No idea what to title this, first time posting on the thread. I found you on google but could not quite find what I was looking for.
I would like to make a 2.1 channel amp for use in a custom laptop using the raspberry pi. I have broken down a pair of old speakers (Insignia NS-PCS21) and placed them in a old shoe and made them run on 9v batteries to make it mobile. The speakers sound nice but I want a little more power from the bass. I am also thinking of making my own amplifier to supply more bass to the sub woofer. i would like to run the amplifier off of 9 volt power if it is at all possible.
Thanks for the future replies,
James
I would like to make a 2.1 channel amp for use in a custom laptop using the raspberry pi. I have broken down a pair of old speakers (Insignia NS-PCS21) and placed them in a old shoe and made them run on 9v batteries to make it mobile. The speakers sound nice but I want a little more power from the bass. I am also thinking of making my own amplifier to supply more bass to the sub woofer. i would like to run the amplifier off of 9 volt power if it is at all possible.
Thanks for the future replies,
James
Would something like this amp work for me if I build it, Circuit power audio amplifier with TDA7377 2.1 – Stereo + Subwoofer 2x 12 Watts + 37 Watts | Xtronic Free Electronic Circuits and Informations
James
James
Hi,
I think you would be looking at more cabinet design than just putting them in a shoe, in order to get more bass out of it
I think you would be looking at more cabinet design than just putting them in a shoe, in order to get more bass out of it
I plan on making the base of the laptop out of lexan and separating the two satellites and sub woofer, I am not looking to move it around that much but have the option for portability if I desire. The shoe box was a testing grounds to see if I can get them to run on battery power.
James
James
Ah. Shoe box.
You're making a laptop. You'll have to be a bit more explicit about the case. It's all about volume and shape. Tell us about the screen too...
You're making a laptop. You'll have to be a bit more explicit about the case. It's all about volume and shape. Tell us about the screen too...
The screen is a 15.6" touch screen, so i am looking to make the base of the laptop at least 16". I plan on putting the sub on the back of the base which will make the base probably about 5" high. Then probably about 10" for the depth to allow more sub space and for room for a keyboard.
James
James
I just got home from work and I swear that I said shoe box every time. Would be interesting to put speakers into an old shoe though 😛
James, look at speaker efficiency over more power since you are running off batteries.
Higher efficiency speakers will get you more volume. I have a Logitech Lapdesk from when I owned a laptop, it had tiny 1.5" drivers but the cabinet was large for the size and it ran off USB power - not more than a watt per channel, at best, but it was loud enough for lap usage.
Fountek makes some models that will hit 86dB/w, and Faital Pro promises even more efficiency if you can live with 3" speakers. The Neo magnet ones should be light enough for lap usage. Fountek's 2" models are also very good. Efficiency is slightly low though.
On batteries, consider using 18650 types in series - two will get you to 7.4V which is healthy enough for usage for both, and enough juice for a few hours of operation. Tablet batteries are also good options, those go all the way to 8-10000mAH. Not sure how you are feeding the power to the entire system, is this a 9V SLA?
The 7377 is a Class AB amp. For your power levels, try something in Class D for better battery life. I would ditch the sub. The base (your lap) is too compliant to get good bass out of any kind of sub. If you persist, however, Peerless has some nice models at 3" and 4" sizes, and you can point those downward. They can go to about 60Hz, which is great for that size. Any lower and the vibrations from it will knock your wooden leg loose 😀
Higher efficiency speakers will get you more volume. I have a Logitech Lapdesk from when I owned a laptop, it had tiny 1.5" drivers but the cabinet was large for the size and it ran off USB power - not more than a watt per channel, at best, but it was loud enough for lap usage.
Fountek makes some models that will hit 86dB/w, and Faital Pro promises even more efficiency if you can live with 3" speakers. The Neo magnet ones should be light enough for lap usage. Fountek's 2" models are also very good. Efficiency is slightly low though.
