(I searched for "car horn hornresp", but found no avail.)
Hey. (It's been a long time since I've been around here. Too much to do and so little time. )
Here is the situation: the son of a collegue at work, bought a second hand car a few months ago. Since he studies Car Mechanics, he had no problems fixing up the Opel Corsa from 1992 .
He put a new head unit with CD in it, but his father told me he then ran out of budget and he really wanted a loud system, so he asked me if I could come up with some suitable loudspeakers to give his kid as a x-mas present.
For efficiency reasons I immedeately tought of the Beyma AG8/N that are used in Cyburghs Viech's, but then it hit me to use the trunk space to put a folded horn in there. (My collegue assured me his son won't mind having no trunk space. )
Hence, the CarViech.
I know this is about car audio, but since my questions involve cabin gain, LF and the space the horn mouth radiates in, I tought it fit in here. To the moderators: feel free to move this thread if you think it is needed.
Space concerns: The panel separating the trunk from the passengers space measures 99 to 38 cm. The trunk is 44cm deep. If we take 20cm for the width of one Beyma driver, then we have 59*38cm for the combined horn mouth, or around 1100cm^2 mouth area for a single driver.
I made a *quick* sketch to fold the horn, and it should be possible to fold about 130-150cm of horn length into that space.
Hornresp gave me an SPL-plot for a 40Hz contour in 1/8 th space, but it starts to drop off around 50Hz. (See attached file for the Hornresp parameters.)
So ...
- Since it will probably be radiating in less than 1/8th space, should I try to aim for 40 or even 30Hz? Will the ripple still be acceptable?
- Is mouth area more important than horn length in a car? If I can tune lower, then I can fit more length inside and still get away with it. And an even lower freq at witch the cone movement goes to max!
- What would the influence of cabin gain be? I think it will mostly reduce the ripples in the SPL plot, since after the tuning freq it drops off too fast to get any lift. No?
I will try tomorrow to make a more accurate folding scheme so I have a better idea what tuning freq fits best inside the given volume and with a 1100cm^2 mouth, but if I can get a few tips on which freq/length to tune everything to, it would be greatly appreciated.
Hey. (It's been a long time since I've been around here. Too much to do and so little time. )
Here is the situation: the son of a collegue at work, bought a second hand car a few months ago. Since he studies Car Mechanics, he had no problems fixing up the Opel Corsa from 1992
. He put a new head unit with CD in it, but his father told me he then ran out of budget and he really wanted a loud system, so he asked me if I could come up with some suitable loudspeakers to give his kid as a x-mas present.
For efficiency reasons I immedeately tought of the Beyma AG8/N that are used in Cyburghs Viech's, but then it hit me to use the trunk space to put a folded horn in there. (My collegue assured me his son won't mind having no trunk space.
)Hence, the CarViech.
I know this is about car audio, but since my questions involve cabin gain, LF and the space the horn mouth radiates in, I tought it fit in here. To the moderators: feel free to move this thread if you think it is needed.
Space concerns: The panel separating the trunk from the passengers space measures 99 to 38 cm. The trunk is 44cm deep. If we take 20cm for the width of one Beyma driver, then we have 59*38cm for the combined horn mouth, or around 1100cm^2 mouth area for a single driver.
I made a *quick* sketch to fold the horn, and it should be possible to fold about 130-150cm of horn length into that space.
Hornresp gave me an SPL-plot for a 40Hz contour in 1/8 th space, but it starts to drop off around 50Hz. (See attached file for the Hornresp parameters.)
So ...
- Since it will probably be radiating in less than 1/8th space, should I try to aim for 40 or even 30Hz? Will the ripple still be acceptable?
- Is mouth area more important than horn length in a car? If I can tune lower, then I can fit more length inside and still get away with it. And an even lower freq at witch the cone movement goes to max!
- What would the influence of cabin gain be? I think it will mostly reduce the ripples in the SPL plot, since after the tuning freq it drops off too fast to get any lift. No?
I will try tomorrow to make a more accurate folding scheme so I have a better idea what tuning freq fits best inside the given volume and with a 1100cm^2 mouth, but if I can get a few tips on which freq/length to tune everything to, it would be greatly appreciated.
Attachments
Not gonna lie to ya here, I have no experience with horn-subs. On the other hand, I have built and installed MANY subwoofers in cars, trucks, and boats.
If I recall correctly the Opel is a small car. If the "kid" is in his teens I am assuming, and wants loud, why not just opt for a decent amp and big ported sub combo.
While I can appreciate your ideas for the horn sub and the challenge of the project, as most others here in this forum will as well I would think. I just think under the given circumstances...quick and easy would yield better results according to the teen in question.
If he doesn't care about losing his trunk and being loud is the key, then build a ported box as big as possible and tune it somewhere in the 25-35Hz range. If all out SPL one-note boom is the target, go big as possible and tune for the 40s-50s somewhere.
Noidster
If I recall correctly the Opel is a small car. If the "kid" is in his teens I am assuming, and wants loud, why not just opt for a decent amp and big ported sub combo.
While I can appreciate your ideas for the horn sub and the challenge of the project, as most others here in this forum will as well I would think. I just think under the given circumstances...quick and easy would yield better results according to the teen in question.
If he doesn't care about losing his trunk and being loud is the key, then build a ported box as big as possible and tune it somewhere in the 25-35Hz range. If all out SPL one-note boom is the target, go big as possible and tune for the 40s-50s somewhere.
Noidster
Hi theNoid!
