I was more thinking about the fact that Amp9-b has 4 output channels, while Amp6-b has 2. And because of the genius parallel-wiring of the Boominator, it was actually favorable to have only 2 outputs for 4 speakers, so the speakers went from 8ohm to 4ohm. But...
...will this work on the Amp9-b? I understand that it is possible to only use 2 channels of the Amp9, but does that mean that it will become 2x100W instead of 4x50W? If it will only be 2x50W half of the watt will obviously be unavailable to us.
But if we connect a speaker to each channel, it will not be possible to parallel-wire them as we do now, losing the big advantage of 4ohm.
Can you confirm this? Or is there a way to wire it all up in a way that will provide the full total 200W, while keeping the speakers paralleled for 4ohm?
What is the reason you are not using it in 24V mode? That was my original idea to begin with, to get the maximum power for the speakers, resulting in higher volume, right? We have 2x 12V SLA's in our Boominator, so we could just wire them in series to get 24V. I don't suppose this will use more power when at same volume levels as our old 12V solution.
Sorry if these are stupid newbie questions, but I am still a newbie to this
Output power and consumption varies with voltage. With the same voltage every amplifier will have the same output power. The amp9 will output the same as the amp6 per channel on the voltage so you get nothing from keeping it at 12V. That wasn't my point though. I want to use active filtering so I have a channel for both tweeter and woofer separately on both sides.
The ingenious part is that the tweeter filter will be a stopband filter, and you can connect a passive external subwoofer to those 2 channels. The tweeters will also be connected in series to lower the sensitivity by 6 dB (those I will use are 101dB sensitivity so they'll match the woofers) and avoid using a series resistor. It'll only have a series cap on the passive side after the amp.
The woofer output will remain unchanged. This setup will make sure that you can play slightly louder without using very much extra power. And that you can connect a passive subwoofer directly to it for more bass extension when you have a big party.
Unfortunately when you double the voltage (from 12V to 24V) you not only quadruple the output power but also the consumption. And battery times below 9 hours from 2 12V 7Ah SLAs is completely unacceptable to me.
Ahaa, so it is mostly because of new features to your Boominator that you want the Amp9. And the features do sound nice!
I think that we will go with louder volume if we can.
Okay, I didn't realize that. However, when a 24V Amp9 vs. a 12V Amp6 are playing at the same percieved volume, they will (hopefully) consume the same amount of power?
The difference would then be that we could turn up the Amp9 further when the Amp6 would top-off, and of course increase the batteri consumption too?
Since we will keep the volune lower than what an Amp6 is capable of most of the time anyway, the battery should still last a long time.
I think that we will go with louder volume if we can.
Okay, I didn't realize that. However, when a 24V Amp9 vs. a 12V Amp6 are playing at the same percieved volume, they will (hopefully) consume the same amount of power?
The difference would then be that we could turn up the Amp9 further when the Amp6 would top-off, and of course increase the batteri consumption too?
Since we will keep the volune lower than what an Amp6 is capable of most of the time anyway, the battery should still last a long time.
Yes, you are correct. Though the amp9 does use a bit extra power than the amp6 even at the same volume because of slightly lower effeciency and slightly more than twice the idle consumption.
I will effectively do the same as you except that the higher voltage will be 18V (technically 19.2V from 6 LFP cells) and not 24V, and will be feed to the Boominator from the passive sub. So that it's only when you go into party mode by connecting the sub you have the option of playing really loud (well, louder, since the Boominator is already really loud by itself).
18V is twice the output power of 12V but technically there'd be no problem in feeding it 24V from the sub either. I just think it's a more elegant solution to have 2 different batteries. One set permanently in the Boominator and one permanently in the sub so they can be recharged seperately as needed.
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That was what I was hoping to hear
Too bad about the lower effeciency and higher idle consumption, but I know these amps are great compared to others anyway Regarding your design, it sounds very exciting to have the seperate sub. I think I will suggest this possibility to the others from my camp, but we would most likely not include the Sub this year, but we could however maybe prepare for a sub-expansion by building the boominator itself like you do, so it is ready to connect to a sub, and then maybe mext year just build the sub. We'll see.
Anyway, I think I got the answers to most of my questions for now, and we will begin to design it with the Amp9. I will check this thread regularly though, to see if there are any news with your Boominator mkII, and we will surely have more questions as we progress.
I'm also looking forward to the google sketch-up
Thanks a lot!
I don't think there is any guide, if that is what you are thinking about. You should read this thread, which would probably give you all the information you need, although I know there are a lot of different suggestions and strange numbers to comprehend. If you make one which is roughly the same as Saturnus' original Boominator, then it should last a very long time, both physically and battery wise.
