DIY PSA MTM-212-M

Tagged: MTM-212, MTM-212-M, power sound audio, PSA

This topic has 33 replies, 4 voices, and was last updated 9 months, 1 week ago by Chedwin.

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- raj
 
 February 15, 2025 at 4:29 pm #56793
 
 Hello All,
 
 I have done hours of research r and d and could use your help with wiring and building the highest quality crossover,
 
 I have the drivers from these sperakers and the enclosure designs I need help with crossover and dialling these in
 
 I’m building and LCR and I would like to document it and list all of the parts and plans I don’t care about making money off it I just want to put it out there for the diy community and make it myself as an LCR Setup here is what I have
 
 -B&C 464 Co-ax mid and tweeter:https://www.bcspeakers.com/en/products/coaxials-hf/1-4/16/DCX464-16
 -Cast aluminum exponential horn:https://www.bcspeakers.com/en/products/horn/1-4/0/me90
 -Dual 12″ neodymium high efficiency Italian woofers:https://www.bcspeakers.com/en/products/lf-driver/12-0/8/12ndl76
 
 -Frequency Response = 60Hz – 18kHz
 
 I need help to create the crossover I have the microphone for testing I will need support building the crossover anyone have any ideas ?
 
 Kind regards
 
 Rajan ark
 
 +447530353414 WhatsApp
- Chedwin
 
 February 15, 2025 at 5:52 pm #56794
 
 Very happy to see the DCX424 getting recognition and use in HT and DIY speaker builds. It has very quickly become my favourite sounding driver choice for natural sounding vocal reproduction in a pro audio speaker range using it ive started working with alot
 
 Others on the forum may be able to assist quicker than me due to my irregular work schedule (live sound engineer in pro audio) but Ill be happy to take a look at this for you if no one else has before I get the time
 - raj
 
 February 15, 2025 at 7:55 pm #56796
 
 thanks man I can pay you for your time and effort that goes into it
- raj
 
 February 16, 2025 at 9:45 am #56803
 
 @Toids_DIY_Audio is this something you can assist with ?
- TVOR-Ceasar
 
 February 16, 2025 at 9:20 pm #56806
 
 I can get the full set of graphs from Parts Express and use FPGraphTracer to get the FRD and MA files.
 
 Do you have a schematic of the crossover?
- raj
 
 February 16, 2025 at 10:04 pm #56807
 
 hey man i dont have Do you have a schematic of the crossover,
 
 Im new to crossover designs hence why I need to find a person that I can pay that will design everything for me similar to the psa crossover in the picture.
 - Big_Al
 
 February 16, 2025 at 11:46 pm #56808
 
 Hey Raj, if I’m understanding you correctly, you’re looking to implement two 12NDL76 subwoofers and one DCX464 in each speaker, correct?
 
 Additional questions:
 1. What amplifier are you intending to use? (or what level of Ohms is okay & how much wattage)
 
 2. You said you wanted the range to be 60-18khz. Where do you want the subwoofers to end and the tweeter/horn to start?
 
 3. You may be able to save yourself some trouble with pre-assembled crossovers. https://www.parts-express.com/speaker-components/crossover-components/assembled-passive-crossovers
 - Big_Al
 
 February 16, 2025 at 11:49 pm #56809
 
 edit —ignore—
 
 This reply was modified 9 months, 2 weeks ago by Big_Al.
 - Chedwin
 
 February 17, 2025 at 12:11 am #56810
 
 The prebuilt B&C xover linked is for the ME464 polyurethane horn which loads the coax driver down to about 300hz
 
 Raj is using the ME90 aluminium horn which only loads the driver down to around 900hz
 - Big_Al
 
 February 17, 2025 at 12:18 am #56812
 
 Good catch. Thanks
 - Chedwin
 
 February 17, 2025 at 12:17 am #56811
 
 The DCX464 behaves unlike any other driver ive ever come across in the mid range as its a coaxial compression driver, not compression hi with woofer mid.
 
