batata's link says the driver is approximately 11.5 cm (4.5") in diameter, so the PVC pipe must have an internal diameter greater than 4.5"
To give an idea of scale: The volume of a 30 cm (12") length of 5" internal diameter pipe would be around 4 litres.
How did you estimate that 2 L volume?
You included a photograph of the JBL Boombox 2 in post #1, and it measures a sizeable 48.5 x 20.1 x 25.7 cm (including the handle I guess). 😕
THANK YOU ALL FOR YOUR HELP!!! I built the pvc pipe speaker!!!! IT'S REALLY REALLY REALLY STRONG!!! The bass is so strong that the small glass windows of my furniture started dancing!!! And I still didnt even tune it!
Video: https://photos.app.goo.gl/pw72irKSmuHgguYZ9
I took a 1 meter long PVC tube with a 100mm diameter and attached the speaker using a 3D printed part to make the fit perfectly and I used a big rubbery o-ring to seal the connection!
Here is the picture of the ring attached to the speaker:
Here is the blue 3D printed part to make the connection very tight.
Here is everything assembled.
Pretty simple build, nothing fancy. The other side of the pipe I kept open:
I can assure you, the sound is pretty loud! I am amazed how better this was compared to the cardboard box! So far I spent no more than 30 dolars (speaker, mini amplifier and materials) and the bass is way better than my 50 dolars bluetooth speaker!
I have a few questions to you, but before that I wanna thank you so much for your kindness! You are trully amazing and creative!
1) leaving the other end of the pipe open produced the best and loudest sound. I tried closing it with a pillow, with plastic using a rubber band (picture below), I tried closing it half way... everytime I closed it, the sound would drop a lot and the bass would almost disappear. Why that? I read a lot about sealed enclosure and they should provide a better sound...
2) I spent 5 dolars to buy this tube and I afraid of cutting it and the sound getting worse... Anyway, I will git it a try and cut... but where do I cut? It has 1 meter now... should I cut it in the middle? 30cm long? The JBL BOOMBOX (which is where this is speaker belongs) is 40cm wide (I measured it in the store) but it has 2 speakers and 2 tweeeters... I intend to have only 1 speaker and 1 tweeter...
3) Some people said I should put something inside the tube to create a resistance to air inside the enclosure so this could simulate a larger box... I tried putting a nylon foam inside and the sound got a little lower and less bass... so it was not better.
4) The tweeter is supposed to arrive today. I am afraid of installing it in the other end of the pipe because everytime I closed that end with anything, the bass would go away... I am thinking about keeping that other end open... so where should I put the tweeter? maybe at the middle making a perpendicular hole?
Video: https://photos.app.goo.gl/pw72irKSmuHgguYZ9
I took a 1 meter long PVC tube with a 100mm diameter and attached the speaker using a 3D printed part to make the fit perfectly and I used a big rubbery o-ring to seal the connection!
Here is the picture of the ring attached to the speaker:
Here is the blue 3D printed part to make the connection very tight.
Here is everything assembled.
Pretty simple build, nothing fancy. The other side of the pipe I kept open:
I can assure you, the sound is pretty loud! I am amazed how better this was compared to the cardboard box! So far I spent no more than 30 dolars (speaker, mini amplifier and materials) and the bass is way better than my 50 dolars bluetooth speaker!
I have a few questions to you, but before that I wanna thank you so much for your kindness! You are trully amazing and creative!
1) leaving the other end of the pipe open produced the best and loudest sound. I tried closing it with a pillow, with plastic using a rubber band (picture below), I tried closing it half way... everytime I closed it, the sound would drop a lot and the bass would almost disappear. Why that? I read a lot about sealed enclosure and they should provide a better sound...
2) I spent 5 dolars to buy this tube and I afraid of cutting it and the sound getting worse... Anyway, I will git it a try and cut... but where do I cut? It has 1 meter now... should I cut it in the middle? 30cm long? The JBL BOOMBOX (which is where this is speaker belongs) is 40cm wide (I measured it in the store) but it has 2 speakers and 2 tweeeters... I intend to have only 1 speaker and 1 tweeter...
