Next set of bargain 2-ways

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Re: This be what you want

cyberspyder said:
I've just completed the Zaph Bargain Mini's and would like to commence a new build. Only criteria is that the woofer has to be bigger than 4" as one of the shortcomings with the ZBM4 was the lack of lower frequencies I would still like it to be a 'bookshelf' design...maybe something like this: http://www.htguide.com/forum/showthread.php4?t=24504&highlight=bosebuster ?
You can build these for $95 for all the parts!!! They were pretty well-received at Dayton DIY 2008.
http://undefinition.googlepages.com/diy-orientexpress


Or, I just put together this project for my brother in law. If you want a lot of low-end extension, this should do the trick for under $150. :
http://undefinition.googlepages.com/diy-classix
 

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OK, so a sub should be on building list...problem is, I know nothing about them...did some searching, ended up with this: http://s18.photobucket.com/albums/b117/wolf_teeth_speaker/Triumph/

May I ask what Zaph meant by Now if you do need more output, you will need a subwoofer and the two LR4 power handling charts should help you select an initial crossover frequency . After that, let your ears do the tweaking. If low bass content seems to cause mid bass grunge from the minispeakers, your sub crossover frequency is likely too low for your preferred listening level.

What is crossover frequency and how do I 'set' it?

Thanks, Brendan
 
The crossover frequency is simply the frequency at which you set the subwoofer to take over the bass frequencies; most subwoofer amps have an adjustable knob to set the low pass crossover frequency.

Ideally, you would have a high pass filter on the ZBM4's amplifier, and you could set that to cut off the low frequencies to the ZBM4s. This allows you to get higher output levels from the ZBM4s (because they don't have to play as low and won't run out of excursion).

If you don't have an active crossover or filter setting on your amplifier, then you could just stuff the ports and tune the subwoofer to the natural acoustic rolloff of the resulting sealed enclosures. From the look of Zaph's page, the frequency you would set the subwoofer crossover to in this scenario is around 80Hz.

This is a grossly oversimplified summary, you owe it to yourself to keep reading so that you better understand how to set it up.

-David
 
The best deal on a subwoofer amplifier right now is the 100W module at MCM. http://www.mcmelectronics.com/product/50-6272 . The advantage of this module over the PE 70W one is that it has adjustable phase, where the PE one does not. It is also much more powerful (though you aren't likely to need the extra power with an 8" sub).

With a catalog code ( you can use mine 8HTC15 ), you can get one for $66.00 + shipping. They have some decent 8" subwoofer drivers as well. Zaph built a sub using the 55-2185 that he liked alot. It's on sale for $21.95 (use same coupon code as above).

There is also the 55-2421 8" subwoofer that is a great deal at $24.95 ( use coupon code WA807 ).

Subwoofer design is easy and fun; you could design a box yourself with a little effort. Alternatively, both of the above woofers should have box plans available on the internet.

-David
 
My :2c: ; If you are not going to go all out with something like a big tapped horn or infinite baffle your best chance for success is to get the biggest driver you can handle with some decent Xmax and a Qts of around .4 and put it in an appropriate sealed box with a nice plate amp.

This approach is simple, forgiving of errors and capable of very nice results in most listening rooms. For a normal listening room I would shoot for at least a 12" with fs in the 20s. My "Fireplace" sub gets along fine with 6mm Xmax but it is rather borderline. My room not teribly large and has a room mode at about 40Hz. In a larger room I would want more Xmax. I am using a 120W /4ohm (My sub is 8 ohms though) and I have not noticed a lack of amplifier power.

I don't get too thrilled by the traditional ported enclosure for the most part as the sealed box rolloff fits the typical room gain better and unless tuned quite low is not so nice at its lower limits. If I already had a low Qts driver that wouldn't work too well in a tapped horn I might take a stab at a low tuned (extended bass shelf EBS) ported enclosure but would not be my first choice.

Ease of success is an important parameter for first project I think. Just MHO.
 
diyAudio Member
Joined 2007
Triska sub looks nice but if a small budget is prime then go 2 small sealed using any reasonable 8inch driver, then youcould get a cheap stereo amp from a garage sale to run them.
That would mean you would need to use some extra electronics to split the signal but I understand you may not want the extra complication
 
I don't know how set you are on building your own sub, but right now there are two very good (and inexpensive) options for preconstructed powered subwoofers.

One is the 10" 100W powered sub at MCM. Using the 8HCT15 coupon code this subwoofer will be $80.95

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The other is the 10" 125W powered sub at Parts Express. This subwoofer is on sale for $110.86.

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For buyers in the continental USA, shipping on either is free this weekend (up to 9/4/08 for MCM). Use coupon code EMC070 at MCM, you must purchase something from the clearance section to get the free shipping (there are several cheap items that cost less than a dollar).

Just a heads up.
David
 
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