Dayton RS100S-8 Project, Help Needed!

[FiveEleven]

Hiya.

So I'm very new at this, and recently built a pair of speakers for my computer using the Dayton Reference RS100S-8 4" full-range driver. This was my first attempt at speaker building. I ended up with a sealed enclosure, around .09 cu. ft. or so, lightly stuffed. They sound fairly decent, certainly better than the JBL Creature 2.1 system they're replacing, much more presence and detail, but lacking in bass, obviously as I haven't built a subwoofer for them yet.

Here is a picture of them, the cabinet is 9x5x6 (HxWxD). Click the picture because the thumbnail is cutting off the sides for some reason.


After building them, and listening to them for a bit, I've decided that they could probably use a tweeter to help out on the highs, and since I wasn't particularly thrilled with how the spray paint finish turned out, I am going to completely rebuild them. Here is where I need the help of people who actually know what they're doing. I am not particularly adept at woodworking, I do not own any woofer testing equipment, and I don't yet understand the fundamentals of how the TS parameters work together or what they really do, etc. Nonetheless, I enjoyed building them and want to continue with this project.

So... I'm not really sure that a sealed enclosure is the best choice for these drivers, and in any case, I want to add in another RS100S-8 per speaker and also a tweeter that I haven't picked out yet, but probably one of the cheap Dayton Audio neo tweeters.

I will be using 1/2" MDF and have the internal dimensions as follows:
13x5x5 inches, HxWxD. This gives me roughly .188 cu. ft., not taking into account driver displacements. I am having a tough time calculating port sizes, as I just don't understand how all the variables mesh together to create the end result, or what frequency to tune it to, the Port Q, etc. I am using [bumbling around in] Speaker Workshop.

I am hoping someone knowledgeable here would be willing to model a vented (or sealed, if that's the best option) box for me, and I can just take the data and construct the box. I would really like to keep the dimensions I've chosen, as they will be sitting on the sides of an LCD monitor and are already approaching a ridiculous (relative) size. I do plan on building a subwoofer for this system in the future, probably crossed over around 150Hz or so to take the strain off the small 3" drivers, so the bass response isn't too important. All my modeling is showing a 2-3 dB bump in output from ~450Hz down to ~120Hz or so, and I'd really like to get that flatter so the midbass isn't overpowering.

I do have that same bump in the sealed enclosure they're currently in (according to Speaker Workshop), so maybe a notch filter or something similar is in order, I don't know.

The specs for the Dayton RS100S-8 driver are as follows:

Impedance: 8
Re: 6.3
Le (mH @ 1KHz) 0.41
Fs: 85.0
Qms: 3.48
Qes: 1.16
Qts: .87
Mms(g): 3.9
Cms (mm/N) .98
Sd(cm2): 37.4
Vd(liters): 13.1
BL(Tm): 3.40
Vas(liters): 1.7
Xmax(mm): 3.5
VC Diameter(mm): 26
SPL: 83.3
RMS: 30w
Useable Frequency Range: 85-20000




If anyone out there is willing to help me or give out some pointers, it's appreciated. If you wanted to go the extra mile and help me design a crossover (saving me from using the pre-built ones) that'd be amazing. I appreciate the time, thanks in advance guys!

[croat47]

There is a thread in the Full Range forum...

Dayton RS100S-8 4" Reference Shielded Full-Range Drivers?

[sdclc126]

Don't use a vented enclosure with small woofers - you need a larger enclosure and the bass gains will be negligible. Stay sealed and use a sub.

From Zaph Audio: "Could be used full range with a breakup notch and a shelving BSC filter, but would be even better paired with a cheap neo tweeter." Maybe the easiest/cheapest way to go is to flatten the breakup but otherwise let it run fullrange and then see how it sounds. If you want to add a tweeter try something like:

http://www.partsexpress.com/pe/showd...number=275-030 and cross over at 3500 or higher - go higher and use a single capacitor.

The existing cabinets are probably fine - if you can flip them & remount the bases just install the tweets right above the woofers.

Also - great way to learn and then do it all yourself:
http://www.rjbaudio.com/Audiofiles/FRDtools.html

[FiveEleven]

Thanks for the response croat47. I read that thread several times before I built these cabinets and it's of zero use. Unless I missed something, it's mainly a bunch of people from the Bigger Is Better school of Full-Range design that suggest floor-to-ceiling sized cabinets for this driver, trying to get bass response to 40Hz with this driver, Open Baffle or Open Back (OB) discussion, and other ridiculous (to me) nonsense that has no bearing on what I hope to accomplish.

Originally posted by sdclc126
Don't use a vented enclosure with small woofers - you need a larger enclosure and the bass gains will be negligible. Stay sealed and use a sub.