3) Some people said I should put something inside the tube to create a resistance to air inside the enclosure so this could simulate a larger box... I tried putting a nylon foam inside and the sound got a little lower and less bass... so it was not better.
4) The tweeter is supposed to arrive today. I am afraid of installing it in the other end of the pipe because everytime I closed that end with anything, the bass would go away... I am thinking about keeping that other end open... so where should I put the tweeter? maybe at the middle making a perpendicular hole?
@JMFahey thank you for all the data you brought on your post! One thing I started laughing was when my glass window of furniture started shaking and I remembered your words "No wall shaking Bass of course." kkk Despite the walls are not shaking, I am very impressed with the results. I took a look at the hear of the magnet of the speaker and it has no information, just a random number written by hand. I took a picture of the front with a ruler so you can see dimensions:
@Galu I estimated 2L because when I went to the store to see the JBL BOOMBOX (I talking here about the version 1, the version 2 you told me was not available in the store I went) I imagined a 2L Coke bottle inside the JBL BOOBOX and I am almost sure it would fit inside of it... But doing the math with the dimensions you told about the JBL BOOMBOX 2, it would result in 25 L! My tube is 31 L => PI x Radius ^2 x 1 meter long x 1000 (conversion) => (3.14 x 0.1 ^ 2 x 1 x 1000).
@Galu here is a picture of a person holding the JBL BOOMBOX 1, it's not much bigger than a 2L coke botthe, right? Despite that, I checked the dimensons of it and it says 495 x 254.5 x 195.5 mm = 24 LITERS! How??? 24 Liters would be 10 coke 2L bottles... is my math that bad?
@Galu I estimated 2L because when I went to the store to see the JBL BOOMBOX (I talking here about the version 1, the version 2 you told me was not available in the store I went) I imagined a 2L Coke bottle inside the JBL BOOBOX and I am almost sure it would fit inside of it... But doing the math with the dimensions you told about the JBL BOOMBOX 2, it would result in 25 L! My tube is 31 L => PI x Radius ^2 x 1 meter long x 1000 (conversion) => (3.14 x 0.1 ^ 2 x 1 x 1000).
@Galu here is a picture of a person holding the JBL BOOMBOX 1, it's not much bigger than a 2L coke botthe, right? Despite that, I checked the dimensons of it and it says 495 x 254.5 x 195.5 mm = 24 LITERS! How??? 24 Liters would be 10 coke 2L bottles... is my math that bad?
Your photo above shows a JBL Boombox 2.
Its internal volume will be around 20 litres I would guess, since the stated dimensions will include the handle
Its internal volume will be around 20 litres I would guess, since the stated dimensions will include the handle
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Tweeter arrived!! It's pretty small but very loud. Playing it togethr with the speaker is awesome! I cant believe how cheap this build was... Here in Brazil, JBL BOOMBOX is 480 dolars! I spent so far less than 50 dolar on this build with one speaker and one tweeter... the profit JBL makes is huge, over 100%... I couldnt believe how cheap and nice this built became! Now my next task is cutting this pipe... I have no idea which size...
Good work in fitting the driver to the PVC tube! 😎
You have created an open-ended pipe speaker (closed one end, open the other).
The speaker will be loud, but the bass will be boomy. The bass frequencies that will be boosted will depend on the length of the pipe.
There's a patent by P.G.A.H. Voigt on such a speaker where the driver is mounted one-third of the way along the pipe.
Correction:
The Voigt column has one end closed and the other end open. The driver is mounted one-third of the way along the length of the column.
The Voigt column has one end closed and the other end open. The driver is mounted one-third of the way along the length of the column.
If I've got my physics right, the pipe resonates at a fundamental frequency equal to the speed of sound divided by twice the length of the pipe.
