New Design (in over my head?)

[NoNoBadDog]

I have been trying to come up with a design that makes sense. I think this one does so far but I am a noob so I might be in over my head. What I really want to know is if this one makes any sense. I have no way to measure drivers at this point. I am working on the microphones but don’t have them yet. I hope to have them within the next two weeks. If any of this sounds real out of whack please let me know. :E

Goal:
1. Reach a low as close to 20Hz as possible.

2. Maintain SPL of at least 91.5.

3. Use as little attenuation as possible.

4. Spend as little money as possible without really compromising any sound quality. (I know speaker design is a series of complicated compromises.)

5. Must be able to handle 140 watts RMS.. This applies to the tweeters more than anything. (So the wife won’t blow them up when she is cranking the stereo. Yes, she has turned the system all the way up on several occasions. (It might save her the awful experience of being strangled slowly in her sleep.) :twisted:

6. Try to keep the size down to something useable in my living room. My limits at this point are 24” wide, 24” deep and 50” high. Not sure that I can meet this goal. I have done some work with the measurements of the bottom of the case but haven’t worked on the one for the mids.

7. I want to stick to a 3 way but if it is necessary I can go to a 4 way. A 4 way would be hard to do with the previous goal of keeping the size within those parameters.

8. I want them to sound reely, reely gude.

Crossover points:
I want the high to be at around 3500 and the low at about 350. The high band can be higher.


Driver selection:
Tweeter:
I haven’t decided yet. I will work on that after the hard part of woofer/cabinet part of the project.

Mid Range:
3 Morel MW144 4” mid woofers (I am not sure of the quality of this driver since I am a noob and not had any experience with many types of drivers.) . Looking at the sheet from Morel it looks like the MW144 can handle it easily to 4000 and maybe even 5000. I think the high would be determined by the tweeter more than the mid. I want the low to be at around 350. The Morel MW144 looks like it can handle down that low without any problems.

Driver : Morel MW144 5" Woofer
Project by : Mark Rice
Project for : you
--
Number of drivers : 3
Box type : Closed
Box size : 36.8 l


Relative
Freq Gain SPL
[Hz] [dB] [dB]
Driver : Morel MW144 5" Woofer
Project by : Mark Rice
Project for : you
--
Number of drivers : 3
Box type : Closed
Box size : 36.8 l


Relative
Freq Gain SPL
[Hz] [dB] [dB]
350.00 0.00 92.77
360.00 0.00 92.77
370.00 0.00 92.77
380.00 0.00 92.77
390.00 0.00 92.77
400.00 0.00 92.77


3380.00 0.00 92.77
3390.00 0.00 92.77
3400.00 0.00 92.77
3410.00 0.00 92.77
3420.00 0.00 92.77
3430.00 0.00 92.77
3440.00 0.00 92.77
3450.00 0.00 92.77
3460.00 0.00 92.77
3470.00 0.00 92.77
3480.00 0.00 92.77
3490.00 0.00 92.77
3500.00 0.00 92.77

Before I get any further I should point out that I am using the freeware version of WinISD for these predictions. I also am working on getting some test equipment set up but I have no way of testing drivers at this point. (I am noob, sorry)

Woofers:
I am looking at two possibilities.

1. The Dayton RS225-8 will get down to 27Hz with 3 of them. The box specs I got with WinISD show a vented box 193.7 liters with a vent 4” diameter X 2.44 long, shows mach .12. This is tuned to 28.75 Hz. I would place the vent towards the bottom on the front unless there is a better place to put it. I am not worried about looks so much as I am performance.

Spl level for 3 drivers:
Driver : Dayton RS225S-8 Woofer
Project by : Mark Rice
Project for : you
--
Number of drivers : 3
Box type : Vented
Box size : 193.7 l
Tuning frequency : 28.75 Hz
Vent : 1 vent(s)
2.99 in length for each
4.02 in round


Relative
Freq Gain SPL
[Hz] [dB] [dB]
28.00 -3.24 89.53
29.00 -2.56 90.21
30.00 -1.99 90.79
31.00 -1.51 91.26
32.00 -1.13 91.64
33.00 -0.82 91.95
34.00 -0.58 92.19
35.00 -0.39 92.38
36.00 -0.25 92.52
37.00 -0.14 92.63
38.00 -0.06 92.71
39.00 0.00 92.77