On batteries, consider using 18650 types in series - two will get you to 7.4V which is healthy enough for usage for both, and enough juice for a few hours of operation. Tablet batteries are also good options, those go all the way to 8-10000mAH. Not sure how you are feeding the power to the entire system, is this a 9V SLA?
The 7377 is a Class AB amp. For your power levels, try something in Class D for better battery life. I would ditch the sub. The base (your lap) is too compliant to get good bass out of any kind of sub. If you persist, however, Peerless has some nice models at 3" and 4" sizes, and you can point those downward. They can go to about 60Hz, which is great for that size. Any lower and the vibrations from it will knock your wooden leg loose 😀
Thanks for the reply, I will have to look into all that tomorrow as it is getting closer to bed. I plan on running them on 2 11.4 volt lipo batteries in parallel and splitting the power to 9v if i keep the current speakers and about 5.5v for the pi and screen and separate usb hub for more ports. I love bass so I wish to keep a sub. I am running normal 9v batteries with my current speakers. Two 9v batteries in parallel give me 6 hrs of run time. It runs around 1000mah. It would be nice to have a better sounding speakers with less power being drained.
Attached are some pictures of the box project.
Attached are some pictures of the box project.
Attachments
![20141112_214645[1].jpg](/community/data/attachments/416/416846-c3a2e7fb7b655438b4c5eb5f630f83ba.jpg?hash=w6Ln-3tlVD)
![20141112_221047[1].jpg](/community/data/attachments/416/416865-f445ab64a7014521dff8e0805d6d46fb.jpg?hash=9EWrZKcBRS)
![20141112_214722[1].jpg](/community/data/attachments/416/416889-59455442363744691d1a97eca746e336.jpg?hash=WUVUQjY3RG)
I choose to go with two Fountek FR58EX 2" Neodymium Full Range Speaker Driver and FaitalPRO 4FE35 4" Professional Full-Range Woofer 8 Ohm. Any idea on which amp would be best suited for this set up?
James
James
I picked up that amplifier you suggested, nice price. I ended up going with the Dayton audio nd105-8 but stayed with the original 2" drivers. said two of them would be more then loud enough for me to enjoy. Now any suggestions on the the enclosure? Instead of doing a lap to i am thinking of a large I pad like enclosure to fit the large screen. the screen is either going to 14 or 15.5" probably the larger one. i cant decide weather it would be cooler to mount the 2" drivers in the front next to the screen or on each side with the sub on the top of the box or mounted in the rear in the center of both. So box dimensions will probably be 15"x 10" x 8" with speaker drivers mounted on the side or 10 x 10 x 8 with front mount speakers. Would it be better for the sub to be ported or sealed?
James
James
Some of this will depend on the most comfortable arm position when the tablet is lying face up. This will give you the maximum possible thickness.
Watch your neck position. If the tab is too low you have to tilt your neck in almost impossible angles, and if it is too high you end up hunching your shoulders.
Once you have the thickness you can work out the total volume available to you. I strongly suspect you will need to stay sealed as the volumes will be too small for ported.
A car dash kind of layout would work also, where the console tilts up after the top of the screen so you get a little more volume for the rear chamber.
I am a fan of direct facing speakers. As close to on-axis as possible. That gives you the most accurate sound path (if the driver is designed for it, of course).
Watch your neck position. If the tab is too low you have to tilt your neck in almost impossible angles, and if it is too high you end up hunching your shoulders.
Once you have the thickness you can work out the total volume available to you. I strongly suspect you will need to stay sealed as the volumes will be too small for ported.
A car dash kind of layout would work also, where the console tilts up after the top of the screen so you get a little more volume for the rear chamber.
I am a fan of direct facing speakers. As close to on-axis as possible. That gives you the most accurate sound path (if the driver is designed for it, of course).
So do to choice of speakers and lack of money the raspberry pi is going to be used a portable media station with a 2.8 lcd display running raspbmc. I decided to go with a ported box around 13x13x12. My question now is will the electronics in the box distort the sound. Whats a good way to seal the raspi opening?
James
James
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