Advice welcome; makin speaker boxes

C

ClemS

Audiophyte
Hey all, I've caught the DIY bug, and I'm planning on building a pair of 2.5 way tower speakers. These will be for a stereo for now, but will hopefully be integrated into a home theatre as fronts in the future.
My plan is to make them look something like these: http://www.partsexpress.com/projectshowcase/eros/Vifa023.jpg
But with dual 8" subs, ports on the front, near the bottom.
I'm thinking of using the following components:
Subs

Tweets

Crossover

What does everyone think of Dayton drivers? And the quality of the crossover I posted?
I've mainly done work in car audio, namely in installations, so home audio is relatively new to me. My main reference for home speakers is a pair of old Boston Acoustics A60s that I've had for years, which use an 8" woofer and tweeter. I've always thought these sounded good, but they're wearing out and I'd like something louder.
Also, is there a rule of thumb for the distance CTC for mounting dual woofers? What about tweeter mounting? I've mainly seen DIY speakers with the tweeters mounted off center, and I wasn't sure if this has some advantage. :confused:

Any comments or advice is appreciated!

PS. Does anyone know if it's a good idea to order from partsexpress.com if I'm in Canada?
 
Swerd

Swerd

Audioholic Warlord
ClemS said:
My plan is to make them look something like these: http://www.partsexpress.com/projectshowcase/eros/Vifa023.jpg
But with dual 8" subs, ports on the front, near the bottom.
I'm thinking of using the following components:
Subs

Tweets

Crossover

What does everyone think of Dayton drivers? And the quality of the crossover I posted?
I've mainly done work in car audio, namely in installations, so home audio is relatively new to me. My main reference for home speakers is a pair of old Boston Acoustics A60s that I've had for years, which use an 8" woofer and tweeter. I've always thought these sounded good, but they're wearing out and I'd like something louder.
Also, is there a rule of thumb for the distance CTC for mounting dual woofers? What about tweeter mounting? I've mainly seen DIY speakers with the tweeters mounted off center, and I wasn't sure if this has some advantage. :confused:

Any comments or advice is appreciated!

PS. Does anyone know if it's a good idea to order from partsexpress.com if I'm in Canada?
You're thinking of making a number of changes to what seems to be a well thought out design. Why? Your changes may not work as well as you intend them. I see several potential problems.

The original design uses two 7" woofers. You want to use 8" woofers instead. The cabinet volume and port dimensions will probably have to change if you want the best bass response from your woofers. Instead of redesigning the cabinets for the 8" woofers, why not stick to the original 7" Vifas? They're not too shabby, and I think they will produce powerfull bass in a cabinet that size.

The Vifas also have a smoother high frequency response than the 8" Parts Express aluminum woofers. Those RS series woofers are new products and are getting a lot of attention from DIY builders. They seem to have a number of good features and are not very expensive compared to some other aluminum woofers. But the high frequency response above 2,000 Hz is a mess. See the graph http://www.partsexpress.com/pdf/295-366g.pdf. You may have to filter out that breakup noise with a steep crossover roll-off curve. I'm not sure the 2nd order crossover you want to use will be enough with a roll-off of 12 dB per octave. If you use a steeper roll-off, say 24 dB per octave (a 4th order crossover), you may find that the 2-way combination of 8" woofer with 1" dome tweeter lacks response in the critical midrange frequencies around the crossover point. The sound will have a hole in the middle. This is another reason to stick with the 7" Vifas.

The original design came with a custom designed crossover. Why not use it?
http://www.speakerbuilder.net/web_files/Projects/Eros Project/mk2final.jpg
It has a much better chance of sounding better than the stock crossover. If you have never built a crossover, read this http://www.speakerbuilder.net/web_files/Articles/constxo/xoconst.htm.

Finally, you have switched to a different tweeter. It is much less expensive, and unlike the Scan Speak, is available. Of all the changes you're thinking about, this one may work OK. Go ahead and try it.

I don't know if shipping to Canada is a problem for Parts Express. Ask them. Solen is located in Canada http://www.solen.ca/, but they don't sell Dayton speakers.

I don't want to discourage you from building speakers. The original Eros, or the updated Eros II design may be great. I say, if it ain't broke - don't fix it! The best thing someone new to DIY speakerbuilding can do is to copy a proven design. Hope this helps.
 
gregz

gregz

Full Audioholic
GREAT response, Swerd!

Besides agreeing with everything Swerd said, I'd like to emphasize the difficulty of getting the crossover right. After all the math to get into the ballpark, it involves a LOT of tweaking to get the rest of the way there.

I too have looked at MTM designs and been disappointed in the poor low end bass response compared to a 3-way design. But upping the size of the woofers is really not an option, because good midrange depends on the woofers staying on the small side.

The only solutions to the problem of an MTM design not being loud enough or not having enough low end bass are:

1) Go with a 3-way design instead of MTM
2) Go with a proven design and add a powered subwoofer to augment the MTMs.
 
C

ClemS

Audiophyte
Changing the plans

Omg, I can't believe I just typed this response, only to hit "Preview post" and have it disappear. Does this feature work for anyone else?

Anyway, here I go again.

First, thanks for the responses. I don't feel discouraged from building speakers; I expected there was much more to the design than what I was considering.