40.00 0.04 92.81
45.00 0.12 92.89
50.00 0.10 92.87
55.00 0.07 92.85
60.00 0.05 92.82
65.00 0.03 92.80
70.00 0.01 92.79
75.00 0.00 92.78
80.00 0.00 92.77
85.00 -0.01 92.76
90.00 -0.01 92.76
95.00 -0.01 92.76
100.00 -0.01 92.76
105.00 -0.01 92.76
110.00 -0.01 92.76
115.00 -0.01 92.76
120.00 -0.01 92.76
125.00 -0.01 92.76
130.00 -0.01 92.76
135.00 -0.01 92.76
140.00 -0.01 92.76
145.00 -0.01 92.76
150.00 -0.01 92.76
155.00 -0.01 92.76
160.00 -0.01 92.76
165.00 -0.01 92.76
170.00 -0.01 92.76
175.00 -0.01 92.76
180.00 -0.01 92.76
185.00 -0.01 92.76
190.00 -0.01 92.76
195.00 -0.01 92.76
200.00 -0.01 92.76
205.00 -0.01 92.76
210.00 -0.01 92.76
215.00 -0.01 92.76
220.00 -0.01 92.76
225.00 -0.01 92.76
230.00 -0.01 92.76
235.00 -0.01 92.76
240.00 -0.01 92.77
245.00 -0.01 92.77
250.00 -0.01 92.77
255.00 -0.01 92.77
260.00 -0.01 92.77
265.00 -0.01 92.77
270.00 0.00 92.77
275.00 0.00 92.77
280.00 0.00 92.77
285.00 0.00 92.77
290.00 0.00 92.77
295.00 0.00 92.77
300.00 0.00 92.77
305.00 0.00 92.77
310.00 0.00 92.77
315.00 0.00 92.77
320.00 0.00 92.77
325.00 0.00 92.77
330.00 0.00 92.77
335.00 0.00 92.77
340.00 0.00 92.77
345.00 0.00 92.77
350.00 0.00 92.77


Specifications:
Power handling: 80 watts RMS/120 watts max
VCdia: 1.5"
Le: 1.0 mH
Znom: 8 ohms
Re: 6.4 ohms
Frequency range: 27-2,000 Hz
Fs: 27 Hz
SPL: 88.1 dB 2.83V/1m
Vas: 2.75 cu. ft.
Qms: 1.60
Qes: .47
Qts: .37
Xmax: 7 mm
Dimensions: A: 8-3/4", B: 7-3/8", C: 4".

2. Two Seas CA22RNX woofers will also get down to 27Hz with only two of them. WinSD calls for a vented 8.07 cu ft. This is just a little smaller than the other speakers. This one has a vent 4 inches wide and 2.2 long. This box is tuned to 28.4 Hz..

Outside diameter 221.4mm
Cut out 186.4mm
Depth 90mm
25.4mm = 1" = 2.54cm

Nominal Impedance 8 Ohms
Recom. frequency range 30-3000 Hz
Short term max. power 250 W
Long term max. power 80 W
Sensitivity (1W/1m) 89.5 dB

Voice Coil Diameter 39 mm
Voice coil height 18 mm
Air gap height 6 mm
Linear coil travel (p-p) 12 mm
Max. coil travel (p-p) 26 mm
Magnet weight 0.64 Kg
Total weight 2.2 Kg
Voice coil resistance 6.1 Ohms
Voice coil inductance 1.0 mH
Force factor 7.0 N/A
Free air resonance 29 Hz
Moving mass 20.9 g
Suspension compliance 1.4 mm/N
Suspension mech. resistance 2.05 Ns/m
Effective piston area 230 sq. cm
Vas 97 Liters
Qms 2.04
Qes 0.52
Suggested Box Alignments:
Sealed box of 50 liters (1.8cf); f3 of 49Hz
Vented box of 70 liters (2.5cf); 3" diameter vent by 6.5" long; f3 of 31Hz

Number of drivers : 2
Box type : Vented
Box size : 7.227 ft^3
Tuning frequency : 28.52 Hz
Vent : 1 vent(s)
0.070 m length for each
4.02 in round


