Re: I'm not sure if this is the right thread to add...
Greets!
Note that you can sim series resistance (Rg) in BoxPlot and other basic box programs my calculating a new, higher Qes to input:
Qes' = Qes*(1+Rs/Rvc), where Rs is the series resistance and Rvc is the driver's DC resistance, so:
Rs = (Qes'/Qes-1)*Rvc.
Answers:
1. Jensen thought so
: http://www.studiomaudio.info/onken.html
Note that when a vent is placed against and perpendicular to another boundary it acoustically doubles the effective radiating area and due to the larger end correction also makes it acoustically longer, so for a given Fb a slot vent's length can be reduced to 0.707x its original length.
2. Your design's high aspect ratio vents will add an acoustic resistive component (lowering Ql in BoxPlot), rolling off the bass somewhat, but such vents tend to have mechanical resonance issues and why they're broken up into multiples.
Note that due to the strong room mode excitation of 'stereo' corners, it's a good idea to tune the cabs ~ a half octave apart and low enough the higher of the two won't unload to smooth in-room response a bit. That, or tune them the same and use digital EQ to best match them to the room.
Anyway, once dialed in and the speaker/corner cavities are crammed with fiberglass insulation they should perform very well indeed.
GM
CLS said:
Greets!
Note that you can sim series resistance (Rg) in BoxPlot and other basic box programs my calculating a new, higher Qes to input:
Qes' = Qes*(1+Rs/Rvc), where Rs is the series resistance and Rvc is the driver's DC resistance, so:
Rs = (Qes'/Qes-1)*Rvc.
Answers:
1. Jensen thought so
: http://www.studiomaudio.info/onken.htmlNote that when a vent is placed against and perpendicular to another boundary it acoustically doubles the effective radiating area and due to the larger end correction also makes it acoustically longer, so for a given Fb a slot vent's length can be reduced to 0.707x its original length.
2. Your design's high aspect ratio vents will add an acoustic resistive component (lowering Ql in BoxPlot), rolling off the bass somewhat, but such vents tend to have mechanical resonance issues and why they're broken up into multiples.
Note that due to the strong room mode excitation of 'stereo' corners, it's a good idea to tune the cabs ~ a half octave apart and low enough the higher of the two won't unload to smooth in-room response a bit. That, or tune them the same and use digital EQ to best match them to the room.
Anyway, once dialed in and the speaker/corner cavities are crammed with fiberglass insulation they should perform very well indeed.
GM
CLS said:
Greets, part deux!
Major peaking plus as BoxPlot shows, it offers no driver protection against bottoming out as sealed does. WRT vented loading, this driver is theoretically much better suited for a ~55.5 Hz BLH alignment.
Anyway, as you raise Fb it can work well in either a ~max flat TL or ML-horn as BoxPlot implies.
GM
Re: Re: I'm not sure if this is the right thread to add...
Hi GM,
Thank you very much for the informative replies. I'm learning, happily
And now I got question about this:
Tuning 2 cabs to different frequencies makes me worry. Their group delays would differ with the tuning. At some particular frequencies, the "slower" one might have double delay time. How can we deal with this?
Hi GM,
Thank you very much for the informative replies. I'm learning, happily
And now I got question about this:
GM said:
Tuning 2 cabs to different frequencies makes me worry. Their group delays would differ with the tuning. At some particular frequencies, the "slower" one might have double delay time. How can we deal with this?
LOL !
The corner cabs in my own house give me huge peaks in 100Hz and 200Hz. (room is about 5mW x 6mD x 3.2mH) I use the "feedback destroyer" function in DEQ2496 to cut them.
Eventually I set the attenuations of the 1/60 oct. parameter EQ to more than 30dB! Without it, these booms are way too much to take. Totally unbearable. (meantime, the 3~4dB suck out at 40Hz, and +3dB bump at 32Hz are not so noticeable)
And now the TAD-Onken is designed for a friend (& of course in another different house/room), so that boom will probably move to other frequency....
But I'm still wondering the different tunning can reduce the room mode, as long as they sit at the corners. I mean, even if the cabs are sealed, the 100Hz/200Hz peaks are still there, aren't they?
The corner cabs in my own house give me huge peaks in 100Hz and 200Hz. (room is about 5mW x 6mD x 3.2mH) I use the "feedback destroyer" function in DEQ2496 to cut them.
Eventually I set the attenuations of the 1/60 oct. parameter EQ to more than 30dB! Without it, these booms are way too much to take. Totally unbearable. (meantime, the 3~4dB suck out at 40Hz, and +3dB bump at 32Hz are not so noticeable)
And now the TAD-Onken is designed for a friend (& of course in another different house/room), so that boom will probably move to other frequency....