Swerd said:
The best thing someone new to DIY speakerbuilding can do is to copy a proven design.
I seem to keep reading this over and over on DIY sites, and it’s finally starting to stick. I agree, the best route for me is to use a design that has already shown success.
I do like the Eros/Eros II design, but I realize now that it’s a bit out of my price range. $63 each for 4 Vifa woofers, add tax, shipping, and the exchange, and I’m not eating for a while [in college]. The Dayton III project is now under my consideration. I know these aren’t towers like I said I wanted at the beginning of this thread, but I’m not fussy about the size or how much space they use as long as they perform. These speakers use smaller woofers than what I had originally planned, but from the design notes: “The D3's produce unparalleled depth in the bass region, obviating the need for a subwoofer” I think these 6.5”s may suffice. What do you guys think?
Could I make the exact setup of this project, but install it in larger cabinets for better low end extension? I want them to have good bass response, but I don’t want the bass to become muddy or worry about ‘bottoming out’ the woofers.
Should I forget thinking of ways to modify this project and just build exactly what is on the site? If you think so, just tell me. I’m new at this :) .
Also, if you can recommend any similar projects, please post them up.
Thanks again
 
WmAx

WmAx

Audioholic Samurai
ClemS said:
These speakers use smaller woofers than what I had originally planned, but from the design notes: “The D3's produce unparalleled depth in the bass region, obviating the need for a subwoofer” I think these 6.5”s may suffice. What do you guys think?
I have never heard or measured the DIII. However, I have a friend of which I hold in high regard and has auditioned many of these popular DIY units. He did not find the DIII to be a good value if realistic presentation is desired. He suggested that one of the best low costs designs he had used as far as a realistic presentation was by Darren Kuzma; the project can be seen here:

http://www.partsexpress.com/projectshowcase/exmonsters/exmonsters.html

The Ex-Monster project certainly uses much higher quality drivers then the DIII. But, I do not personally endorse any of these speakers.

Note that (1) You will have to track down discontinued drivers [and] (2) You would need to use subwoofers with the Ex-Monster if optimal performance was desired. However, at least you should have a very high quality midrange/treble module to begin with. You can always add low frequency abilities with a 2 way active crossover in the future.

Also, while I provided the link above, I repeat that I do not endorse any part of it, especially not the various *bull* that is spewed about crossover parts, etc.. However, it is important to note that such unsubstantiated *beliefs* are seemingly widespread -- but I have to make sure that I am clear in my endorsements.

-Chris
 
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Swerd

Swerd

Audioholic Warlord
ClemS said:
Could I make the exact setup of the Dayton IIIs, but install it in larger cabinets for better low end extension? I want them to have good bass response, but I don’t want the bass to become muddy or worry about ‘bottoming out’ the woofers.
Should I forget thinking of ways to modify this project and just build exactly what is on the site? If you think so, just tell me. I’m new at this :) .
Also, if you can recommend any similar projects, please post them up.
Thanks again
I was thinking of mentioning the Dayton III as an alternative in my previous post, but that post was getting plenty long, and it seems that you already have thought of it. Good. The price is probably as low as you can go with a reasonable MTM design. And yes, I think you should build it exactly as Wayne J designed it. Resist that urge to improve and modify - at least for now ;) . If all you want is some good speakers at a great price, you will have it. If you do have the DIY bug, you will probably want to tinker and modify, but you have to begin somewhere. You will find that it can be very difficult to improve on such a design and keep the price the same. Many others have learned this the hard way.

As far as bass response goes, remember that two 6½" woofers will move twice as much air as one, but their lower frequency limit will still be the same as for one woofer. The free resonance frequency (Fs) is 33 Hz for that woofer is an unchangeable fact. But with double the capacity to move air, the Dayton IIIs will sound more powerful in the 50-100 Hz range than a 2-way with the same woofer. If you try a larger cabinet, you might get a bit more bass at the expense of less midrange performance (I'm guessing here). A speaker can only deliver so much acoustic energy. If you adjust things to get louder bass, it must come with the loss of energy somewhere else in the audio spectrum. If you really must have more bass, a subwoofer just might be your next DIY project. Good luck whatever you do.
 
cbecker33

cbecker33

Audioholic
Swerd said:
If you really must have more bass, a subwoofer just might be your next DIY project.

I second this idea. My first DIY speaker is a sub, and I have to say it was fun and fairly easy. Sorry, but I'm not going to put a finish on it until I move into my new place!
 

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ClemS

Audiophyte
Other options

Mmmmm, altoids. That sub looks slick.

Thanks again for the replies. Right now I'm in the planning stage, and I'm eager to begin fabrication of whatever design I choose in the spring. The DIII's are definitely a candidate.
Another design I discovered today is the Dayton 8. I've read that these speakers will produce mad bass, but perhaps lack some performance in the midrange. Now, I'm more or less an average listener, and I've never owned any particularly 'great' equipment, so would I notice this? I am a fan of bass.
I'm just trying to gather some info about a couple of different projects, so I may very well go with the DIII's and build a subwoofer later. Feel free to give me any opinions. :)

Dave's Dayton 8
 
S

SQ Kid

Audioholic Intern
i'm looking to do an all dayton ht speaker setup. most likely gonna do the D3 as the center (toss up now for fronts vs the dayton 8), and wayne's dayton budgets for the remaining surrounds (not sure if i'll do the 6.1/7.1 speakers yet). seems to be around $230 for all the raw drivers to do a 6 channel setup, which aint too bad. the crossovers may be a hefty chunk too, but this should rival setups 2-3x the cost
 

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