From Zaph Audio: "Could be used full range with a breakup notch and a shelving BSC filter, but would be even better paired with a cheap neo tweeter." Maybe the easiest/cheapest way to go is to flatten the breakup but otherwise let it run fullrange and then see how it sounds. If you want to add a tweeter try something like:

http://www.partsexpress.com/pe/showd...number=275-030 and cross over at 3500 or higher - go higher and use a single capacitor.

The existing cabinets are probably fine - if you can flip them & remount the bases just install the tweets right above the woofers.

Also - great way to learn and then do it all yourself:
http://www.rjbaudio.com/Audiofiles/FRDtools.html

I made the purchase decision based upon the review I found of them on Zaph Audio. Originally, I wanted to use a tweeter, but I felt overwhelmed designing a crossover for them. So far everything I've read on various forums and other places suggests that the pre-built crossovers, like the ones sold at PartsExpress are garbage and I should always design my own. Can you shed any light on this?

I also read where Zaph recommends never to use a vented enclosure for these size drivers, but elsewhere I've noticed many designs using similar small drivers do. I think I will stick with sealed though.

My biggest issue I think is a lack of confidence. I'll read how to do something on one site, and then read on another site you should never do what the first site said, and for me, since I'm still trying to grasp the fundamentals here, it really just spins me in circles.

I have way too many questions to even ask here, so I'll check out the link you gave me. The one thing I would like to ask though, in Speaker Workshop, when I modeled the sealed cabinet they're currently in (~.09 cu ft.) there's still that hump from ~120Hz - ~500Hz, which peaks at +2.14dB around 160Hz. This hump didn't really disappear until the enclosure size was increased from .09 cu ft. to ~.75! cu ft. Obviously, that's a ridiculous size for computer speakers. Should I just ignore this, or what? Granted, it's only modeling, but without measurement equipment it's the best I have to go off of. To me, I *think* I'm hearing something wrong in that frequency range when listening, something just doesn't sound right, and I can't determine whether it's my imagination (since I know the hump is there in the model), or possibly the fact that they are being run full-range without a sub and their efforts in trying to recreate bass below their capabilities is causing distortion or, hell, I don't know.

Thanks for the responses though guys, it's appreciated.

[Godzilla]

>>> it's mainly a bunch of people from the Bigger Is Better school of Full-Range design that suggest floor-to-ceiling sized cabinets for this driver, trying to get bass response to 40Hz with this driver, Open Baffle or Open Back (OB) discussion, and other ridiculous (to me) nonsense that has no bearing on what I hope to accomplish.

LOL! I suggest leaving these in the sealed enclosure, adding a tweeter if you feel it needs one and building a powered subwoofer.

You could try making that box aperiodic but i have no clue how much difference it will make.

Otherwise, the driver is best suited for an open baffle design that will be wider than you want. But that will most likely give the best result with this type of driver based on its specs.

Tangband makes small full range drivers similar to the one you chose that work better in small sealed boxes. I would also suggest trying those, the 871 comes to mind but there are others.

http://www.partsexpress.com/pe/showd...number=264-813

These new Dayton full rangers are new drivers and have not been used in many projects that i know of. That may be why there is some confusion about which type of cabinet they work best in.

Enjoy the building process.

[sreten]

Hi,

2.5 litres well stuffed is a good choice, 4L effective is as far as you
need to go. Vented is not a good choice for a planned subwoofer.

With a PC you can EQ out the treble peak, experiment with EQ'ing
up the bass end below 100Hz, and tilting the overall response.
With so many PC plugins available ... try a 31 band graphic EQ.
And a 1/3 octave pink noise generator .... or recorded bands ....

Does your modelling include the baffle step ? You may find you
effectively have a midband dip followed by too hot upper midrange.

There is a lot you can tell with your ears and the right tools.

I do not think nearfield you need extra main drivers, tweeter perhaps.

/sreten.

[Kensai]

Just build your planned enclosure as a sealed box with the ability to easily remove/replace the back panel. My initial test baffles for these driver were folded cardboard that were of similar size and shape to what your boxes would be without their back. With no EQ, that gave be good response down into the 70s. I've not tried them in boxes, but on OB, I'm not having any problem with hot mids, treble peaking or anything missing off the top (these are the only drivers, ever, that I've been able to repeatably hear test sweeps up to 20kHz; though I was basically deaf above 16kHz up until I tested these). On OB, these drivers sound clear and pure and are only missing the bottom 1.75 octaves. One note, for material with heavy bass content (DVD, dance/electronica, some orchestral pieces, etc.) the RS100S-8 on OB can be driven to distortion, even with no EQ (I don't use EQ anymore since I've got a Dayton APA150 amp that gives me basically a stereo sub amp with active crossover), so perhaps a bit of highpass crossover at 80Hz or higher would be helpful (something active would be my preference).

Make sure and share what you come up with and let us know how it sounds.

Kensai