But I'm still wondering the different tunning can reduce the room mode, as long as they sit at the corners. I mean, even if the cabs are sealed, the 100Hz/200Hz peaks are still there, aren't they?
Hello,
I had first in mind to build an high efficiency floorstander but after seeing some drawnings of onken cabinet, wich looks beatufull, I'm thinking about building one.
The driver:
http://profesional.beyma.com/ENGLISH/pdf/descarga.php?pdf=15XA38Nd.pdf
it's a 15 inch pro coaxial. SD=880sqcm
The excel spread sheet giveme around 200L with effective vent lenght around 12cm and vent area of 304sqcm, so this speaker is good for an onken cab.
I modeled the response, it's good and flat, but the cone excursione below tuning FR is going to past the xmax(4mm) after few watts. Ok the xmech is 28mm but I don't want a sound that is distorted or compressed.
What can be done about it? subsonic filter, someone have a schema for it? How it would effect the percieved low pass?
Thank you very much
I had first in mind to build an high efficiency floorstander but after seeing some drawnings of onken cabinet, wich looks beatufull, I'm thinking about building one.
The driver:
http://profesional.beyma.com/ENGLISH/pdf/descarga.php?pdf=15XA38Nd.pdf
it's a 15 inch pro coaxial. SD=880sqcm
The excel spread sheet giveme around 200L with effective vent lenght around 12cm and vent area of 304sqcm, so this speaker is good for an onken cab.
I modeled the response, it's good and flat, but the cone excursione below tuning FR is going to past the xmax(4mm) after few watts. Ok the xmech is 28mm but I don't want a sound that is distorted or compressed.
What can be done about it? subsonic filter, someone have a schema for it? How it would effect the percieved low pass?
Thank you very much
Jerry Calà said:
Greets!
Correct, or at least use an equalizer to roll off the BW below Fb. If you have a separate preamp, power amp you can insert it between the two: http://www.t-linespeakers.org/tech/filters/passiveHLxo.html or try this and set the HF cutout at its 99999 max: http://www.oliveaudio.com/calculato...&za=1000&zd=200&calculator=1&submit=Calculate
Don't know how to do it if you have a receiver with no built in sub-sonic filter.
Don't know, never used one.
GM
GM said:
Don't know.
In addition, from the adjustment and RTA display of DEQ2496, the 100Hz and 200Hz peaks seem independent. I mean, attenuating the 100Hz peak does almost nothing to the 200Hz one.
That living room is not a "sealed box". There's a big openning to the kitchen, and some other door way to other rooms. There's shallow hollow space above ceiling and the ceiling surface is sound absorbing material....
Maybe these factors make thing complicated.
Anyway, I've already moved out of that apartment, so that's no longer my problem. A new one is coming. though.
Ah! OK, the kitchen and other doorways/rooms are acting as cascading mufflers and any hollow spaces are acting as bandstop filters, so they are modulating/filtering the listening room's response while the damped ceiling is helping with its modes. Complicated indeed! Hopefully you can find an apt. that allows you to ~seal the listening room off.
GM
GM
Hi,
did anyone try the Presicion Devices PD1550 in an onken?
http://www.precision-devices.com/asps/uploads/super/14.pdf
Kind Regards
Hauke
did anyone try the Presicion Devices PD1550 in an onken?
http://www.precision-devices.com/asps/uploads/super/14.pdf
Kind Regards
Hauke
Greets!
You're welcome!
The 1550 is a heart attach serious prosound driver designed for high SPL vented woofer, mid-bass alignments and large compression horns, just not an Onken alignment, though if its Vas was twice as large it would work fine.
Anyway, just look at what drivers they were designed for: low Fs, low-medium Q and high Vas. In today's 'small' world though, Vas is reduced to keep box Vb as small as practical, so few current high SQ drivers have it and most are very expensive.
GM
You're welcome!
The 1550 is a heart attach serious prosound driver designed for high SPL vented woofer, mid-bass alignments and large compression horns, just not an Onken alignment, though if its Vas was twice as large it would work fine.
Anyway, just look at what drivers they were designed for: low Fs, low-medium Q and high Vas. In today's 'small' world though, Vas is reduced to keep box Vb as small as practical, so few current high SQ drivers have it and most are very expensive.
GM
What makes the Onken 'sound' is a lot of vent harmonics comb filtering with the driver's output (harmonic distortion), so it would either tend to 'tighten' up its presentation due to these being rolled off or make it worse with even more delay between the multiple sources. Only one way to know for sure though since the room and speaker placement will affect it so much.
For rear firing, a single low vent mach, but somewhat smaller, area vent should perform better overall.
GM
For rear firing, a single low vent mach, but somewhat smaller, area vent should perform better overall.
GM
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