Hello guys!
I'm rather new to speaker building, so I'm looking for some input on a little project I'm preparing.
I have a set of DLS R5A 5.25" car drivers collecting dust after I sold my last car. I'm now planning to make an enclosure for these in order to use them at home or in the office.
The t-s parameters are the following:
(as listed in http://dls.se/files/59/1/specR5A_T25_2008.pdf)
Fs: 72.3 Hz
Re: 2.88 ohm
BL: 3.15
CMS: 579
QMS: 6.88
QES: 1.11
QTS: 0.95
RMS: 0.53
MMS: 8.35 grams
VAS: 6.09 liters/0.22 square ft
SD: 86.5 square cm
After simulating these in WinISD, it seems that they would need a really large box to give a somewhat flat frequency response. I suppose that's because car elements are designed for an infinite baffle setup. I'm attaching a screenshot of WinISD with three different enclosure sizes/types.
WinISD suggests a box size of 298 liters or about 10.5 qubic feet for a vented enclosure, which is way too large for desktop speakers 😉
A closed configuration with a size of about 30 liters/1.5 cu ft gives a "bump" of around 1.5 dB (qtc=1.0.050) around 105 Hz (yellow curve in picture). A vented configuration of the same size with a realistic port length seems to give a 2+ dB bump as well, but a lower F3 (orange curve).
I now have this idea that since it seems futile to get rid of this midbass peak by enclosure design, I would use DSP to equalize away the peak. Since I'd be equalizing anyway, it seems that I might as well go for a vented configuration that is tuned quite high, and then simply remove the midpass peak by DSP. It would seem to me that this gives me a more efficient speaker system than if I were to go with a closed design with a qtc of 1.05 and up.
Do you guys have any opinions on which kind of enclosure to choose given these drivers? I suppose I wondering mostly about the approach of making an imperfect enclosure good using DSP.
P.S. I'm thinking of getting something like the Audio Development Board for PIC32 MCUs (Audio Development Board for PIC32 MCUs) to make my own dedicated equalizer for these.
I'm rather new to speaker building, so I'm looking for some input on a little project I'm preparing.
I have a set of DLS R5A 5.25" car drivers collecting dust after I sold my last car. I'm now planning to make an enclosure for these in order to use them at home or in the office.
The t-s parameters are the following:
(as listed in http://dls.se/files/59/1/specR5A_T25_2008.pdf)
Fs: 72.3 Hz
Re: 2.88 ohm
BL: 3.15
CMS: 579
QMS: 6.88
QES: 1.11
QTS: 0.95
RMS: 0.53
MMS: 8.35 grams
VAS: 6.09 liters/0.22 square ft
SD: 86.5 square cm
After simulating these in WinISD, it seems that they would need a really large box to give a somewhat flat frequency response. I suppose that's because car elements are designed for an infinite baffle setup. I'm attaching a screenshot of WinISD with three different enclosure sizes/types.
WinISD suggests a box size of 298 liters or about 10.5 qubic feet for a vented enclosure, which is way too large for desktop speakers 😉
A closed configuration with a size of about 30 liters/1.5 cu ft gives a "bump" of around 1.5 dB (qtc=1.0.050) around 105 Hz (yellow curve in picture). A vented configuration of the same size with a realistic port length seems to give a 2+ dB bump as well, but a lower F3 (orange curve).
I now have this idea that since it seems futile to get rid of this midbass peak by enclosure design, I would use DSP to equalize away the peak. Since I'd be equalizing anyway, it seems that I might as well go for a vented configuration that is tuned quite high, and then simply remove the midpass peak by DSP. It would seem to me that this gives me a more efficient speaker system than if I were to go with a closed design with a qtc of 1.05 and up.
Do you guys have any opinions on which kind of enclosure to choose given these drivers? I suppose I wondering mostly about the approach of making an imperfect enclosure good using DSP.
P.S. I'm thinking of getting something like the Audio Development Board for PIC32 MCUs (Audio Development Board for PIC32 MCUs) to make my own dedicated equalizer for these.
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Hi,
Put them in sealed and stuffed boxes of about 8L to 10L.
High vented tunings simply overload when fed with low bass so
that is not a good idea. With no BSC (baffle step compensation)
the bass bump won't really be much of an issue, if at all.
