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Building new battery powered speaker

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Category: General
Forum Name: 12v Powered Systems
Forum Description: From Mini-rigs to ICE, all your low voltage audio needs here...
Printed Date: 25 May 2022 at 2:46am
Software Version: Web Wiz Forums 12.05 -

Topic: Building new battery powered speaker
Posted By: eshroom
Subject: Building new battery powered speaker
Date Posted: 26 August 2020 at 8:50am
I've just finished building a halfinator and want to move onto something new.

The halfinator uses a tpa3116 mono board with hp10 and hp207 paralleled with passive crossover. It has an 18,000mah 19.6v lifepo4 battery powering it. Its a great speaker.

The new speaker I want to be one directional rather than back to back, which I only need occasionally. I'm also looking for a better amp solution. Currently the mono board does not have built in Bluetooth and it does not have enough gain - I can only get higher volume levels by including a preamp. As a result with added Bluetooth board and preamp there are three items draining the battery instead of just the amp.

Can someone recommend a highly efficient amp that will solve these issues, so with Bluetooth and a decent preamp or higher gain built in? My understanding is that only a mono amp will do as stereo class d amps can't simply be bridged to mono and in order to get the volume at low voltage I need to keep impedence at 4ohms.

Worst case some amp modding is possible in order to achieve what I need.

As for drivers, the hp10's are good, but I want to move to a 3 driver setup. Either three 10 inch drivers, or 2 10's and a tweeter. Any thoughts on extremely efficient drivers I can use for the set up. Battery life is key.

I want to conserve battery as much as possible, so crossover and baffle step correction must be passive.

Thanks for any ideas!

Posted By: slaz
Date Posted: 26 August 2020 at 2:19pm
Originally posted by eshroom eshroom wrote:

2 10's and a tweeter.

well the above in non-bipolar format is -  errm .... pretty much what Johnny Engberg (aka Saturnus, the designer of the boominator) came up with - the Soundboks.

But his design uses 3 amp channels and a DSP of some sort. Designing, building, and testing a custom passive Xover is not for the faint of heart. I'll be surprised if you can find a off-the-shelf passive Xover for 4R bass/mid with a 8R tweeter - and a very specifc Xover point and specific padding and slopes etc.


Posted By: mobiele eenheid
Date Posted: 26 August 2020 at 2:52pm
Quote I want to conserve battery as much as possible, so crossover and baffle step correction must be passive
I suppose you mean active?

Passive filters burn away about half the power they receive. Plus active filters often allow a steep high pass, for the Boominator that would probably be 24 dB/ octave at 50 Hz or higher. It the signal isn't clean or contains a lot of low frequencies output we're talking about 3 - 6 dB difference here.

I've used a booster myself in the past, nowadays I'm looking at higher voltage battery packs.

Posted By: eshroom
Date Posted: 26 August 2020 at 6:27pm
Hmmm. As you can tell, despite reading about this, planning and executing for the past year, I am still very much a novice.

If it actually improves efficiency then active crossover/DSP it is.

I believe Soundboks uses a 12v 7ah battery, which can switch up to 24v. Incredible how much life those speakers have on that much power. I'd be looking to use the same 19.6v 18ah battery I've got, despite weight. To compensate I'd be looking to make the cabinet out of fibreglass or carbon fibre - I have experience in working with those materials, but have no idea about their acoustic qualities compared to wood. They are very hard materials, so I hope good.

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