For simplicity you can consider the room boost an inverse 1st order filter at roughly 120Hz for semi-free field use as we're talking about here. So it's +3dB at 120Hz, +6db at 60Hz, +12dB at 30Hz and +15dB at 20Hz. So yes, it needs 4 times the output to compensate for the loss of the +6dB boost at roughly 60Hz. Please note that the boost actually starts at roughly 200Hz (120Hz*Pi/2).
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Yes, but it would be more difficult to implement. If high quality neo drivers are wanted then speakers such as P.audio SN10MB are perfect drop in replacements for the P.audio HP10Ws. They're not lighter though, actually they weigh slightly more, but they're better quality with twice as good sensitivity (+3dB) over the HP10W. They also cost about 5 times more a piece though.
Saulty, I'm also planning to design a monophonic boombox with a cabinet dimension similar to yours, and I'm wondering if you still think the CTS/Motorola piezo tweeter is efficient enough to keep up with the Fatality driver you employed. How is the fidelity, and did you find it could cross over as low as 1.5k without issue? Basically, if you had to do it all over again, could you recommend said tweeter for the application?
Also, may I ask why you went for the far more expensive Class D Audio board over Hifimediy's, T3 1.0 tk2050/bt1597 Tripath board? I know that requires a 48v power source for maximum output, but in all other parameters, it does seem ideal.
Ps... I'd settled on the speaker drivers before I saw this thread. Either coincidence, or a clue that they've got the best parameters for the application - at least at a moderate price point.
Also, may I ask why you went for the far more expensive Class D Audio board over Hifimediy's, T3 1.0 tk2050/bt1597 Tripath board? I know that requires a 48v power source for maximum output, but in all other parameters, it does seem ideal.
Ps... I'd settled on the speaker drivers before I saw this thread. Either coincidence, or a clue that they've got the best parameters for the application - at least at a moderate price point.
Yes. The CTR KSN1001A, the -01A one because it's extremely easy to integrate as all it takes is a 76 diameter cut-out and some glue on the back to flushmount it.. Still tinkering with it to get it sounding right.
Alternatively you can try some of the many many replicas/replacements of the same, or the -05A version, but I've yet to find any that has more than just acceptable sound quality. Also note that most of the replicas/replacements don't match the 94dB/w/m sensitivity of the original CTS one.
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http://www.ljudia.no/hyttalerelementer-s82124/piezo-c78561/qlm-1005-p78564/"]http://www.ljudia.no/hyttalerelementer-s82124/piezo-c78561/qlm-1005-p78564/
Bad link but I figured out what it was anyways. Run of the mill replica of the KSN1005A. Not one of the worst around but I'd only recommend the originals unless someone can send me a replica of the KSN1001A that actually sounds acceptable.
Hi.
Could you bother to tell me witch speakers and amp you would choose if you didnt need battery suply? I will mostly use it in a Volleball arena and at work building houses.
How could i conect a mic and volume controll for it (the mic that is).
Prisiate your help. I have tried to find a deasent boombox to by, but i dont think
it exist.
Bjoern
Well, after much experimenting I keep coming back to the conclusion that the current design is basically perfect in every way. There's only one minor change and a few refined details.
The minor change is that the handle/port is now replaced with a plastic slot handle where the end is cut off so that it duplicates as a port just as in the original design but just a lot more easy to make. You can even vary the length to fit tuning demands.
Boominator mark.II recommended parts:
Woofers: P.audio HP10W (no alternatives)
Tweeters: CTR KSN1001A (or replicas)
Amplifier: 41Hz Amp6basic (or other TA2020/TA2021 based amp)
Batteries: up to 3 12V 7Ah SLAs in parallel internally (or Li-ion pack fitting in size)
Boominator Signature recommended parts:
Woofers: P.audio SN10MB series II (no alternatives)
Tweeters: P.audio PHT407N (or similar high dispersion, high sensitivity and high quality tweeter horn)
Amplifier: 41Hz Amp9basic (or other 4 channel Tripath based amp)
Filtering: active at 2.4KHz with passive correction (or mix PLLXO and passive filters)
Batteries: up to 3 12.8V 6.8Ah LFP packs (no viable alternatives to the LFP pack, they're superior in every way to any other battery type)
Both versions can solar panel integrated or loose on top if so desired. I recommend a standard cheap 15W "12V" amorphous panel where the casing is stripped off for integration.
For 24V or higher operation on the Signature (or if you have another amp on the mark II), I recommend switching to an external power supply and not use the internal batteries.
You can naturally mix and match as you like, and even use alternatives I haven't listed but I can't guarentee as good a result if you do.
The minor change is that the handle/port is now replaced with a plastic slot handle where the end is cut off so that it duplicates as a port just as in the original design but just a lot more easy to make. You can even vary the length to fit tuning demands.
