Attempting a first time home speaker build. Electronics/wiring/soldering is all done. Figuring out the enclosure for the main speakers is kicking my butt. I'm using a cheap pair of 3way 6.5 car speaker. Too cheap to have a published Qes, Xmax, Vas, etc.
I realize this limits advice I can get (and this is a fools errand)... Id still appreciate any tips on these questions...
6.5" 3-way 4ohm car speakers (allegedly 150watt RMS, 90db, 100-18000hz )
1)What volume 'range' sealed enclosure?
2)What volume range ported enclosure?
3)What happens if either enclosure is too small?
4)How would no enclosure at all effect the sound (mounted on a board)?
5)How would using an 0.15cu ft open cube frame, with breathable-foam walls compare to everything else?
6)Any other tips on keeping these as small as possible?
I realize this limits advice I can get (and this is a fools errand)... Id still appreciate any tips on these questions...
6.5" 3-way 4ohm car speakers (allegedly 150watt RMS, 90db, 100-18000hz )
1)What volume 'range' sealed enclosure?
2)What volume range ported enclosure?
3)What happens if either enclosure is too small?
4)How would no enclosure at all effect the sound (mounted on a board)?
5)How would using an 0.15cu ft open cube frame, with breathable-foam walls compare to everything else?
6)Any other tips on keeping these as small as possible?
Hi and welcome to the forum!
Car speakers are best suited to sealed enclosures.
A volume of around 12 litres would be a 'rule of thumb' guess, and a starting point for experimentation*.
A larger sealed box might overdamp your speaker and produce a weak bass response.
A smaller sealed box might underdamp your speaker and produce a 'boomy' bass response.
*It is worth experimenting regarding the effect of enclosure volume by mounting your speaker in a selection of stout cardboard boxes before committing yourself to any woodwork.
Car speakers are best suited to sealed enclosures.
A volume of around 12 litres would be a 'rule of thumb' guess, and a starting point for experimentation*.
A larger sealed box might overdamp your speaker and produce a weak bass response.
A smaller sealed box might underdamp your speaker and produce a 'boomy' bass response.
*It is worth experimenting regarding the effect of enclosure volume by mounting your speaker in a selection of stout cardboard boxes before committing yourself to any woodwork.
Leaky sealed boxes. Sometimes they work best OB.
My advice would be as big as you can live with and be prepared to tweak once you hear it.
dave
Historically, mobile audio drivers are assumed to be in lossy doors, trunks, 'kick' panels, so require acoustically very large cabs, i.e. 'infinite' baffle if sealed and super large TL/horn cabs if vented, so often used in open baffle [OB] for HIFI/HT.
To get this means that normally Qts is > 1.0 with a relatively tiny Vas spec, though in recent years some high[er] end systems are more HIFI 'friendly' due to the extremely good sealing of new cars in general and high end ones in particular.
In short, OB or even no baffle is ideally preferred.
1-4, 6: All that said, assuming decent power handling [Xmax, not claimed electrical power], the new 'standard' is shifting towards acoustical small/tiny sealed and using DSP to shape its frequency response now that it's a relatively inexpensive option, so recommend making it as big as you can afford/tolerate and electronically tune it to 'taste' in room.
5: No clue other than the effective baffle width/height/depth of the cube can in theory sound more or less 'full' down in the mid-bass, lower mids depending on the other's effective baffle width/height/depth due to differing baffle step [BSC] response/room loading.
To get this means that normally Qts is > 1.0 with a relatively tiny Vas spec, though in recent years some high[er] end systems are more HIFI 'friendly' due to the extremely good sealing of new cars in general and high end ones in particular.
In short, OB or even no baffle is ideally preferred.
1-4, 6: All that said, assuming decent power handling [Xmax, not claimed electrical power], the new 'standard' is shifting towards acoustical small/tiny sealed and using DSP to shape its frequency response now that it's a relatively inexpensive option, so recommend making it as big as you can afford/tolerate and electronically tune it to 'taste' in room.
5: No clue other than the effective baffle width/height/depth of the cube can in theory sound more or less 'full' down in the mid-bass, lower mids depending on the other's effective baffle width/height/depth due to differing baffle step [BSC] response/room loading.
They can be very successful by emulating the 'leaky' conditions that old car speakers used to operate within.
https://diyaudioprojects.com/Technical/Aperiodic/Aperiodic-Enclosures.htm
Woew I more replies than I expected. Thank you!
some follow ups...
If I go with a sealed box, does the shape matter? i.e. do long narrow vertical 8"x 7"x 30-ish" speaker at the top move the faux floor as needed... it would be ideal to minimize table space (testing that that would be very easy and it would be upgradeable)
Also, how is "no baffle" different than an "open baffle"?
some follow ups...
If I go with a sealed box, does the shape matter? i.e. do long narrow vertical 8"x 7"x 30-ish" speaker at the top move the faux floor as needed... it would be ideal to minimize table space (testing that that would be very easy and it would be upgradeable)
Also, how is "no baffle" different than an "open baffle"?
Up to a point, no, as they are presumed to have a ~uniform particle density, but once a high enough aspect ratio is reached, then internal eigenmodes begin to develop and being sealed it would make it a 1/2 WL resonator, so assuming a 30" [i.d.] length = ~13543.3"_sec/2/30" = < ~225.72 Hz that without some stuffing will modulate the driver from behind, which in turn will comb filter out of phase with the driver's output.
Not sure what you mean by 'move faux floor', though due to these eigenmodes, the driver's offset along its length changes the frequency response as it moves down the pipe.