I small to-do list/guide would probably be like this:
1. Look at the pictures of Saturnus' Boominator to get an idea of what it is and will look like. (Two speakers and tweeters on each side, a seperate compartment in the middle for batteries and amplifier. The speakers are glued together magnet-to-magnet to enhance efficiency, and held in place by a piece of wood in the middle of each of the two speaker compartments, but without seperating the compartments, since they should share the volume (I think it's about 23 liters or something). Read and understand parallel and serial connections of the speakers and tweeters.) This is the way we did it, but Saturnus' internal design probably differ somehow.
2. Find it's dimensions in this thread, and get the wood needed to make the box.
3. Find the parts needed. (i.e. amp6-basic, 4x HP-10W speakers, 4x Zomax piezo tweeters, speaker cables, mini-jack cable for mp3-player, 12v SLA battery/batteries, amorphous solar cell that will fit the dimensions of the boominator if built in.) There are other stuff needed too, like volume knob, resistors for tweeter crossover and stuff, but you will find these while reading the thread.
4. Start building! Since there's no guide, you will probably have to do some things your own way, like fitting the solar panel, the batteries etc.
I would probably recommend getting one of the 41hz.com forum users to build the amp and send it to you. We fried ours when testing it, but i think V-Bro build ours perfectly for a small fee.
Hope this helps. You will still have some reading to do in this thread, though
Thank you
I will start looking around and start building it for Roskilde!
Solar panels
Hi,
Saturnus: I'll begin with complimenting you for the excellent design! I plan to build something similar for this years Roskilde.
However I was wondering about the solar panels from Silicon solar that you used in the original design. I tried to order them directly from Silicon solar but was chocked by the shipping cost of 110$!
From where did you order them? Or do you know some equivalent panels available in europe/nordic?
One more thing: do you see any other reason than the reduced forward voltage drop to use a schottky diod instead of a regular with the solar panel connection? Guess it's HF characteristics won't be of any matter at least
Hi,
Saturnus: I'll begin with complimenting you for the excellent design! I plan to build something similar for this years Roskilde.
However I was wondering about the solar panels from Silicon solar that you used in the original design. I tried to order them directly from Silicon solar but was chocked by the shipping cost of 110$!
From where did you order them? Or do you know some equivalent panels available in europe/nordic?
One more thing: do you see any other reason than the reduced forward voltage drop to use a schottky diod instead of a regular with the solar panel connection? Guess it's HF characteristics won't be of any matter at least
jimtegel,
thanks a bunch.
USD 110 in transport? I'm pretty sure I paid USD 140 plus import tax of USD 90 on top.
That's just the price you pay to get something that is guarenteed to survive in space for 20 years
I don't recommend getting them unless ultra-high efficiency and low weight is an absolute priority. You can get a 12V 15W amorphous solar panel with built-in protection diode that match the size of the cabinet exactly for less than SEK 1000 including freight.
I'll see if I can find the link to the Swedish retailer I used last, excellent service there.
thanks a bunch.
USD 110 in transport? I'm pretty sure I paid USD 140 plus import tax of USD 90 on top.
That's just the price you pay to get something that is guarenteed to survive in space for 20 years
I don't recommend getting them unless ultra-high efficiency and low weight is an absolute priority. You can get a 12V 15W amorphous solar panel with built-in protection diode that match the size of the cabinet exactly for less than SEK 1000 including freight.
I'll see if I can find the link to the Swedish retailer I used last, excellent service there.
damping
Oh, I was meaning to ask you another thing:
Do you use any damping material inside the speaker enclosures? Sure, it might make it less loud but theoretically it would improve the frequency response by attenuating the box resonance peaks (and thereby improving the percieved sound quality).
But on the other hand, since the enclosures are so small, the resonances would be in the slightly higher frequency range (~500-700Hz), perhaps making them less noticeable?
Whats your opinion?
Oh, I was meaning to ask you another thing:
Do you use any damping material inside the speaker enclosures? Sure, it might make it less loud but theoretically it would improve the frequency response by attenuating the box resonance peaks (and thereby improving the percieved sound quality).
But on the other hand, since the enclosures are so small, the resonances would be in the slightly higher frequency range (~500-700Hz), perhaps making them less noticeable?
Whats your opinion?
sketchup file?
hi guys,
have been slowly digesting this thread for a number(!) of nights, trying to absorb enough info to be semi confident in giving the design a go myself. although there seems like there is a lot to learn and a lot that i could easily mess up!
there has been mention of a sketchup file for the box design, someone offered to host it i think, but i haven't seen reference to a file anywhere, anyone know where it can be found?
cheers simon
hi guys,
have been slowly digesting this thread for a number(!) of nights, trying to absorb enough info to be semi confident in giving the design a go myself. although there seems like there is a lot to learn and a lot that i could easily mess up!
there has been mention of a sketchup file for the box design, someone offered to host it i think, but i haven't seen reference to a file anywhere, anyone know where it can be found?
cheers simon
hi, another question! i've just read in another thread saturnus saying the position of the boominator relative to the ground will make a diference to the sound quality. On this post saturnus says..
