I'm building a lightweight, portable variant of Scott Hinson's 'MEH' design that he shared on his DIYRM page on Facebook (https://www.facebook.com/DIYRM). The PDF is here: https://drive.google.com/file/d/1nE...lkT3rECpb8WYPMgiS_8pSvRAGxZkbaGmzzkCrsYXF9w8o
Looking to swap the B&C 10nw76 drivers for 10cl51 (saving nearly 2kg per driver) and the DCX354 in place of the DCX454 he uses, saving another 2kg... a total of 6kg saving!
I used his parameters in Hornresp, but with he 10cl51 specs, and got a plot with similar or better SPL from 55Hz upwards. See image below. Left hand side is the plot from Scott's instructions with the 10w76. Right hand side is my plot with the 10cl51 specs.
I know the 10nw76 has more power handling, but I'm limited to 150watts, which is the max my battery powered TPA3255 amps will supply per speaker. I'm happy to pair with a sub and/or use a bit of DSP to fill in the bottom end (with boost, or psychoacoustics)
Am I missing anything? Any issue crossing to the DCX354 at 400hz, instead of the 300Hz possible with the larger DCX454.
Thanks!
(PS: I know this is heading in the direction of the SynTripP design, but I found Scott's instructions more complete and the rear ports seem to me to be easier to 'play' with as I'm experimenting with different drivers and tuning)
Looking to swap the B&C 10nw76 drivers for 10cl51 (saving nearly 2kg per driver) and the DCX354 in place of the DCX454 he uses, saving another 2kg... a total of 6kg saving!
I used his parameters in Hornresp, but with he 10cl51 specs, and got a plot with similar or better SPL from 55Hz upwards. See image below. Left hand side is the plot from Scott's instructions with the 10w76. Right hand side is my plot with the 10cl51 specs.
I know the 10nw76 has more power handling, but I'm limited to 150watts, which is the max my battery powered TPA3255 amps will supply per speaker. I'm happy to pair with a sub and/or use a bit of DSP to fill in the bottom end (with boost, or psychoacoustics)
Am I missing anything? Any issue crossing to the DCX354 at 400hz, instead of the 300Hz possible with the larger DCX454.
Thanks!
(PS: I know this is heading in the direction of the SynTripP design, but I found Scott's instructions more complete and the rear ports seem to me to be easier to 'play' with as I'm experimenting with different drivers and tuning)
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I’m delighted with the build… after some discussion on Facebook I opted for the DCX464 as it is rated down to 300hz whereas the DCX354 is only 400hz which would have put the crossover a little too high for the center to center spacing of the woofer ports in the horn. I used 10cl51 for the woofers as I already had one on hand and wanted a light build… it saved about 5kg but the low end rolls of f quite early… starting around 150hz leaving a small gap before my Tham 12 sub comes in abound 110hz… but once EQd and time aligned the setup is sublime. I made it as a portable battery powered setup that we mainly play outdoors and everyone who hears it is blown away. Everything is powerful, effortless… we like our thumping dance music which sounds great, but when some beautiful strings or vocal comes through it really is something to behold. When people who heard the setup hear a song they like on another system they’ll invariably say: oooh, I’d love to hear this on your speaker! It’s now both my party rig and office setup and I love it. Will probably order some 4ohm versions of the 10NW76 that Scott originally specced to replace the lightweight drivers I substituted. He really nailed it with this design and I could not recommend it highly enough. Freq and phase plot from my latest tune attached… indoor measurements as it’s too rainy to do it outside right now (I will try some FIR filters to get that last bit of perfection out of it but not sure how much it will add) plus a photo from our last party in the woods… note the design is intended for horizontal orientation to achieve wider dispersion but because there’s only a few of us in the woods we tend to have it vertically.
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Great to see that! I also struggle with picking DCX354 or DCX464 and also go for DCX464 like you.
Did you use the FB464 crossover from B&C in your setup? And is that MOTU M4 on the top for 4ch output to drive this?
I'm now building the cabinet and I'm planning to use M4 as source with FB464 XO since I only have 4ch source/amp.
The woofer Scott picked is 8ohm 10NW76 by the way.
