Measure the response of each and you may find out the capacitor may not be doing what you think it should be doing..
I used to use series capacitors for DC protection of high frequency drivers, with a value that should put the 1st order cap's X/O ~one octave below the fourth order crossover.
Here's what the raw response of an EV DH1AMT-16 (3" 16 ohm diaphragm) on a Paraline MEH looked like with (green trace) and without (white trace) an 18mfd series capacitor:
The capacitor didn't do anything resembling a 6dB per octave slope anywhere in the response, but had an effect all the way up to ~6kHz.
Art
Yes, you are right.
Your plots seem quite a bit more energy everywhere for the Nocap.
Here are mine, measured at 1m from mouth.
The Cap is crossing slightly lower and with more energy.
I changed the DSP X/O to 770Hz
Of course still a bit more energy with the cap.
They track very closely - pretty much identical above 2KHz.
Will evaluate back to back this evening..
I also changed the XO point for the THs.
Down to 60Hz and 4th order.
Plot from listening spot
This cleaned up the bass as the SH50 LF and THs were overlapping a bit too much, even for a bass head like me 😃
Will check the phase alignment next time and see if that slight dip at 60Hz budges.
Your plots seem quite a bit more energy everywhere for the Nocap.
Here are mine, measured at 1m from mouth.
The Cap is crossing slightly lower and with more energy.
I changed the DSP X/O to 770Hz
Of course still a bit more energy with the cap.
They track very closely - pretty much identical above 2KHz.
Will evaluate back to back this evening..
I also changed the XO point for the THs.
Down to 60Hz and 4th order.
Plot from listening spot
This cleaned up the bass as the SH50 LF and THs were overlapping a bit too much, even for a bass head like me 😃
Will check the phase alignment next time and see if that slight dip at 60Hz budges.
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I think if one listen to the HF driver only it is just basically that you hear some more LF. The real test is "in system" and EQed equally flat using 1st or n:th order XO.
//
For completeness here are the X/Os (used and not used) and PEQs used
HF BMS4550
(Cap in use)
MF 4 X Celestion 5" sealed back
(No X/O used)
LF 2 X Eminence Kappa 12A
(1st order used to assist phase alignment, together with 180deg out of phase polarity reverse)
Tapped Horn 15" Eminence Kappa Pro LFII
I also have a global -10dB PEQ on the input side as that room mode is excited be the Tapped Horns big time, the SH50 LFs a bit and even the MFs a tiny amount.
HF BMS4550
(Cap in use)
MF 4 X Celestion 5" sealed back
(No X/O used)
LF 2 X Eminence Kappa 12A
(1st order used to assist phase alignment, together with 180deg out of phase polarity reverse)
Tapped Horn 15" Eminence Kappa Pro LFII
I also have a global -10dB PEQ on the input side as that room mode is excited be the Tapped Horns big time, the SH50 LFs a bit and even the MFs a tiny amount.
Around 4-5dB more, but still with an acoustic response greater than 24dB per octave.
How does the raw response compare to the cap?
I took 3 measurements
In blue the Raw, no cap or DSP XO.
In red the cap, value calculated to give 1st order 800Hz (cap values checked on my L/C meter).
In green the DSP BW 1st order, set at 770Hz to give a similar slope point.
Can hardly see any difference between Raw and Cap.
Cap is not doing anything?
At my modest in room dB levels the BMS 4550 is in no danger.
I rarely see even 85dB, C weighting, fast response!
That's when I'm demoing something, normal listening is less.
What thinks?
I still prefer the cap to the DSP🙂
Hi @speedysteve and congratulations for your builds ! 😎😎😎
I am completerly stranger to the technology of "MEH" loudspeakers....
My apologies if I come with dumb, basic "right / wrong" questions 😕 on the subject, but...
1 - if I understand, the MEH principle is a large "wide band" horn, in which all the required High / Mid / Bass speakers or drivers are all included in or near the throat ?
2 - I do not see clearly in your pictures, but it seems that there is a cabinet around the horn to make the suitable enclosure for the bass driver installed in the horn ?
3 - the bass speakers do not have their complete SD looking into the horn, but solely through a hole, like to build a compression chamber ?
4 - looking to the EV MTS MEH speaker, there seems to be a lateral speaker which is not going into the horn, conversely to yours ?
Thanks for enlightening me a bit on that unusual (at least to me) kind of speakers !
T
I am completerly stranger to the technology of "MEH" loudspeakers....