"For the Boominator I use a Q of 1.207 which gives a 3db boost at twice the Fb. This is what I have found sounds the best for outdoor environments provided the speaker is placed directly on the ground."
"Lifting it off the ground on a stand or cart will require an even higher box Q depending on height off the ground and tuning frequency."
I was planning to put it on a bike at about 75cm above the ground, will this make an appreciable difference?
(Hope not - i can't see where to change Qb in WinISD anyway to even begin to take account of it..... )
"For the Boominator I use a Q of 1.207 which gives a 3db boost at twice the Fb. This is what I have found sounds the best for outdoor environments provided the speaker is placed directly on the ground."
"Lifting it off the ground on a stand or cart will require an even higher box Q depending on height off the ground and tuning frequency."
I was planning to put it on a bike at about 75cm above the ground, will this make an appreciable difference?
(Hope not - i can't see where to change Qb in WinISD anyway to even begin to take account of it.....
)
dododoo:
I've built a slightly modified version of Saturnus original design with some extra spacing around the sides of the box enabling me to easily attach a protective grille. Picture here. (not 100% accurate though...)
However, I used 8 pcs. of 12mm 7ply plywood with the following dimensions:
2 end caps: 30x30cm
2 fronts: 27,6 x 87,9cm
2 top/bot. : 30 x 87,9cm
2 inner pcs. 22,1 x 27,6cm
Middle compartment is 10,1cm wide (on battery width =) ). End caps has the bass reflex port of which is 3,6cm deep (3 sheets of plywood), 12cm wide and 3cm tall, rounded at the ends. Hope this helps!
Regarding the Q-value, this is a general factor describing how resonant a system is, easily put. Ideally, the perfect speaker should have a flat frequency response for the perfect sound. However, some humans like bass =), so in order to enhance bass response we can introduce some resonance by create a bass reflex port. And by tuning this port to a certain frequency we "boost" the sensitivity here: higher Q = more boost and narrower frequency band.
As Saturnus write is in the post, the room we're in shapes the sound in the lower frequencies to a large extent by introducing resonances, enhancing bass response at certain frequencies. By playing in the free field, you remove the walls that are creating these resonancies, thus leaving you with a less "bassy" sound. The only reflecting surface you have outdoors is the ground, and by lifting your speaker above ground you slowly remove this surface aswell, thus requiring even higher Q-value to compensate.
This is how I see it, correct me if I'm wrong, I'd appreciate it =)
I've built a slightly modified version of Saturnus original design with some extra spacing around the sides of the box enabling me to easily attach a protective grille. Picture here. (not 100% accurate though...)
However, I used 8 pcs. of 12mm 7ply plywood with the following dimensions:
2 end caps: 30x30cm
2 fronts: 27,6 x 87,9cm
2 top/bot. : 30 x 87,9cm
2 inner pcs. 22,1 x 27,6cm
Middle compartment is 10,1cm wide (on battery width =) ). End caps has the bass reflex port of which is 3,6cm deep (3 sheets of plywood), 12cm wide and 3cm tall, rounded at the ends. Hope this helps!
Regarding the Q-value, this is a general factor describing how resonant a system is, easily put. Ideally, the perfect speaker should have a flat frequency response for the perfect sound. However, some humans like bass =), so in order to enhance bass response we can introduce some resonance by create a bass reflex port. And by tuning this port to a certain frequency we "boost" the sensitivity here: higher Q = more boost and narrower frequency band.
As Saturnus write is in the post, the room we're in shapes the sound in the lower frequencies to a large extent by introducing resonances, enhancing bass response at certain frequencies. By playing in the free field, you remove the walls that are creating these resonancies, thus leaving you with a less "bassy" sound. The only reflecting surface you have outdoors is the ground, and by lifting your speaker above ground you slowly remove this surface aswell, thus requiring even higher Q-value to compensate.
This is how I see it, correct me if I'm wrong, I'd appreciate it =)
thanks for the quick replies - pardon my questions if they seem daft...
i'm planning to put the boominator i make on the back of one of these bikes so i've got a bit more room than average, but weight is definately an issue for the long touring holidays i have planned w/ all the extra camping gear (and the hills).
About Q - does that mean that Q is just a description of how peaky your box design is ? where it peaks still being dependent on the type of driver and the tuning of the box?
My 'problem' is i'd really rather not have to cycle up hills w/ around 14kg of bass drivers on my bike and would rather spend more money on lighter drivers, ( The weight of four 10" neos ( 6kg ) looks like they'll shave off about 8kgs, which is definately worth trying for !
