SB Acoustics MTM build X-Over help

[bassman_soundking]

Im building a pair or MTMs
Drivers: Sb Acoustics Sb15NRXC30-8, and SB29RDAC-C0004

I have a crossover design and would like some opinions on it

The plan is to use Knock downs from PE
I have the 1.16ft3 versions, External dimensions: 34" H x 8" W x 11" D
Probably going to partition the internal volume to somewhere between .5FT3 and .7 ft3

Im uploading a PDF with a potential X-Over design and PDFs of the drivers

If there are issues or you have a different design please chime in!

[bassman_soundking]

[bassman_soundking]

[fpitas]

I don't see your crossover. Edit: now I do!

[a4eaudio]

I see the schematic fine.

[bassman_soundking]

Its not showing for you?
It right above your post in schematic form.below it is the expected frequency response plot.

Its also in the original post as a download (leap)​

[fpitas]

Its not showing for you?
It right above your post in schematic form.below it is the expected frequency response plot.

Its also in the original post as a download (leap)​

Nothing showing to me. I saw the LEAP, but people will need the actual schematic and the full measured driver data in your box to analyze your crossover accurately. Might help if the LEAP graph showed phase for both drivers, too.

[PWR RYD]

I think those drivers should work very well together. That knock down enclosure should be just about the perfect internal net volume for two of those SB15NRXC30-8 midbasses wired in parallel. I would estimate a 2.5" diameter port tuned to the low 40's should yield some very nice bass. I can't speak for that crossover as I didn't take the inbox measurements or design it. It might be quite good, or it might suck No idea who Tom Roberts is and I have never heard one of his designs.

[bassman_soundking]

Im not sure why its not showing up.
I have specs from both drivers as well listed.

I attached as PDF in original post, and also from POSTIMAGE site as well

Ill tryt to do something else in after I take my granddaughter top get a slurpee

[Chris Roemer]

I see everything (7 y.o. design from madison?).

Could be okay ...
I've found ms filter designs to not have much baffle-step?
This looks a bit more like a "smiley-face" than straight BSC (but, you might like it).
If you found the tweeter too bright you can always up the series resistor by 2-3 ohms.

I'd favor the larger end of your box range. Tuned in the low 40s should reach into the low 50s.
2-1/2" would be about 8" long.
A 2" "Precision Port" needs only be 5" long. Prob'ly be OK (aiming the vent out the rear can help mask any chuffing problems, if you can do it).

[bassman_soundking]

I think those drivers should work very well together. That knock down enclosure should be just about the perfect internal net volume for two of those SB15NRXC30-8 midbasses wired in parallel. I would estimate a 2.5" diameter port tuned to the low 40's should yield some very nice bass. I can't speak for that crossover as I didn't take the inbox measurements or design it. It might be quite good, or it might suck No idea who Tom Roberts is and I have never heard one of his designs.

Thats the thing.
The design came from Madisound.
I guess they ran the numbers, but not sure for what enclosure.
Seems like my data I added here is just showing up on my end for some reason, but the resp[onse seems to emphasize the bass more that the midrange and highs, maybe thats good?
I have no idea, but josh at Madisound gave me this after I asked him about these drivers.

Id gladly trade quality midbass for low bass extension if its an either/or based on x-over and box volume.
My closet is FULL or raw sub drivers to use for the low end if needed.

Can you recommend a way to upload my dats here so that others can see it?


So Ill need a microphone to measure in box response to make the x-over properly?

[bassman_soundking]

I see everything (7 y.o. design from madison?).

Could be okay ...
I've found ms filter designs to not have much baffle-step?
This looks a bit more like a "smiley-face" than straight BSC (but, you might like it).
If you found the tweeter too bright you can always up the series resistor by 2-3 ohms.

I'd favor the larger end of your box range. Tuned in the low 40s should reach into the low 50s.
2-1/2" would be about 8" long.
A 2" "Precision Port" needs only be 5" long. Prob'ly be OK (aiming the vent out the rear can help mask any chuffing problems, if you can do it).

A 2.5" x 8" long port is easily doable.
I was just worried about losing mid-bass quality with a larger enclosure.

I already have fun speakers.
​​​​​​These days I'm looking for high fidelity and accuracy..
I've found most of my speakers and my current tastes don't necessarily align as well anymore.

[rpb]

A 2.5" x 8" long port is easily doable.
I was just worried about losing mid-bass quality with a larger enclosure.

I already have fun speakers.
​​​​​​These days I'm looking for high fidelity and accuracy..
I've found most of my speakers and my current tastes don't necessarily align as well anymore.

If you can measure the response of your old speakers, it will show the differences between them, and may help pinpoint the response you prefer. A small change in frequency response can make, or break the sound quality.

[bassman_soundking]

If you can measure the response of your old speakers, it will show the differences between them, and may help pinpoint the response you prefer. A small change in frequency response can make, or break the sound quality.

I have decided to buy a measurement mic.
Im just debating availability price and performance.
Seriously on a budget, but dont want to waste money on xo parts either.
Any recommendation?

[rpb]

I have decided to buy a measurement mic.
Im just debating availability price and performance.
Seriously on a budget, but dont want to waste money on xo parts either.
Any recommendation?

There's plenty of options, and I think a lot depends on how you want to do things. I use an EMM-6, or something similar to it, and a 2-ch mixer. I use HOLM software. It's free.

One option is to see if there is anyone in your area that can measure for you. With most choices, there is a bit of a learning curve.

[bassman_soundking]

There's plenty of options, and I think a lot depends on how you want to do things. I use an EMM-6, or something similar to it, and a 2-ch mixer. I use HOLM software. It's free.

One option is to see if there is anyone in your area that can measure for you. With most choices, there is a bit of a learning curve.

I have a tiny cluttered place (too small) thats not optimal for measuring let alone high end speakers.
Yert here I am lol.

Most of my local friends are just buy Best Buy speakers kind or use Portable BT speakers, The rest are Car audio Bassheads. So no one I can think of with a proper mic pr skill to take measurements.

Is there any reason to spens $20 more on the miniDSP UMIK1

[a4eaudio]

There are some advantages to dual channel microphones (like EMM-6) but you then need a preamp also, which could be a Behringer or some other brand not too expensive.
USB mics like UMM-6 or UMIK are super easy but can't take into account some of the phase/timing so you have to manually process the data. So they are a little more expensive than the EMM-6 but if you get the EMM-6 you'll need a preamp and total cost is more. I don't think the UMIK1 is necessarily worth the $20 but one thing that is nice to feel comfortable is to get a calibrated mic from Cross Spectrum labs, as the manufacture calibration are sometimes a little suspect. (For complete disclosure, I have UMIK1 calibrated by cross spectrum labs that I don't use now as I have an EMM-6 bought used and calibrated by a forum member and use with a Steinberg MarkII preamp bought used on ebay). One thing to consider too is that if you get a pretty good mic you can probably sell it for more than 50% if you decide you will never use it again. If you get something on the cheap side, the resale value suffers.