My apologies if I come with dumb, basic "right / wrong" questions 😕 on the subject, but...
1 - if I understand, the MEH principle is a large "wide band" horn, in which all the required High / Mid / Bass speakers or drivers are all included in or near the throat ?
2 - I do not see clearly in your pictures, but it seems that there is a cabinet around the horn to make the suitable enclosure for the bass driver installed in the horn ?
3 - the bass speakers do not have their complete SD looking into the horn, but solely through a hole, like to build a compression chamber ?
4 - looking to the EV MTS MEH speaker, there seems to be a lateral speaker which is not going into the horn, conversely to yours ?
Thanks for enlightening me a bit on that unusual (at least to me) kind of speakers !
T
Hi Steve,
If you change the left hand (dB) scale to zoom in a bit it can make it a bit easier for comparisons, at the moment everything looks smooth. You only need to display -10dB to -60dB.
It helps a lot with EQ measurements as well.
For example, here's my 4550 on a 50x50 horn the same size as the SH50. 1/24 octave smoothing
Regards,
Rob.
If you change the left hand (dB) scale to zoom in a bit it can make it a bit easier for comparisons, at the moment everything looks smooth. You only need to display -10dB to -60dB.
It helps a lot with EQ measurements as well.
For example, here's my 4550 on a 50x50 horn the same size as the SH50. 1/24 octave smoothing
Regards,
Rob.
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Hi again @Speedysteve7 : sorry to derail your thread a bit by my noob questions, but I have found enough information in the meantime on the web to understand what a Multiple Entry Horn is, how it seems to work, and its plus and minus...
My apologies & renewed congratulations ! 😎
T
My apologies & renewed congratulations ! 😎
T
Correct, the cap is not doing anything in the acoustic crossover range, may be affecting the phase.
Unless you turn it up.
I think crossovers should provide protection 😉
Yes, I get a flatter phase plot with the cap.
Better that 800Hz than 900 or 954Hz too.
Not a huge difference but it's there.
The higher the frequency, the closer to the throat the drivers exit is. Bass drivers may be located near the mouth.
Yes.
The reduced area provides a more consistent horn wall than the typical vibrating membrane.
The Sd is reduced so the exit is a closer to a single point source at the correct acoustical loading point of the horn. The enclosed volume creates an acoustical band pass.
The side mounted speakers are used with DSP processing to provide a cardioid radiation pattern at lower frequencies where the horn becomes omnidirectional.
The MTS have models without that feature.
Yeah, I forgot to change to 1/6th or greater res on these last few. But that was not really what was under the microscope this time.
Yes, agree for my S2s, the BMS are expendable (bond villan laugh) 🙂
I would not go on the road like this..
Thanks for answering all the questions - better than I could👍
Yes the cabinet (of right approx volume) brings the 4 woofer ports into play as a bass reflex.
So you get part horn loading from the taps over the driver cones and part reflex from the ports..
Really clever design - hats off to Tom Danley.
I prefer this mid bass to all the straight mid bass horns I've built - admittedly, I've never had the room for a really colossal size - even the largest 1.7m long didn't reach down like the SH50s, or have the same punch.
They only had 1 X 12" per channel...
They still require a TH or two to do the low stuff..
New Here, after reading various threads and seeing the wisdom from Art and others, I am curious if anyone has build a smaller end active Synergy to act as booth monitors?
It would nice to use 5 or 8" drivers for the LF to keep the size down, but I am not sure if the MEH would preform well at those sizes?
It would nice to use 5 or 8" drivers for the LF to keep the size down, but I am not sure if the MEH would preform well at those sizes?
The Danley SM60Fs use 2 X 8" LF.
'Quite' a small package.
Get down pretty low too.
I considered making something like them for a while, 2x8" LF but 4x3" or 3.5" MFs and compression driver - driver topology like the SH50s.
But the SH50 alikes I made fit nicely with my big screen and pass size wise by the console holding all the gear, when in Cinema mode + and a BIG PLUS it is too - I love the sound and impact the 2x12" LFs make.
I may make a pair of SH60 using the same drivers I have, just to compare.
I can probably even reuse the rear enclosures to save time and wood 🤞
I did🙂 https://www.diyaudio.com/community/threads/2-way-synergy-inspired-by-spl-runt.378456/
I love them - they are "active" using external amps and DSP. One might fit in a DSP plate amp with a slightly deeper external box.