TBH either keep it very simple, just put them in boxes, with
the x/o box screwed to the rear panel for desktop use with
a T-amp, or consider building some proper hifi speakers.
rgds, sreten.
undefinition
(see if nothing else, the excellent FAQs)
The Speaker Building Bible - Thread opened for edits/input. - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
Zaph|Audio
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
FRD Consortium tools guide
Designing Crossovers with Software Only
RJB Audio Projects
Jay's DIY Loudspeaker Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
A Speaker project
DIY Loudspeaker Projects Troels Gravesen
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design
Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Tool Folder
Put them in sealed and stuffed boxes of about 8L to 10L.
High vented tunings simply overload when fed with low bass so
that is not a good idea. With no BSC (baffle step compensation)
the bass bump won't really be much of an issue, if at all.
TBH either keep it very simple, just put them in boxes, with
the x/o box screwed to the rear panel for desktop use with
a T-amp, or consider building some proper hifi speakers.
rgds, sreten.
undefinition
(see if nothing else, the excellent FAQs)
The Speaker Building Bible - Thread opened for edits/input. - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
Zaph|Audio
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
FRD Consortium tools guide
Designing Crossovers with Software Only
RJB Audio Projects
Jay's DIY Loudspeaker Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
A Speaker project
DIY Loudspeaker Projects Troels Gravesen
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design
Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Tool Folder
Thanks a lot for your input sreten!
I will likely go with a closed enclosure as you say. If you don't mind me asking, is there a reason for the 8 to 10L volume suggestion (other than it being a nice size for desktop speakers)?
I was thinking that I could probably stretch to 16-20L without them taking up too much room if there is no special reason to go for the smaller size.
Again, thanks for the suggestions!
Regards,
Stefan
I will likely go with a closed enclosure as you say. If you don't mind me asking, is there a reason for the 8 to 10L volume suggestion (other than it being a nice size for desktop speakers)?
I was thinking that I could probably stretch to 16-20L without them taking up too much room if there is no special reason to go for the smaller size.
Again, thanks for the suggestions!
Regards,
Stefan
Hi,
As soon as the box size goes over Vas it makes less and less difference,
as the driver suspension stiffness becomes higher than the boxes.
16L to 20L sealed for a 6.1L Vas driver is simply too big.
If its desktop system use an EQ plug-in to equalise the low bass.
9L sealed and well stuffed is IMO simply a good compromise.
rgds, sreten.
As soon as the box size goes over Vas it makes less and less difference,
as the driver suspension stiffness becomes higher than the boxes.
16L to 20L sealed for a 6.1L Vas driver is simply too big.
If its desktop system use an EQ plug-in to equalise the low bass.
9L sealed and well stuffed is IMO simply a good compromise.
rgds, sreten.
Hi,
As soon as the box size goes over Vas it makes less difference,
as the driver suspension stiffness becomes higher than the boxes.
16L to 20L sealed for a 6.1L Vas driver is simply too big IMO.
If its desktop system use PC EQ to equalise the response.
9L sealed and well stuffed is IMO simply a good compromise.
I'd use a class T amp of around 20W / 4 ohm, no matter what
the specs say about power handling, that is plenty for nearfield
and enough to drive the unit into excursion limiting low down.
rgds, sreten.
As soon as the box size goes over Vas it makes less difference,
as the driver suspension stiffness becomes higher than the boxes.
16L to 20L sealed for a 6.1L Vas driver is simply too big IMO.
If its desktop system use PC EQ to equalise the response.
9L sealed and well stuffed is IMO simply a good compromise.
I'd use a class T amp of around 20W / 4 ohm, no matter what
the specs say about power handling, that is plenty for nearfield
and enough to drive the unit into excursion limiting low down.
rgds, sreten.
Thanks again sreten!
I see your point and will go with your recommendation of a roughly 9L box with stuffing. Indeed I also found the instruction sheet for the drivers, where they do recommend a volume of roughly 6-8L if you want to put the 5.25" woofers in a box.
In fact the wood has been bought and the project is ongoing
Regards,
Stefan
I see your point and will go with your recommendation of a roughly 9L box with stuffing. Indeed I also found the instruction sheet for the drivers, where they do recommend a volume of roughly 6-8L if you want to put the 5.25" woofers in a box.
In fact the wood has been bought and the project is ongoing
Regards,
Stefan
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