 When xover designed correctly the phase alignment and transient resposne of the entire frequency range 500hz-15khz is so closely matched between the 2 compression drivers the vocal reproduction is insanely natural sounding. xover may need more detail and care than a usual compression to woofer hi mid xover slopes
 
 I wouldn’t be comfortable suggesting a non B&C prebuilt crossover be used with this driver between the hi and mid diaphragms
 
 This reply was modified 9 months, 2 weeks ago by Chedwin. Reason: typo
- raj
 
 February 17, 2025 at 12:18 am #56813
 
 Hello All,
 
 The FB464 will work for the horn ME464 which goes down to 300hz,
 
 I would like this at 4 ohms and power wise as high as you can get tbh 600 or 700 rms high sensitivity
 
 in this region would be good
 
 -Sensitivity = 100dB 1W/1M
 -Nominal Impedance = 4 Ohms
 -Power Handling = 500 W
 - Big_Al
 
 February 17, 2025 at 12:22 am #56815
 
 The DCX464 only goes down to 8 Ohm, unless you are wanting to use two (or more) of them.
 - raj
 
 February 17, 2025 at 12:25 am #56817
 
 yea but wiring in parallel with the 2 mid range woofers would that not work ?
 - Big_Al
 
 February 17, 2025 at 12:33 am #56818
 
 You need the two types of driver on their own circuits so that the Hz can be assigned with the crossover.
 
 Example:
 
 * Power —- Crossover >300hz —– tweeter
 
 * Power —–Crossover <300hz —–sub
 - Chedwin
 
 February 17, 2025 at 12:36 am #56822
 
 If you use the 4ohm 12″ woofers you can get a final speaker impedance of 4ohms
 
 2x 12″ 4ohm in series is 8ohms on the lows
 
 16ohm dcx464 with diaphragms wired in parellel gives 8ohms on the hi & mid combined
 
 parallel the low driver seires with the dcx464 parallel for final 4ohm
 - Big_Al
 
 February 17, 2025 at 12:37 am #56823
 
 I think the problem is that I don’t understand this horn. Is it one driver or two? How many voice coils are we working with here?
 - Chedwin
 
 February 17, 2025 at 12:44 am #56826
 
 the DCX464 is dual concentric compression driver ring diaphragms sharing a housing
 
 The inner ring does >3.5khz (ish)
 
 the outer ring doesn <3.5khz (ish)
 
 the output from both compression rings combine within the housing and share a single exit to be loaded by the horn as a single cohesive output covering a very wide frequency range. It is a radical change in design philosophy from standard compression driver over mid woofer concepts
 
 once you have the xover between the 2 compression rings for the horn being used sorted out you would consider the dcx464 as a single unit and work out the xover point between it and your low woofers like you would with a standard woofer with single compression driver speaker design
 - Big_Al
 
 February 17, 2025 at 12:47 am #56827
 
 Thank you. I understand now. So in parallel you should have 4 Ohm, right?
 - Chedwin
 
 February 17, 2025 at 12:48 am #56828
 
 depends which model you use, the dcx464 comes in 8 and 16 ohm versions
 - Big_Al
 
 February 17, 2025 at 12:49 am #56829
 
 True. Presuming you used 8 Ohm model.
 - Chedwin
 
 February 17, 2025 at 12:50 am #56830
 
 yes 8ohm model with diaphrams in parallel is 4ohm load
 - raj
 
 February 17, 2025 at 12:38 am #56824
 
 thanks for working that out as I would have no idea
 
 im working on trying to get the cut sheets for the boxes and i got stuck on the crossover etc thanks for everyone’s help this will sound beast
- raj
 
 February 17, 2025 at 12:34 am #56819
 
 this is what I have come up with
 
 Breakdown of the Crossover Design:
 1. Mid-Woofer Crossover (Top Board)
 
 <ul data-start=”374″ data-end=”679″>
 2. The 82 µF capacitor suggests a low-pass filter around 320 Hz, likely filtering out frequencies above that for the mid-woofers.
 3. The 22 µF and 11 µF capacitors suggest a high-pass crossover at 1073 Hz and 1697 Hz, which would cut off lower frequencies going to the compression driver.
 4. Compression Driver Crossover (Bottom Board)
 
 <ul data-start=”737″ data-end=”1045″>
 5. Since compression drivers typically work in the high-frequency range, the 22 µF + 11 µF combination creates a high-pass filter around 1.7 kHz.
 6. This means the compression driver is likely handling frequencies above ~1.7 kHz, while the mid-woofers cover the range from 320 Hz to 1.7 kHz.
 Summary of Crossover Points:
 
 <ul data-start=”1080″ data-end=”1217″>
- Woofer Low-Pass: ~320 Hz
- Midrange Band-Pass: ~320 Hz to ~1.7 kHz
- Compression Driver High-Pass: ~1.7 kHz and above