For your 1.0 m pipe, this resonance will boost the bass at a fundamental frequency of 340 m/s divided by 2.0 m = 170 Hz (along with its harmonics).
The result is an unevenly boosted bass response that could be described as "lumpy". However, if it suits you...
If you half the length of the pipe, the fundamental frequency of resonance would double to 340 Hz - not the result you will be looking for!
P.S. Your exploits bring back memories. I remember experimenting with a small speaker driver mounted at one end of a perspex tube back when I was a teenager!
The idea was well known then as a method of boosting the volume from a pocket transistor radio, and commercial versions were available for sale - see attachment.
The idea was well known then as a method of boosting the volume from a pocket transistor radio, and commercial versions were available for sale - see attachment.
Attachments
Sorry Friend but your Math is terrible 😱 😉
means its diameter is 100 mm or 10 cm
Its radius is 5 cm
Tube length is 100 cm
So tube volume is Pi*5^2*100=7850 cc so 7.85 Liters
FWIW estimated JBL Boombox is about
Since it´s a tube I´ll take the smaller "diameter" measurement, so:
3.14*9.5^2*49=13885cc so 13.9 liters.
In practice, since ends are somewhat rounded, some internal space is taken by speakers themselves, batteries, electronics,etc. , I expect some usable 10 liters or so.
As you see, all original volume suggestions were on spot 😉
One would think that Forum members have already built a cabinet or two before 😉
If you can, do NOT cut that tube, you will lose bass.
Agree that you have a strong 170Hz peak.
Normally to be avoided but in such limited power and size projects, "anything helps"
Notice the DSP curve I showed above, it had a 12-15dB peak 😱 at some 80Hz ... you are boosting its first harmonic.
"Synthetic Bass"?
Yes, definitely.
Should you kill it?
Not necessarily in the intended application, doubly so because at some point it will be used outside, in open air.
Again, congratulations on your build.
Memories here too.
The very first SS power amp I built was the output section circuit of a car radio, 2W RMS, Class A, fed 12V, choke loaded single ASZ15 (or similar), in the late 60´s
It worked finger blistering hot (literally) and I went through a couple of them, until shop salesman asked: "isn´t your heatsink too small"?
"Heatsink? what heatsink?" 😱 🙁
Plugged into a "Difusor Tupan", a cardboard tube with a single 4" speaker at one end, sold exactly for that, to improve pocket transistor radio sound ... which of course it did.
A popular local DIY version (using a cheap cardboard tube):
Do not open it specially for that, but if someday you have that speaker in your hands, I would love to have these dimensions (in mm): magnet diameter and thickness, top plate thickness.
I want to clone that speaker.
I guess 82-90mm diameter by 25 mm thickness, and about 6mm plate but in any case "measuring rules"
Also guess a 25mm voice coil.
Won´t get that unusual inverted dome cone in Argentina, but any decent regular one should do.
I guess 82-90mm diameter by 25 mm thickness, and about 6mm plate but in any case "measuring rules"
Also guess a 25mm voice coil.
Won´t get that unusual inverted dome cone in Argentina, but any decent regular one should do.
@JMFahey thank you so much!!!! Today I finished the pipe, painted and it sounds great! I cant believe how cheap this was and how much I would have to spend on a JBL Boombox... also, the mini amplifier handles both speakers very well, no thermal shutdown... I cant belive this small amp worked so great!
Regarding the measures you posted of the speaker, I measured it right now and it is 88mm wide (diameter), the magnet is 27mm thick and the shine thing is almost 5mm (your measures were almost perfect, very good eye!!!).
Thank you so much guys, you were all very kind and generous!!!
Regarding the measures you posted of the speaker, I measured it right now and it is 88mm wide (diameter), the magnet is 27mm thick and the shine thing is almost 5mm (your measures were almost perfect, very good eye!!!).
Thank you so much guys, you were all very kind and generous!!!