But this then means having to understand how to optimise the box for different thiele small paramters, which i'm having problems getting my head around. WinISD help file made no mention of Qb that i could see! and i'm not entirely sure what the ideal frequency to aim the peak of the db gain curve at is, or for that matter how high to make it ( 3db above 0db? )
So if my legs can't deal w/ the weight of the hp10w's, what frequency should i be aiming to get the peak at?
Or can anyone suggest some other drivers that cost more but weigh less and react similarly to the HP10Ws ?
Jimtegel - thanks for the pic and the measurements, that's made it a lot clearer for me... From your measurements it seems like the internal volume of each of your chambers is around 46 litres minus the drivers, and trying to workout the volume of the hp10w drivers imagining them as a truncated cone ( is that the way to do it? ) i get you internal box volume to be about 46 - ( 2* 4.4 lt ) = 37.2 litres. is that about right?
Just trying to see if i understand enough, i've learnt the hard way doing woodwork that you should always 'measure twice cut once' and in this case I'm finding i've got to first learn how to use the ruler and what it is that i'm actually supposed to be measuring!....
i'm planning to put the boominator i make on the back of one of these bikes so i've got a bit more room than average, but weight is definately an issue for the long touring holidays i have planned w/ all the extra camping gear (and the hills).
About Q - does that mean that Q is just a description of how peaky your box design is ? where it peaks still being dependent on the type of driver and the tuning of the box?
My 'problem' is i'd really rather not have to cycle up hills w/ around 14kg of bass drivers on my bike and would rather spend more money on lighter drivers, ( The weight of four 10" neos ( 6kg ) looks like they'll shave off about 8kgs, which is definately worth trying for !
But this then means having to understand how to optimise the box for different thiele small paramters, which i'm having problems getting my head around. WinISD help file made no mention of Qb that i could see! and i'm not entirely sure what the ideal frequency to aim the peak of the db gain curve at is, or for that matter how high to make it ( 3db above 0db? )
So if my legs can't deal w/ the weight of the hp10w's, what frequency should i be aiming to get the peak at?
Or can anyone suggest some other drivers that cost more but weigh less and react similarly to the HP10Ws ?
Jimtegel - thanks for the pic and the measurements, that's made it a lot clearer for me... From your measurements it seems like the internal volume of each of your chambers is around 46 litres minus the drivers, and trying to workout the volume of the hp10w drivers imagining them as a truncated cone ( is that the way to do it? ) i get you internal box volume to be about 46 - ( 2* 4.4 lt ) = 37.2 litres. is that about right?
Just trying to see if i understand enough, i've learnt the hard way doing woodwork that you should always 'measure twice cut once' and in this case I'm finding i've got to first learn how to use the ruler and what it is that i'm actually supposed to be measuring!....
From this thread I read out that the boominator enclosure volume was supposed to be about 2 x 23L, I did not compensate for the driver volumes... maybe that was a mistake
If you need a lighter system, maybe you should use smaller/lighter drivers? I've built some stuff with these drivers once: Visaton BG17. They are light (6.5", around 700g) fairly sensitive (93dB) and very cheap! I've searched pretty much everywhere for low weight/high sensitivity drivers but there's really nothing like the HP-10W:s.
Another way to save weight is to choose the right plywood. From what I know, the lightest is from coniferous tree (not sure if thats the right english translation), such as spruce.
As Saturnus has mentioned, it's a waste of energy playing anything under 100Hz in the open field, so putting your -3dB point around this frequency should be a good starting point. Also you might wan't to create a peak in the bass register, like this. Try it in WinISD, and you should probably get a pretty decent sounding box (of course sound "quality" is also dependent on the frequency response of the driver)
About the Q again: I was just trying to describe my comprehension about Q-factor, (which might be wrong). But yeah, it's pretty much about how "peaky" or resonant your system is, and yes: it depends much on the T/S parameters on the driver and box tuning.
If you need a lighter system, maybe you should use smaller/lighter drivers? I've built some stuff with these drivers once: Visaton BG17. They are light (6.5", around 700g) fairly sensitive (93dB) and very cheap! I've searched pretty much everywhere for low weight/high sensitivity drivers but there's really nothing like the HP-10W:s.
Another way to save weight is to choose the right plywood. From what I know, the lightest is from coniferous tree (not sure if thats the right english translation
), such as spruce.As Saturnus has mentioned, it's a waste of energy playing anything under 100Hz in the open field, so putting your -3dB point around this frequency should be a good starting point. Also you might wan't to create a peak in the bass register, like this. Try it in WinISD, and you should probably get a pretty decent sounding box (of course sound "quality" is also dependent on the frequency response of the driver)
About the Q again: I was just trying to describe my comprehension about Q-factor, (which might be wrong). But yeah, it's pretty much about how "peaky" or resonant your system is, and yes: it depends much on the T/S parameters on the driver and box tuning.