexpensive ones, have typically supported continuous use of four ohm speakers in at least the front L/R channels, but this seems to not hold true at all anymore, even for many of their more expensive units.
 
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#26 ·
you said it. i think i may do zaph SR 71, and add a woofer later. ill model the sub accordingly and build the TMW towers, with a serperat chaimber, and add the sub/port/amp later. and u can bet ill post the build log up
 
#27 ·
Looks good to me! I've actually looked at that design for a friend of mine. I decided to try to build something from scratch, but that probably would have been my first kit choice given his budget.

When you add the woofer, how are you going to direct a signal to it? Will you redesign the crossover?

JCD
 
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