Did you use the FB464 crossover from B&C in your setup? And is that MOTU M4 on the top for 4ch output to drive this?
I'm now building the cabinet and I'm planning to use M4 as source with FB464 XO since I only have 4ch source/amp.
The woofer Scott picked is 8ohm 10NW76 by the way.
Yep, on axis - the roll off is just the house curve I used, there’s lots of top end if that’s what you’re after.
I like how you flipped it sideways. I've wondered which conditions make it better to trade ceiling for side when it isn't an axisymmetric design.
Mine is fully active. The motu m4 gives me 4 channels of output - 2 for the dcx 464, one for the 10 inch drivers and 1 for the sub. I run a mono system. Each of the 6 drivers have their own tpa3255 amp channel. You could certainly use the m4 plus the b&c crossover for a 4 chan stereo system without sub, but because I’m running of battery and therefore voltage limited I’m after the maximum amount of sensitivity and amps to maximize wattage / output.. The m4 works great with a raspberry pi and Camilla DSP by the way!
I think it looks better that way, and there are not a lot of reflections to worry about outdoors! In my office I’m so close that the first reflections likely land behind me! It also works well outdoors because we stand (dance, jump, gawp in amazement at the sound) quite close 🤣
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Nice work ! !
I find the same degree of high-end roll-off is needed on all my unity builds too.
(What delay did you find between dcx sections?)
I find the same degree of high-end roll-off is needed on all my unity builds too.
(What delay did you find between dcx sections?)
I couldn’t measure a discernible delay between the hf and mf on the coaxial. I’ve got a 0.9ms delay between the coaxial and 10 inch and another 7.1ms to the Tham 12
I finished my pair recently and they sound so good......
Currently I'm using it nearfield so the level I required is very low so I drive the DCX464 with MOTU M4's headphone amp for it.
And it still sounds phenomenal. I can't believe with a build in headphone amp from an audio interface less thant $300 can produce such great sound quality.
PA speaker will be my choice for speaker building in the future I think.
310hz from woofer to MF on the DCX, then 4k between MF and HF on dcx. I had the latter point at 3.5k originally but I saw a post suggesting 4k was better. After DSP the results were similar. I do have protection caps on the DCX. Btw the 310hz crossover is not ‘negotiable’ if you want to retain the benefits of a single apparent source in this synergy horn in this design… the separation of the woofer ports in the horn are too far apart to cross higher. (Same reason I had to go with the 464 instead of the lighter 354 I’d hoped to use)
Not sure where you’re getting 380hz from, but I measured the maximum distance between the centres of woofer ports in the horn as approx 28.5cm on my build which gives a minimum crossover to the compression driver of 300hz for a maximum of 1/4 wavelength spacing according to omnicalculator. My measurement is diagonally from the centre of one port to the other. I may have that wrong but it seemed to make sense to me.
I was just guessing from the graph posted on DIYRM, not a accurate value. From the graph it seems it's crossed at 400Hz, previously I use another app with similar scale to guess the crossover frequency by Scott.
If we calculate between 250Hz and 500Hz the 2nd line should be 250*2^(2/3) ～ 396.85Hz.
The 1/4 wavelength concerns me also for the tap port, not sure if that's so strict. Maybe I should try to cross lower in the future.
The original crossover setting from Scott has 2 2nd order high pass filter at 310Hz.
Thanks for the suggestion, I'm using it near-field so the volume is okay for me at the moment, but indeed MOTU's
headphone is really weak......when I tested it at higher volume it clipped very soon. The ASR measurement on it's headphone provides less than 30mW at 33Ohm load...
I'm still considering whether to go for Hypex Fusion amp or not for the next upgrade. Right now I'm using 1200AS2 for the woofer and passive crossover from B&C and drive them with MOTU's headphone amp. It's already sounds very very good so probably I'll use the setup for a short period of time. Thanks for the suggestion for the amp. The power input for 3e audio with PFFB can only up to 3x volt, not sure if I can use a zener diode to lower the voltage since my 1200AS2 has +- 68V for the hanger modules. The price for 3E is close to the hanger amp module from icepower. With the high sensitivity of DCX, I would like a amp that's with lower gain.
I don't have the woodwork skills so this box is done by others, the quality is far exceed my expectation.