Relative
Freq Gain SPL
[Hz] [dB] [dB]
20.00 -12.44 80.07
21.00 -10.79 81.72
22.00 -9.26 83.25
23.00 -7.85 84.66
24.00 -6.57 85.94
25.00 -5.43 87.08
26.00 -4.43 88.08
27.00 -3.56 88.95
28.00 -2.83 89.68
29.00 -2.23 90.28
30.00 -1.75 90.76
31.00 -1.36 91.15
32.00 -1.05 91.46
33.00 -0.82 91.69
34.00 -0.64 91.87
35.00 -0.50 92.01
36.00 -0.39 92.12
37.00 -0.31 92.20
38.00 -0.25 92.26
39.00 -0.21 92.30
40.00 -0.17 92.34
83.00 -0.05 92.46
84.00 -0.05 92.46
85.00 -0.05 92.46
86.00 -0.05 92.46
87.00 -0.05 92.46
88.00 -0.05 92.46
89.00 -0.05 92.46
90.00 -0.05 92.46
91.00 -0.05 92.46
92.00 -0.04 92.47
93.00 -0.04 92.47
94.00 -0.04 92.47
95.00 -0.04 92.47
96.00 -0.04 92.47
97.00 -0.04 92.47
98.00 -0.04 92.47
99.00 -0.04 92.47
100.00 -0.04 92.47

Either way, it looks like there would not need to be any attenuation for the SPL levels. I also want to use L-Pads in the crossovers unless there is a reason not to.

With all considered I am at an impasse as to which driver to use for the mid bass. :E I need to work on the enclosures some more I think. If anyone sees any flaws that I didn’t please tell me. I try to do as much on paper as I can before I start ordering stuff. That saves me from explaining to the wife how come I have all this extra stuff sitting around. If this whole thing is a bad idea I really would like to know. Thanks for any advice that I can get guys.

[NoNoBadDog]

Some samples of the case drawings:

[---k---]

If you've never designed a speaker before, yes you are in over your head. way over. just look at some of JonMarsh's build threads or the other ones recently to see what all goes into the designs. Of course, around here we do things to get the best design. You can cut corners and design by ear, but the results aren't as good.

First, I think your goals are way too high. You don't need that much power handling and spl. If you do insist on keeping those goals, you're going to need to be looking at pro sound drivers and tweaters w/ waveguide or horns. There was a similar thread a while ago where someone had the same lofty goals, and the discussion was about pro sound drivers. I'll look for it later.

Finally, I would consider my Khanspires. http://htguide.com/forum/showthread.php4?t=26309

I only say this because I need an ego boost.
Actually, they are amazing speakers, fit within your size limits, should be able to met your volume requirements, don't have any padding, and can be easily built ported if you want more low end.

[ThomasW]

Yes you're in over your head...

Due to comb-filtering problems you don't want 3 midranges operating to 3.5kHz...

Since you're in Aurora, you might want to drop by my place (off intersection of I-25 and Hampden), to hear the NeoD cc mated to bass bins. We can chat about different things to build.

PM if you're interested

Regards
Thomas

[PoorboyMike]

Yes you're in over your head...

Due to comb-filtering problems you don't want 3 midranges operating to 3.5kHz...

Since you're in Aurora, you might want to drop by my place (off intersection of I-25 and Hampden), to hear the NeoD cc mated to bass bins. We can chat about different things to build.

PM if you're interested

Regards
Thomas

Hi Thomas,

What are you using for bass bins and how do you have them crossed over the NeoD cc?

I'm still considering something like this for my basement theater in our new house. I'll probably use NatPs though, since I already have 2 of them. 3 NatPs all on bass bins behind an AT screen. Yeah, that's the ticket. :B

The excavator just finished digging the basement so we are finally under way. :T Getting a little off topic/hyjacking here. Sorry.

[ThomasW]

Unfortunately Comcast has hosed everyone's webpages so I can't post any pictures.

Right now I'm using a little 18" cube containing a 12" TC2+. That will change to a purpose built bin containing a pair of the new PE high excursion 8" or maybe the RS265.

The bin will be a little different than most in that at the top of the cabinet there will be ~6"-8" of empty space between the woofers in the bin and NeoD cc box above it.

Crossover will be a Behringer CX3400

[NoNoBadDog]

Sounds like pursuing this idea will be a waste of time. That is more time that I didn't waste.

I have been looking at the NeoD cc design and they look like they will be a good match for the Dayton TMWWs. That means I need to finish up the new cabinets for the Daytons and get atarted on cabinets for the NeoDs.

Thanks Folks, for the input!