How low can you go

I have an old but reliable Onkyo dvd/integrated home theater receiver that does sole TV duty. I don't think this qualifies as "home theater" so much as the box that has the dvd player and amplifier for 5.1 speakers. The 5 paper/foam surround speakers are starting to rot and they never sounded all that good in any event. The sub is a Yamaha with a synthetic cone and is in good shape.

We are not much into movies or tv and it has been good enough. However, the speakers really are rotting, literally, and I went to Madisound to see what inexpensive full range options I might not know about or to see what the FE103's or FE123's and CHR-70's were selling for.

There is a brand of speaker that is changing its business model and selling off their current commercial units. There is a blue light special on the $24 Aurasound NS4-255-8A 4" Full Range now selling for $3.90. I need to buy 5 units and the only sound sources are DVD's or cable through a 30watt Onkyo.

Does anyone have any experience with this ostensibly full range speaker? I was not going to go any higher than the CHR-70 as my top of this line anyway. For $20 I can get 5 of the Aurasounds and for $180 I can get 5 CHR-70's. Thinking amortization over 5 years this does not represent much problem. But, if I can get away with spending only $20 for a system that I don't consider a "system" then "it's all good." The most demand on it will be the kids who run their game systems through it. But this happens less then a couple hours a week total because I am a mean and uncool father who limits such things in favor of sports and homework. I hear myself talking me into the Aurasounds unless they really are dreadful and a waste of the time/money it will take to construct the cabinets for them.

Feedback is welcome and invited on the speakers. I am refractory to commentary on my parenting or lack of investment in home theater.
 
At $19ea from Parts Express you might want to consider the Pioneer B20 'BOFU'. They are quite popular and there are several proven cabinet designs and tweeks available. I'm building some half-changs for them at the moment. At 8" they may be a little large for the surrounds but maybe you could play with the Aurasounds for that apt. They too have foam surrounds but I understand that lightly coating them with grout sealer will help prevent deterioration.
 
Now this is what I am talking about:

Resonant Frequency (Fo) - Fs . . . . . 105 Hertz
Voice Coil DC Resistance - Re . . . . . 6.8 Ohms
TotalQ-Qts ..................0.56
MechanicalQ-Qms ............6.90
ElectricalQ-Qes ..............0.60
Equivalent Volume of Air - Vas . . . . . 1.85 L
Radiating Piston Area - Sd . . . . . . . . 50.27 cm2

In thinking about cabinets my first stop is usually the BIB xls because I don't have access to the Quarter Wave xls. BIB xls asks a reasonable question like what is the Fs and this specs 105 Hertz. Is this actual or am I missing something? What is this addition to the Resonant Frequency, the (Fo), in (Fo)-Fs? Looking closely more closely at this unit it is not all that Full.

Am I correct that it will be quite limited below 100hz and I see it goes up to 15khz. Seems a bit narrow for all the work of constructing cabinets.
 
Another suggestion for you. Check out planet_10 hifi if you haven't already. There are numerous plans for chr70 mains as well as a designs for centers and surrounds for HT. Not that I want to discourage you from experimenting and having fun but I'd be afraid of wasting time on those Aurasounds. If you want to bump up the quality even more, Planet10 has the EnABLED chr70s on sale for December. You could get a pair of those for the mains and go stock everywhere else. Then if you ever wanted to upgrade the rest of your system you'd be ready.
 
CIB

Talked myself back into the Cheaper is Better mode and ordered the $3.80 drivers. And I goofed earlier when I entered the parameters for the Aurasound NS4-255-8A 4" Full Range into the BIB calculator by forgetting to convert liters to cubic feet.

My values are Fs 105, VAS .065, and Qts .56.

These will be Lilliputian BIB at 6.5"x8.5"x33", cute as buttons.

I could always make something that looks like a shoe box with a toilet paper roll stuck in it, which is the back up plan, but I have long wanted to try my hand at this BIB design.

Of course I have no rational basis to consider the appropriateness of this cabinet for this speaker and if this is folly I would sure appreciate some forewarning. I will be spending more on glue than the drivers which came to under $30 for 5 of them shipped.

The paper whizzer and rubberized paper cone gave me some pause when something metal would likely suit the home theater genre better, but I am not much of a car chase explosion kinda TV/movie watcher.

Tomorrow I will hunt down the repository of knowledge associated with BIB. But this is enough hobby for one day.
 
Last edited:
I am thinking if the BIB is too diminutive then an Alphorn adaptation might be the ticket. I found an updated example. I understand they play until the cows come home.
 

Attachments

  • 220px-Bardentreffen_2009_2169.jpg
    220px-Bardentreffen_2009_2169.jpg
    11.3 KB · Views: 130
Hi,

Noting you will still need the subwoofer there is not point going exotic
on the cabinets, especially five of them, for no real useful purpose.

The drivers are good value, and IMO with a typical AV crossover all
you need is 4L boxes tuned to 80Hz, anymore is IMO pretty silly.

Large BIB's are IMO farly pointless with AV crossovers at work.

rgds, sreten.

You could do a lot worse than 5 of these :
http://homepage.mac.com/tlinespeakers/FAL/downloads/mFonken-1v1-map-270509.pdf
 
Last edited:
Hi,


The drivers are good value, and IMO with a typical AV crossover all
you need is 4L boxes tuned to 80Hz, anymore is IMO pretty silly.

Large BIB's are IMO farly pointless with AV crossovers at work.

rgds, sreten.

You could do a lot worse than 5 of these :
http://homepage.mac.com/tlinespeakers/FAL/downloads/mFonken-1v1-map-270509.pdf


I think you are correct on all counts.

My thinking about the BIB was that they are floor standing which eliminates the need for stands that I would otherwise need and they are pretty simple to construct. Also there is a pretty good calculator whose results are fairly forgiving and easy to tweak after assembly.

I have some Fonken167's for my real music on the very short list of projects these coming months. I do like the cabinet you shared and had only remembered the side vented Fonkens. So thank you for reminding me of this puppy. I don't recall if there is a "calculator" for this cabinet.

I do know the FE127, and this Aura ain't no FE127. But I think it would be easier to tweak this bottom slot cabinet than the side vented Fonkens.

This Aura driver in a 0.1 cubic foot sealed box has an F3 of 150Hz and in a cabinet of 0.1 cubic foot with 1" diameter vent by 1.75" long an F3 of 90Hz.

I need to find one of those calculators that give tube vent/slot vent equivalents and my box should be about 3 liters (room for internal bracing).

But this sure beats the shoe box I was contemplating.

Thanks for the suggestion.

Bruce
 
Ok, I see. That works! Besides, my kids are entering high school and we have scads of old silly paper back books that make excellent ballast. Some good T-nuts and quality neoprene makes it a snap to pop the driver in and out and change the volume and stuffing.

I was eying the den tonight watching the Disney Chronicles of Narnia with my daughter and I think the room would better manage smaller boxes after I experimented with trash bag sim's of the floor standing BIB's. Rather than floor stands I am going to cable down from the ceiling. It might be the season but ornaments, sound giving or not, seem to be "in."