Quick question: which ohm value to use in xover (1 Viewer)

[Mark_E_Smith]

These stryke drivers are not looking very good so far, in a ported box they have 2 -3db dips in the 300 Hz to 450 Hz and 700 Hz to 1KHz and a 4 db hump from 100 Hz to 250 Hz so thats a 7 db spread in the critical human voice range the morel looks real sweet though. also the off axis on the strykes gets kinda bad after 1kHz this means a more focused listening point and less openess. Why did you choose these drivers?

 

[Mark_E_Smith]

How do I post a picture or a bit map, I have a response graph that I would like to post?

 

[Chris Carswell]

Dang Mark, You da man!!!! I'm glad I got you on my side
Now to answer some of your questions:
Sealed:
The top parts are sealed off from the sub. I thought it might help as well since it wouldn't play as low(Great minds think alike ). As you can sort of see dun to my crappy pic it is braced twice but the bottom brace seals it off from the SVS sub part which is what's vented. Now the pic of the surround tower shows it braced as well but the bottom brace is still opened b/c it will be ported. That way it could go lower and be used as a main pair of speakers if need be.
2.5 WAY
The general idea behind using a 2.5-way design is to use a tweeter, and 2 midwoofers. I went with a MTM design, where the tweeter is situated between the 2 midwoofers. In a 2.5 way, the upper midwoofer is used for handling the bass/midrange running all the way through its frequency response up to the crossover frequency with the tweeter. The lower midwoofer is used to extend the bass lower and defeat the baffle step loss that occurs when bass from a speaker radiates all around. It runs between its low end response to somewhere around 500Hz (or what ever Hz you choose to cross it over at), which is usually where the baffle step loss starts to dissipate as the rest of the frequency spectrum becomes more directional and radiates in front of its baffle (front panel). Thus this design is called a 2.5-way design (adapted from Pat's Page).
In my case think of the SVS sub as the lower unit running, say 150hz down and the 2 SA071 mid woofers as the upper ones allowed to run all the way through its frequency response up to the xover point selected for it. This is opposed to making a messy & complicated (to me) 3 way xover for the towers and then making 3, 2way crossovers for the center and the L & R surround. This way I can just make 5 xovers all the same but then play with some simple low pass in-line filters for the subs until I get it where I want it.
QTs for SVS:
A QTs of 3? No Way. More like .3 The Qts for the SVS sub is correct. They were posted here by MR. SVS Tech Guy himself then I reposted them week ago.
Drivers:
I want to get these drivers b/c the spec's look pretty good & seamed like something to work with, they look cool(not to best reason I know), and the main factor is they on sale for $10 each!!! I guess it is becoming apparent they might sound like they are $10 :frowning: Darn. I try to be optimistic. I didn't think they were that bad. Off axis 45 degrees yah, they don't look so hot. I would like to use them but if you think they are REALLY, REALLY that bad in those areas & I shouldn't order them LMK. The only other driver in ~ about that price range would be the 6 1/2" Dayton 295-305 from PE. It is $15, which I can handle. I have seen a few projects with it. Here are the specs on it if you feel like playing with the two to see which is better:
Power handling: 50 watts RMS/75 watts max *
Voice coil diameter: 1-3/8" *
Voice coil inductance: 1.40 mH *
Impedance: 8 ohms *
DC resistance: 6.0 ohms *
Frequency response: 33-4,000 Hz *
Fs: 33 Hz *
SPL: 88 dB 1W/1m *
Vas: .98 cu. ft. *
Qms: 2.75 *
Qes: .37 *
Qts: .33 *
Xmax: 3.15mm *
Here is a LINK to its CLIO Frequency Response.
How to post a Pic:
When you reply to this great thread look in the tool box area next to where it says SIZE v FONT v COLOR v. You will see an IMG tab. Click on it. Now put the web address where it can be seen. If you don't have it loaded to the web on your own site or somewhere else, email it to me & I will put it up on mine for all to see.
Thanks again Mark for all that you have done. I am TRULY grateful. :star: :star: :star: :star: :star:
-Chris

 

[Mark_E_Smith]

Brain fade on the Qts I ment Qms. The 2.5 is an interesting concept, however it would require another x-over and it would reduce the overall SPL.
I was going to recomend that driver also if you are going to use it you might consider the Dayton 3s they are supposed to sound really good and they are a MTM design.
http://www.partsexpress.com/resource...ayton_iii.html
You could still use the basic tower design just build these into it
The best thing is the designer has a killer x-over that has been perfected. This guy has forgoten more than I know now

I will e-mail the graph.