Boominator mark.II recommended parts:
Woofers: P.audio HP10W (no alternatives)
Tweeters: CTR KSN1001A (or replicas)
Amplifier: 41Hz Amp6basic (or other TA2020/TA2021 based amp)
Batteries: up to 3 12V 7Ah SLAs in parallel internally (or Li-ion pack fitting in size)
Boominator Signature recommended parts:
Woofers: P.audio SN10MB series II (no alternatives)
Tweeters: P.audio PHT407N (or similar high dispersion, high sensitivity and high quality tweeter horn)
Amplifier: 41Hz Amp9basic (or other 4 channel Tripath based amp)
Filtering: active at 2.4KHz with passive correction (or mix PLLXO and passive filters)
Batteries: up to 3 12.8V 6.8Ah LFP packs (no viable alternatives to the LFP pack, they're superior in every way to any other battery type)
Both versions can solar panel integrated or loose on top if so desired. I recommend a standard cheap 15W "12V" amorphous panel where the casing is stripped off for integration.
For 24V or higher operation on the Signature (or if you have another amp on the mark II), I recommend switching to an external power supply and not use the internal batteries.
You can naturally mix and match as you like, and even use alternatives I haven't listed but I can't guarentee as good a result if you do.
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Find the new SketchUp drawing here. Please note that all I ask anyone using this design or anything that could concieabley be considered derivative of this design is that:
a) it's for non-commercial use only. You're not allowed to make and sell any for profit beyond a reasonable compensation for manual labour. If in doubt, ask first.
b) That you post pictures of your build either here directly or you place a link to photos of your build here.
That's all.
Now on to make the Signature edition.
a) it's for non-commercial use only. You're not allowed to make and sell any for profit beyond a reasonable compensation for manual labour. If in doubt, ask first.
b) That you post pictures of your build either here directly or you place a link to photos of your build here.
That's all.
Now on to make the Signature edition.
I haven't spent enough time listening to it to say for sure. If anything, it may be 1-2db off on the high end but I'd need to add a second one to produce a +3db gain to see if it is really any better. I can say that when I paired them with the 10" goldwood woofers rated at 93 or 94, I did get some comments about those damn horns hurting people's ears. Probably the overall volume they were complaining about though. They may have been a little bright paired with 93db woofers. Also keep in mind that their frequency response isn't perfectly flat at 92db. http://piezosource.com/general/datasheets/Piezo_1141_datasheet.pdf
It moves from 90-99 depending on frequency. Some people are applying a resistor to taper some of that peak that is noticed up in the 8khz range.
I don't think I'm going to make any more changes until I get some serious hours of listening with it. If I'm unhappy, I may apply the resistor and add a second one.
I went with the class D over the tripath purely for the extra headroom. In 99% of situations, I won't push more than 75W through it and a 2050 would be perfect. The Class D board with TI chip gives me a clean doubling of that before any real distortion for the 1% of times when I want the last 3db out of the system. That said, to save a good chunk of money, I'd suggest going the sure 2050 route with upgraded caps. $100 less and you can get away with 2 12V batteries vs. 3 saving a few more bucks. And 24v chargers seem to be a dime a dozen with all the electric scooters out there so you save a bit on the charger. I'd suggest taking the savings and building yourself a nice battery pack like the one Saturnus suggests below and shave off a few lbs.
I spent some time listening and did some side by side comparisons against my version 1 build. The highs were definitely lacking. Everything seemed a bit cloudy compared to V1. So I pulled one of the piezo's from my original build and added it to the new build. Which should give the 1.8khz and up another 3db. The frequency response via iphone RTA came up a bit, but the actual sound improved remarkably. 3db at that frequency range is apparently very noticeable to the ear. That woofer really was too sensitive for the single piezo. Now it is a very nice balance.
i know the charger concerns have been discussed in this thread before, but i am still a little confused on the solutions available. I a have been looking at this
Mobil Solcelle sæt 13W - Bestil hos BilligCamping.dk
At the moment i got 2 12V, 7.2ah SLA batteries in parallell. Furthermore i have one of these
NEW Class T Amp TA2024 Amplifier Tripath Chip TA 2024 on eBay (end time 23-Dec-10 19:21:19 GMT)
according to the specs the input voltage should be between 12V-13.25V on the amp.. i Saw that saturnus said something about adding an extra 10% to that number. Does this manoeuvre apply to amps in general or just the amp6b?
The 13W solar panel charges the battery with 17.5V max and in this case i woldn't be capable of connecting the panel directly to the battery and the battery directly to the amp?
With the setup above what would you guys recommend..? Plug the panel directly to the battery and the battery directly to the amp, or is there any smarter and more safe solution?
