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15'' +1.4'' Midtop build

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Teunos View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Teunos Quote  Post ReplyReply Direct Link To This Post Posted: 03 July 2014 at 7:27am
I wanted the cab to be as tight as possible around the 15" and horn so that determined the width at the front. The handle at the back was already planned and i set that width to 200mm. The first side panel at the front is actually straight and is the depth of the baffle plus 15mm for the suport piece on the back of the baffle. I wanted to do a two piece trapezoid and given the above criteria there weren't many options that would work/look good.

Edited by Teunos - 03 July 2014 at 7:27am
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ArthurG View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 03 July 2014 at 8:51am
Originally posted by Teunos Teunos wrote:

Thanks guys! @Daniel, these cabs will be actively powered. For now that will mean there will be two speakons on the back, but i might put amp modules in them at some point to make some fully capable tops i can deploy everywhere. The only passive components i will use for these is a dc protection 60uF 450v mkp capacitor.
how with a single part you kill your HF sound quality...
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Teunos View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Teunos Quote  Post ReplyReply Direct Link To This Post Posted: 03 July 2014 at 8:54am
Because you think the slew rate of the cap is too low?

Edited by Teunos - 03 July 2014 at 9:14am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 03 July 2014 at 10:33am
Originally posted by Teunos Teunos wrote:

Because you think the slew rate of the cap is too low?
put a cap in series with any HF driver and listen how you lose dynamics, details and clarity. The bigger the capacitance, the bigger the difference... The cheaper the capacitor, the bigger the difference...
make AB test and you will see by yourself
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Teunos View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Teunos Quote  Post ReplyReply Direct Link To This Post Posted: 03 July 2014 at 10:48am
I have read about this before, and would like to see/hear the prove myself. I will do some measurement and listening tests, but i already installed these caps on my bms coaxes and could not hear a difference at all, or maybe i'm just deaf (selectively?). The cap has a -3dB point around 250Hz on the 18sound driver and around the same on the bms coax, so as far as that is concerned it's roughly about what i need. (2 octaves below the xover on the 18sound and roughly 1 octave below that of the BMS).

Edited by Teunos - 03 July 2014 at 10:51am
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Teunos View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Teunos Quote  Post ReplyReply Direct Link To This Post Posted: 03 July 2014 at 12:39pm
So i don't really believe there is any difference whatsoever, or at least not significant enough to be measured or heard. I could not hear any difference so i measured it. This was made with Steps, using a E-mu 4040 soundcard set to 96kHz sampling rate. The microphone used was a calibrated Isemcon EMX-7150. Response was measured using 1/48th octave stepped sine.
Below the second and third order distortion is shown, D2 in blue and D3 in red. Take the 2nd order distortion above 10kHz and 3rd above 5kHz with a pinch of salt, i don't know how the response of this mic is above 25kHz.
And the frequency response (Edit: Eq'ed)


Edited by Teunos - 03 July 2014 at 12:40pm
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audiomik View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote audiomik Quote  Post ReplyReply Direct Link To This Post Posted: 03 July 2014 at 4:18pm
Teun
larger value capacitors can have greater series inductance due to their methods of construction, thus increasing ESR at higher frequencies.

This could be the effect reported by others in this thread perhaps.

A method of reducing ESR can be to parallel a number of smaller value capacitors to achieve improved performance.

Link to website which explains ESR

Looks though that the Vishay product that you have chosen doesn't suffer with high ESR within your usable frequency range

Mik

Edit: spelling and add link to explain ESR

Edited by audiomik - 03 July 2014 at 4:33pm
Warning! May contain Nuts
plus springs, washers, screws, etc, etc.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 04 July 2014 at 3:43am
Teunos,

You think a frequency curve is enough to say that a part is transparent or not ?
they are much more going on than that
anyway, if you did not find any difference during the listening test, then fine, do your stuff. The most important is that you are satisfied.
But, with the right equipment (good source, good converters, good amp), anyone can listen a difference between a HF connected direct to the amp and one behind an capacitor. I've done it many times and even the uneducated people see it in a A/B comparison. (with a switch, not changing a cable. Our hear  memory is reliable less than 30sec)
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Teunos Quote  Post ReplyReply Direct Link To This Post Posted: 04 July 2014 at 9:31am
Originally posted by ArthurG ArthurG wrote:

Teunos,
You think a frequency curve is enough to say that a part is transparent or not ?
they are much more going on than that.
No, i quote myself
Originally posted by Teunos Teunos wrote:

So i don't really believe there is any difference whatsoever, or at least not significant enough to be measured or heard
If there is any difference, which can be easily heard according to you, even by an untrained ear, then obviously there has to be some measurable quantity to represent said phenomena. I have measured the frequency response, phase response (and therefore impulse response and group delay) as well as distortion. All these quantities show no significant difference.
I have also measured yesterday the complex impedance of the circuit with and without cap and the impedance as well as electrical phase angle above the intended crossover point is almost completely unaltered, so the load the amp will see is also the same.
I can do Cumulative spectrum decay to see if there is any time smear?

As for me, i'm already satisfied by the (for me) non audible effect the cap has. By your empirical claim that there is much more going on however i am intrigued. As a physicist, i'd gladly be proven wrong, if there is scientific data to do so.

Edit:spelling


Edited by Teunos - 04 July 2014 at 9:31am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Audio_Stash Quote  Post ReplyReply Direct Link To This Post Posted: 04 July 2014 at 3:50pm
great job my friend, very good work indeed!
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ArthurG View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 04 July 2014 at 11:14pm
Teunos,

take these 2 capacitors:
http://www.bennic.com.tw/en/sounder/05mpt.asp
https://www.intertechnik.com/Shop/Cross-over-parts/Capacitors/Audyn-Cap-Plus/_PLUS-330-08_1768,en,280,46737

put them in series with any good HF comp driver. Measure their performance (freq resp, phase, impulse, distortion, waterfall, etc). I can go the limit of my test bench (for example 0.0001% for THD), their are 100% the same, and still, in A/B listening test, anybody can catch the difference, even an untrained hear... I've done it many times...


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Teunos Quote  Post ReplyReply Direct Link To This Post Posted: 05 July 2014 at 5:31am
But that is stupid, cause then you are claiming that although there is no measurable difference, an audible difference is present. Although i do not doubt your judgement, i am very agnostic towards this. Surely we are on a very slipperely slope if we can clearly HEAR a difference, but can not find a measurable quantity reflecting it. Since we have already had most of the usual quantities measured, what is this magic quantity? It it for me now purely a scientific question, rather than an apllied one for this project.

I will try to do csd and some other impulse related measurements on sunday.
Best regards,
Teun.
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