Yes, it is a small car (even by European standards .) If I recall correctly it is his first car - he paid about 130$ without import taxes!!! for it - , after getting his drivers licence, so that guy will be around 18-19yo.
His father wants to pay 100€ max... I might get a car audio sub well below that - I think - , but I'm doubting if I could get an amplifier of the same wattage included under that price.
There are 2 tiny 2" drivers in the dashboard. I haven't seen them but I'm 'putting my hand into the fire' that the surround is completely deteriorated. So he would also need 2 new drivers, straining the budget even more. With my proposal it's an all-in-one approach where his headunit has ample power to drive it to his desired SPL.
Also, I don't want to put a decade old battery trough the job of driving that amp/drivers, especially while the engine is not running. Hence I went for the high efficiency design.
I made a more detailed sketch today, but since I sold my digicam a few days ago I can't put a pic online.
I came up with this (for *one* side):
- Throat area is 110cm^2 (unchanged)
- Mouth area is 910cm^2 (a bit smaller than the theoretical max, but I needed a small baffle to mount the driver in. No getting around that.)
- 4 segments, 180° folds, total length 145cm, 40Hz contour.
- BLH chamber is minimal. I guesstimated 1000 cc.
- some unused space next to the last fold, so he still has some trunk space for a few bottles of wine.
Here is the SPL plot from Hornresp for BOTH drivers, into 1/8th space. The ripple is under +-3dB, but inside a car I think the ripple will be even lower.
Very interresting curve. Didn't expect it to be that good!
theNoid, maybe you can give a good guess about how the curve would look with cabin gain? I'm interested in how much down it would be @30Hz, and if there would be a bump around an other freq and if it can be equalized if nessesairly.
Yes, it is a small car (even by European standards
.) If I recall correctly it is his first car - he paid about 130$ without import taxes!!! for it - , after getting his drivers licence, so that guy will be around 18-19yo. His father wants to pay 100€ max... I might get a car audio sub well below that - I think - , but I'm doubting if I could get an amplifier of the same wattage included under that price.
There are 2 tiny 2" drivers in the dashboard. I haven't seen them but I'm 'putting my hand into the fire' that the surround is completely deteriorated. So he would also need 2 new drivers, straining the budget even more. With my proposal it's an all-in-one approach where his headunit has ample power to drive it to his desired SPL.
Also, I don't want to put a decade old battery trough the job of driving that amp/drivers, especially while the engine is not running. Hence I went for the high efficiency design.
I made a more detailed sketch today, but since I sold my digicam a few days ago I can't put a pic online.
I came up with this (for *one* side):
- Throat area is 110cm^2 (unchanged)
- Mouth area is 910cm^2 (a bit smaller than the theoretical max, but I needed a small baffle to mount the driver in. No getting around that.)
- 4 segments, 180° folds, total length 145cm, 40Hz contour.
- BLH chamber is minimal. I guesstimated 1000 cc.
- some unused space next to the last fold, so he still has some trunk space for a few bottles of wine.
Here is the SPL plot from Hornresp for BOTH drivers, into 1/8th space. The ripple is under +-3dB, but inside a car I think the ripple will be even lower.
Very interresting curve. Didn't expect it to be that good!
theNoid, maybe you can give a good guess about how the curve would look with cabin gain? I'm interested in how much down it would be @30Hz, and if there would be a bump around an other freq and if it can be equalized if nessesairly.
Attachments
Wow, not getting much input here are ya? Welps, as mentioned when it comes to horns, I am lost, so I cannot help you there. On the other hand, as far as cabin gain goes, the smaller the ride the better. Your project car being pretty small should grant you a pretty good gain starting somewhere in the 70-90Hz range and should result in about a 12dB per octave gain as you go downward in freq's. These numbers are just averages and each car is going to be different per it's internal dimensions and such. Hope this helps some...
Noidster
Noidster
Hey thanks for replying.
Well, I have the final design here:
http://users.telenet.be/Hellhouse/public/CarViech-main.jpg
(3MP ... large picture!)
It seems that with all the horn folds I would need about 3 sheets of MDF (2500mm*1200mm) instead of one, so it is over budget and his father doesn't wants to fund it anymore. However, he will ask his son if HE wants to pay for the MDF and put the speaker together. That is why I made the plan above. I have spent my time anyway in drawing/calculating the CarViech, he can put *his* time in building it.
So this plan is free for everyone to use non-commercially. Actually I hope someone will try it and put some pics/reviews online. If my collegue's son builds one, I'll ask for some pics too.
As far as the cabin gain goes: if it starts a 12dB lift around 80Hz, then it should reach 30Hz (yeey!), but around 50Hz the bump might be equalized a bit I think.
I'll let you know if it gets tested in real life! thanks again.
joris
Well, I have the final design here:
http://users.telenet.be/Hellhouse/public/CarViech-main.jpg
(3MP ... large picture!)
It seems that with all the horn folds I would need about 3 sheets of MDF (2500mm*1200mm) instead of one, so it is over budget and his father doesn't wants to fund it anymore. However, he will ask his son if HE wants to pay for the MDF and put the speaker together. That is why I made the plan above. I have spent my time anyway in drawing/calculating the CarViech, he can put *his* time in building it.
So this plan is free for everyone to use non-commercially. Actually I hope someone will try it and put some pics/reviews online. If my collegue's son builds one, I'll ask for some pics too.
As far as the cabin gain goes: if it starts a 12dB lift around 80Hz, then it should reach 30Hz (yeey!), but around 50Hz the bump might be equalized a bit I think.
I'll let you know if it gets tested in real life! thanks again.
joris
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