 

[Chris Carswell]

Mark, I can't thank you enough for doing these for me.
Here are the graphs Mark provided:
Stryke SA071 & Morel MDT-20

Dayton 295-305 & Morel MDT-20

Well, what do ya'all think

 

[Patrick Sun]

The Stryke/Morel combo will probably need some padding once the baffle step kicks in under normal placement in the room.

The Dayton/Morel combo is crossed too low using just a single cap on the tweeter.

 

[Chris Carswell]

Mark, I have a few questions for ya after looking at the graphs more.

1.What are the crossover Hz for both combos, Stryke/Morel & Dayton/Morel?
2.What are the C1,C2,L1,L2 values for the Stryke/Morel?
3.Why do we have the Stryke's wired in series? Would it have an additional +3dB boost in the freq. response if wired in parallel?

Pat, What do you suggest?

 

[Mark_E_Smith]

Sent some updates for both and learned how to paste more info out of the software.

1 See new info

2 ditto

3 They were overpowering the tweeter. (woofers to loud) if you look at the graph from Stryke have a sensitivity more like 90 to 92 spl 1w/1m per speaker I will graph and send that.

 

[Chris Carswell]

Mark sent me some new Graphs and changes. Tell us what you think.
Stryke Morel Adjusted:
I added the lines to see + - 3dB.

Dayton Morel Adjusted:
Again, I added the lines to show + - 3dB.

This last graph & schm. is off the Parts express web page for the MTM Project Dayton. Use it to compare.
PE Dayton Project:

Thanks again Mark!!!
Lets keep the ideas comments comming

 

[Chris Carswell]

You know, looking at the Dayton Morel Adjusted graph compared to the original one, the original looks a little better. It only has a + - 3dB swing where the new one has a + - 5dB swing.
Yes/No??????

 

[Patrick Sun]

No, the Dayton/Morel's center SPL line should be drawn around -3dB. I'd do the Dayton Morel combo if it were me.

 

[Mark_E_Smith]

I would also and I might just do it as it looks real sweet in the midrange and it has a lower end hump to help with the infamous baffle step. the only problem is they will not blow your hair back with spl maybe maxout around 108 db but thats preety loud for most people me included

 

[Chris Carswell]

OK, so we have the center line at -3dB, which already is the orange line for reference. It rises to a peak of -1dB at 180Hz then falls to -6dB at 1750Hz. Is that not a 5dB swing like I stated or am I reading it wrong? I do see what you are saying and how to read it the correct way. I just had a different way of thinking about it. At the center -3dB line, at any given point it would be no more that + - 3dB away from it. The way I made it sound was worse. :b

 

[Mark_E_Smith]

If you look at the curve above 500 Hz it is fairly smooth, below 500 Hz you see a rise of about 6db this is a good thing as this will compensate for baffle step which is generaly a -6 db slope below 500 Hz. But these are predictions and not the real thing. The only way to get it perfect is to build them and test them and tweek them. But I maintain even with this crossover they will be better than most speakers you could buy for 4 X the money

 

[Chris Carswell]

COOL!!! So Marks latest xover seems to be OK. Hats off to you Mark again, YOU DA MAN

 

[Chris Carswell]

Here are the specs of another 2 divers I am considering. The GR-165 and GR-M16, both from GR Research. If anyone wants to model these. Thanks!!!
GR 165
FS 39.5 Hz
RE 10.85 ohms
Qms 2.52
Qts .53
Qes .67
Xmax 4.5mm
L (1k) .34 mH
L (10k) .62 mH
Vas 36.26 Liters
Ms 11.91 grams
Cms 1.374 mm/newt
Bl 6.89 Tesla-M
SPL 87.5 db
Area 137.07 sq cm

----------------------------------------------------------
GR M16
FS 40 Hz
RE 5.55 ohms
Qms 2.2
Qts .39
Qes .47
Xmax 3.5mm
L (1k) .86 mH
L (10k) .38 mH
Vas 29 Liters
Ms 12.29 grams
Cms 1.913 mm/newt
Bl 7.97 Tesla-M
SPL 88.5 db
Area 137.07 sq cm

*The M16 looks to be smoother, but it is not to be able to go as low (Hz) as the 165 so I have been told*