No baffle means just a suspended driver Vs one mounted on a baffle. What changes is its polar [off axis] response and as the baffle gets bigger the speaker's response will become increasingly flatter with decreasing frequency.
Not sure what you mean by 'move faux floor', though due to these eigenmodes, the driver's offset along its length changes the frequency response as it moves down the pipe.
No baffle means just a suspended driver Vs one mounted on a baffle. What changes is its polar [off axis] response and as the baffle gets bigger the speaker's response will become increasingly flatter with decreasing frequency.
Basically as others have said.
Car speakers tend to be designed for sealed box.
assume car door volume, depending on vehicle is maybe 1.4 to 2.5 cubic feet
or around 40 to 70 liters.
Yep shoot for a narrow baffle.
And to get the volume needed
A tall and average depth box.
You would want at least a few minimal braces.
Or add more elaborate window braces
maybe just line the box , or a bit of extra stuffing behind the driver.
How about using a basic 6.5" floor standing box
Of course you dont need the tweeter cutout or vent.
Just 6.5" cutout and the braces.
Volume would work well around 34 liters or 1.2 cubic feet.
Car speakers tend to be designed for sealed box.
assume car door volume, depending on vehicle is maybe 1.4 to 2.5 cubic feet
or around 40 to 70 liters.
Yep shoot for a narrow baffle.
And to get the volume needed
A tall and average depth box.
You would want at least a few minimal braces.
Or add more elaborate window braces
maybe just line the box , or a bit of extra stuffing behind the driver.
How about using a basic 6.5" floor standing box
Of course you dont need the tweeter cutout or vent.
Just 6.5" cutout and the braces.
Volume would work well around 34 liters or 1.2 cubic feet.
Some Focal ( out of my price range ) vehicle drivers of the same size have a vas of 9 liters, I presume they must have similar specs as they would ( presumably ) be interchangeable between vehicles of the same mounting dimensions. I'm currently using some 16.5cm car drivers in a double chamber aperiodic enclosure. I think that car speakers are designed with stiff suspension, to keep the voice coil centered whilst going over bumps and to stop over travel in leaky enclosures - this may result in reduced bass extension. Remember, you don't need much bass to fill a car, very little volume compared to a room. Can you share some pictures once they're done?
is this in anyway useful for enclosure sizing?
Today I made the open baffle, and 0.4cu ft boxes (I have a use for them if they don't work here. The PVC fencing makes it easy to seal and adjust, its not going to stay when I'm done.
This won't be done for a month. Its a small part of a big project.
I wrongly assumed cheap car speakers would all be ubiquitous (dozens of under $30/pair 6.5" speakers), the 3 pairs I bought all sounded pretty different, I kept the loudest.
Today I made the open baffle, and 0.4cu ft boxes (I have a use for them if they don't work here. The PVC fencing makes it easy to seal and adjust, its not going to stay when I'm done.
This won't be done for a month. Its a small part of a big project.
Braces are used to “improve” the radiation of the box itself, typically halving (something i avoid) the width of a panel, will push the potential resonance by a factor of 2. If you can get them high enuff they are unlikely to ever be exited so become moot. I also use the brace to share driver reactive energy across more speaker panels than just the baffle means g much less energy goes into the baffle and it becomes much les slikely to be induced to ringing.
http://planet10-hifi.com/planset/MarKen-A6-extents-030218.pdf
You can see the holey brace that couples the driver magnets to the back panel (and top and bottom). In these boxes the doubles-thick i-beam walls tend to be self-bracing.
dave
No, meant just a driver suspended in space when its Qts' is high enough: https://www.diyaudio.com/community/threads/newb-cabinet-design-help.384059/post-6966793
I've use car speakers in several of my speaker builds, and it takes a long, long time for the stiff suspension to loosen up, and the bass " fill out " - I've been using my current speakers for several months and the bass is still improving. I would recommend that you play lots of bass heavy music before you make too many adjustments.
What's your overall opinion on using car speaker for home theatre? ...is it still an upgrade from $50 bookshelves
It's difficult to say, my current speakers ( pictured ) sound sublime, but they need treble boost ( I removed the tweeter ), on most of the speakers that I've used car drivers, I've only used the mid/bass driver, often connecting two drivers in series with a small ( 1 Uf ) cap across the lower driver to increase treble, sometimes adding a fill in tweeter around the back. I generally use car speakers because they're cheep and readily available, proper hi fi drivers would probably be better.
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Car audio speakers cover a huge range of qualities.
The old GM/Delco 6x9 is quite decent. I have heard a lot of bad ones as well.
dave
The old GM/Delco 6x9 is quite decent. I have heard a lot of bad ones as well.
dave
I didn't mean the quality of the speaker, I meant performance of a car speaker in a living room... maybe this is a stupid assumption but any full range "5 star amazon car speaker should sound better than any built in tv speaker, right?
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I never had any of the Delcos in a car, only in th ehome (or outside).
I would not make that assumption with car vrs TV speakers.
dave
I would not make that assumption with car vrs TV speakers.
dave
My experience with inbuilt tv speakers is that they have very little bass, in the mid and treble they generally sound mediocre, but sometimes sound quite good ( I can only presume that at certain frequencies they have little resonances ). With car speakers you can have them spaced wider and hence give better stereo, plus better bass and a lot more power handling, I've recently measured the power consumption of my amp when playing music load at less than 1 watt, so you can imagine how load your car drivers will go.
Besides, cars drivers a a good introduction into making your own speakers.
Besides, cars drivers a a good introduction into making your own speakers.