Mobil Solcelle sæt 13W - Bestil hos BilligCamping.dk
At the moment i got 2 12V, 7.2ah SLA batteries in parallell. Furthermore i have one of these
NEW Class T Amp TA2024 Amplifier Tripath Chip TA 2024 on eBay (end time 23-Dec-10 19:21:19 GMT)
according to the specs the input voltage should be between 12V-13.25V on the amp.. i Saw that saturnus said something about adding an extra 10% to that number. Does this manoeuvre apply to amps in general or just the amp6b?
The 13W solar panel charges the battery with 17.5V max and in this case i woldn't be capable of connecting the panel directly to the battery and the battery directly to the amp?
With the setup above what would you guys recommend..? Plug the panel directly to the battery and the battery directly to the amp, or is there any smarter and more safe solution?
Exactly. The internal impeance in the batteries will make sure that the voltage never exceeds a safe voltage for the amp. But you should never connect the amp directly to the solar panels.
as always, thank you for the answer.. But to clearify this for me.. Will i then need a charger if i want the amp and then solar panel running at the same time or will it be alright if i couple it like this? (making a direct connection between the panel and the amp but with the battery in parrallel)
An externally hosted image should be here but it was not working when we last tested it.
Hi Saturnus,
I currently run a similar boombox to yours, but i need to upgrade it as im not yet happy with it
i currently run on bass two of these
Beyma Speakers - Beyma 8BR40 8" speaker - Beyma 8BR40 100 watt 8" woofer for all hi-fi and studio monitor bass speakers. Beyma 8BR40 and other Beyma 8" speakers here.
with a sure 2*100 off a 24v SLA supply
however, i like bass. this is not enough bass. (music is mainly DNB / dubstep).
the rest of the setup is 2 more sure boards running two 6" mids and two APT80s (triamped off active Xover)
how would two of these run off an AMP-9 fare? or can you suggest another UK friendly bass sensitive (hitting 60-70 would be great) driver? ta!
http://www.fane-international.com/downloads/Fane_Sovereign_10300.pdf
edit: or perhaps if i ran those 10's up to piezos with a single amp9? that would (MASSIVELY) improve battery life .. but SPL? hmmmmmmm
I currently run a similar boombox to yours, but i need to upgrade it as im not yet happy with it
i currently run on bass two of these
Beyma Speakers - Beyma 8BR40 8" speaker - Beyma 8BR40 100 watt 8" woofer for all hi-fi and studio monitor bass speakers. Beyma 8BR40 and other Beyma 8" speakers here.
with a sure 2*100 off a 24v SLA supply
however, i like bass. this is not enough bass.
(music is mainly DNB / dubstep). the rest of the setup is 2 more sure boards running two 6" mids and two APT80s (triamped off active Xover)
how would two of these run off an AMP-9 fare? or can you suggest another UK friendly bass sensitive (hitting 60-70 would be great) driver? ta!
http://www.fane-international.com/downloads/Fane_Sovereign_10300.pdf
edit: or perhaps if i ran those 10's up to piezos with a single amp9? that would (MASSIVELY) improve battery life .. but SPL? hmmmmmmm
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Why not get the HP10Ws I use. It's practically the only drivers in it's price range I can recommend. You can order them from any of the many European resellers since there's currently no UK reseller (as far as I know). It'll be about £80 including delivery for a pair.
An amp9basic will not put out more power as output power is determined by the laws of physics, ie. the supply voltage and load impendance, and since neither change, the output power won't change either. But you would have one 4 channel amp to drive the woofers and I'd recommend an active crossover or PLLXO crossing to a suitable horn directly on the other 2 channels.
Just going to the 10" woofers, either the HP10W or the one you link to, will give you about 4 times more output, ie. +6dB, just because they're that more sensitive.
An amp9basic will not put out more power as output power is determined by the laws of physics, ie. the supply voltage and load impendance, and since neither change, the output power won't change either. But you would have one 4 channel amp to drive the woofers and I'd recommend an active crossover or PLLXO crossing to a suitable horn directly on the other 2 channels.
Just going to the 10" woofers, either the HP10W or the one you link to, will give you about 4 times more output, ie. +6dB, just because they're that more sensitive.
great, ill start hunting down some euro sellers
you mention the amp power being limited by the the laws of physics - but this class D amplifier Class D Audio TI-300 Amplifier - PRODUCTS
(another candidate, as mentioned earlier on in the thread - further up the page) puts out more power than the amp9, i take it pushes the voltage rails higher than Vsupply for the amp?
so, with this amplifier [or the bigger brother], 107db 1w1m high [two apt80s], and 98db 1w1m lowmid [two 10"s] should be a potent combo by my calculations
