Using car speakers in a bookshelf speaker.
Not a good idea, sourced these for the cost, however these cost upwards of $20 in some parts of the world, better to use 4 inch full ranges.
That said, they sound fine to me in my installation with EQ. Note also that the tweeters are suspect - they may not be actually doing anything.
Next buy.
Not a good idea, sourced these for the cost, however these cost upwards of $20 in some parts of the world, better to use 4 inch full ranges.
That said, they sound fine to me in my installation with EQ. Note also that the tweeters are suspect - they may not be actually doing anything.
Next buy.
An aperiodic enclosure is pretty forgiving in terms of driver type and enclosure volume, so is worth experimenting with.
Cut a series of narrow slots in the back of an otherwise sealed cardboard enclosure and cover them internally with soft felt.
For the 7 litre enclosure you mention, I suggest 6 slots, each 100 mm x 6 mm, placed 40 mm apart.
Scale up as necessary for larger enclosure volumes, which may give better results.
Thanks. Never heard of these before, but there is a thread I am looking at.
https://www.diyaudio.com/community/threads/show-your-aperiodic-speakers.378740/page-2
Will it improve bass response? I am thinking of experimenting with a slot at the front of the speaker.
Interesting: https://diyaudioprojects.com/Technical/Aperiodic/
https://www.diyaudio.com/community/threads/show-your-aperiodic-speakers.378740/page-2
Will it improve bass response? I am thinking of experimenting with a slot at the front of the speaker.
Interesting: https://diyaudioprojects.com/Technical/Aperiodic/
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The ventilated back reduces the amplitude of the Q of the single bass resonance hump of a sealed enclosure, which can reduce 'boominess'.
The bass performance may be described as resonant free, resulting in good transient response and an 'open' sound.
The limiting factor is the cardboard of course - the enclosure must be as rigid as possible.
A front slot would have to be carefully dimensioned to tune the enclosure in accord with the driver's resonant frequency and other parameters.
The ventilated back avoids the need to tune the enclosure. It permits experimentation rather than relying on mathematical precision.
When you look at the link you mentioned, you will see front slots which are packed with fibreglass. This is another method of aperiodic loading.
Just like in the Dynaco A 25 whose image I have attached.
The single large front slot should have an area equal to the sum of the areas of the multiple narrow slots in the rear of the enclosure that I dimensioned earlier.
EDIT: This method does require a decent thickness of front baffle to contain the wad of fibreglass.
Attachments
Yes, you can experiment with the number of narrow rear slots in order to obtain the best sounding bass response as judged by ear.
BasicHIFI1, you have quoted the following.
The aperiodic enclosure simply acts like it is a larger closed box. This is because the vent is not a leak but is resistive, causing damping. This causes a reduction in the resonance Q factor. The idea of better controlled bass is nothing more than the result of this, and as we know, that isn't always what we want. Rather, we want to reach some specific value to suit our application. That said, aperiodic is a way to save space.
This is not exactly what happens.
The aperiodic enclosure simply acts like it is a larger closed box. This is because the vent is not a leak but is resistive, causing damping. This causes a reduction in the resonance Q factor. The idea of better controlled bass is nothing more than the result of this, and as we know, that isn't always what we want. Rather, we want to reach some specific value to suit our application. That said, aperiodic is a way to save space.
I think I understand: the resistive effect of the air mass in a larger box is replaced by the reisistive effect of a port with air resistance due to a porous blocking material. That was quoted from a website.
Another constraint, if I have not mentioned it earlier, is that I am playing these speakers at < 70 dB at 1 metre, I like music loud, however the present situation does not allow it. Either its too loud or I can't hear other people calling, however I can set aside separate listening times.
Sometimes I also listen at very low sound levels when I am working on something so as not to distract me.
All in all, a sub-woofer or doing the bass first may be a good idea. Next.
Another constraint, if I have not mentioned it earlier, is that I am playing these speakers at < 70 dB at 1 metre, I like music loud, however the present situation does not allow it. Either its too loud or I can't hear other people calling, however I can set aside separate listening times.
Sometimes I also listen at very low sound levels when I am working on something so as not to distract me.
All in all, a sub-woofer or doing the bass first may be a good idea. Next.
That's not right either. The air mass is reactive, not resistive.
However another way to use resistance to make the box seem larger is to stuff it. It needs to be stuffed enough to begin having this effect, but not so much that the stuffing takes up too much space and makes the enclosure smaller.
However another way to use resistance to make the box seem larger is to stuff it. It needs to be stuffed enough to begin having this effect, but not so much that the stuffing takes up too much space and makes the enclosure smaller.
I haven’t actually pulled the woofer to confirm, but I believe the inside of the baffle has the same grill stapled in place to retain the fibreglass so you’re right about the baffle. I don’t know if there is any depth to the port.
You are correct, Cal, the fibreglass is compressed between a front and rear grill.
There is no depth to the port other than the thickness of the baffle.
There is no depth to the port other than the thickness of the baffle.
@BasicHIFI1
That calculator is very basic and much oversimplified.
How did you arrive at your entry for the "tuning frequency"?
That calculator is very basic and much oversimplified.
How did you arrive at your entry for the "tuning frequency"?
Fiber glass is a known carcinogen.
Be careful, see it it is totally enclosed, wear at least N95 mask.
Avoid dust.
Be careful, see it it is totally enclosed, wear at least N95 mask.
Avoid dust.
I selected the lowest frequency that would give me a manageable vent length 10 cm. I have tried it out with another cardboard speaker, sealed this time or semi-sealed, and it does make a difference, gives bass boost, however it does not have enough of an effect to be worth the effort. It is easier to use an open baffle with wings and use EQ. The larger speaker is better even with the rear panel uninstalled, so lots of variables.
Cardboard speakers are as good as you can make them.
It appears that you still have a lot to learn about fundamental loudspeaker enclosure design.
You may succeed in making a good cardboard enclosure if you go down the experimental aperiodic route.
You may succeed in making a good cardboard enclosure if you go down the experimental aperiodic route.
Indeed yes. Looking forward to it.
I first have to make an accurately cut set of sides. Folding will not do it.
U-shaped enclosure. Cardsonde 3U. With EQ it is quite listenable, also with bass manipulation of +15 dB. 10 should be enough. 3 is recommend.
The unit blends in well in the subdued indoor light. Also, some mp3 files need to be normalized they somehow have been distributed with very low volume.
The unit blends in well in the subdued indoor light. Also, some mp3 files need to be normalized they somehow have been distributed with very low volume.