Dayton RS100-4 Needle filter.

Status
Not open for further replies.
Jump to Latest
#2
It's probably a baffle step circuit. Typical ones for a speaker this size and RS100-4 would be to try a 0.8mH to 1.0mH in parallel with between 3ohms to 7ohms. You can add a 0.47uF to 2.2uF in parallel to boost HF's. Adjust values to taste. Start with 0.8mH and 5ohm see how you like it. It can be modeled of course if you have exact dimensions of speaker. I like the RS100 - nicely built and great sound.
 
#3
Thanks for the response! 0.8 mH is definitely what I saw in one of the pictures used as the coil. The write up says:
"Reporting on the crossover for a wide-range speaker is not an evening-long production. As a rule, it consists of three parts that are connected in parallel in the signal path. Their function is limited to balancing out the volume increase caused by reflections on the baffle board by way of a controlled increase in resistance. The RS 100-4 also required this type of correction, since its frequency curve shows a long bulge from 400 to 5000 Hz. Here we had to make a moderate intervention, particularly including the area around 3 kHz in the reduction. The ear is sensitive to any exaggerations in this range, which it perceives as annoying and bothersome."

Reading that again makes me agree that its a BSC. The speaker is 5" wide by 36" tall by 7.75" deep.
 
#4
big5hooter said:
Can someone please point me in the right direction to find out the filter parts for this build:

Needle - February 2013 - Loudspeakermagazine 2013 | Loudspeakerbuilding

I have tried every keyword I can think of at multiple forums and no luck. plenty of people have built these so the info is somewhere but it alludes me. Please help!
Click to expand...

Let's take a shot at it...The curve picture is very small, but from looking at it looks like the following:

According to the curve the rise starts in the 400 Hz @ 80 dB, then peaks at 2,000 Hz @ aprox. 87 dB, and it comes down back to aprox. 83 dB at 5,000 Hz, when it stabilizes until the frequency reaches 18,000 Hz where it rises again from 83 dB to a peak of aprox. 92 dB, and back to 80 dB at 20,000 Hz.

At a 3dB rise (83 dB) the lower frequency is 700 Hz, and the higher frequency is 4,000 Hz. The rise difference in dB's between our base SPL of 80 dB and the 87 dB peak in the mid to mid-upper range curve is 7 dB (87 dB - 80 dB = 7 dB).

We need to filter that rise, and in order to do that we have the info needed, which is:

Lower Frequency at an SPL Rise of 3 dB (f1): 700 Hz

Higher Frequency at an SPL Rise of 3 dB (f2): 4,000 Hz

Peak SPL Rise Differential (At): 7 dB

If you want to take out a calculator and do the math, the formulas are as follows:

Frequency Differential to Filter Hz (B): f2 - f1 = 4,000 Hz - 700 Hz = 3,300 Hz

Avg. Frequency Hz (f): B/2 = 3,300 Hz/2 = 1,650 Hz

Capacitance F (C): 0.03003/f = 0.03003/1,650 Hz = 0.0000182 F = 18.2 uF (microFarad)

Inductance H (L): 0.02252/(f2*C) = 0.02252/49.55 = 0.00045 H = 0.45 mH (milliHenry) *Note: f2 = f squared)

Resistance Ohms (R): 1/(6.2832*C*B) = 1/0.38 = 2.63 Ohms

Now you have your Resistor, Capacitor, and Inductor (RCL) Values:

Resistor: 2.63 Ohms

Inductor: 0.45 mH

Capacitor: 18.2 uF

Above are parts for what stores would call the BETTER filter...For other options:

Best: Resistor, Inductor, and Capacitor

Good: Resistor, Inductor, and Capacitor

Economy: Resistor, Inductor, and Capacitor

Anyways...Using a notch filter calculator is probably easier!

* Also, these is a scientific guideline, there is nothing like your ears, or, even better, a measuring mic with software.
 
#5
That would be the calculations, this is a Needle rs100-4 built pic

needle_frieder_6.jpg
 
#8
Wow! Thanks for all the info guys. Are we talking about a BSC or a notch filter? Are they essentially the same thing targeting different frequencies? Irribeo was there any commentary that said the values on the photo you posted?
Guangui, thank you for taking the time to do all that. That helps a lot. The guys that made the dayton needle had a mic and the software. Thats why it would be nice to know their exact values but if I can't find it I'll use exactly what you have provided. Thank You.
 
#10
The RS100-4 is intrinsically flat through the baffle step region so it doesn't have the built in "baffle step" shaping claimed by MA drivers. It will sound thin without BSC unless it is in a bass augmenting box like an XKi or K'nator. A MLTL has some bass augmentation but placing near a back wall may solve the lack of a BSC.
 
#12
irribeo said:
No comments, edited I guess, but you got all values now, 22uF, 2.7ohm and the inductor coil, just need to verify that coil was for Needle with Dayton rs100-4, oh values in kit might not be best, but they are original values LOL

my photo came from :

Frieders Needle - Ausgabe Januar 2011 - Lautsprecherbau-Magazin 2011 | Lautsprecherbau
Click to expand...

Not far off my calculations, if using a 22uF Cap, 0.18mH Inductor sounds about right, though it seems small, I believe something in the 0.4 to 0.45mH range should be correct. Anyways, like I mentioned in my original post, the calculations give you a starting point.
 
Status
Not open for further replies.
Top Bottom