HiWave HiBM65C20F 3-1/2" BMR Wide Range Driver Measurements and Impressions - Page 3 - diyAudio
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Old 28th December 2012, 10:33 PM   #21
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Er... Balanced mode not bending lol!
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Old 29th December 2012, 05:51 PM   #22
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Fleawatt Perdomo Cigar Box Desktop Speakers - YouTube


And for $20, you can make a pair of cigar box desktop speakers with them.
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Old 31st December 2012, 12:10 PM   #23
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Default Copied post from other BMR thread

Happy new year ( 's Eve!)

I am getting great results with line array's using 8, 12, or 16 drivers per channel using the 4.5 inch BMR.
Here are a few important points that took me a while to fully appreciate:

(1) DSP / Eq is a must. There is no way passive Eq / crossovers / notches etc can do it without hideous complexity, cost, size, and loss of efficiency.

As a minimum try the Eq in JRiver media (or similar VST host), or even better Blue Cat Audio or similar studio grade plugins, Blue Cat do great free plugins to start you off. Reaper, Fab Filter etc are all great to.

(2) For full range music with av / peak SPL's at around 85dB to 105dB, size matters...The Sd of the 4.5 inch is 60cm square, a typical 12 inch driver has an Sd of around 550 cm square...Eight 4.5 inch BMR's = 480 cm square, 12 BMR's = 720 and 16 BMR,s = 960 cm square.

(3) All my designs are "on wall" and use curved cabinets which curve back to meet the wall, this almost eliminates the baffle step issue. Plus it gives you "free" low and low / mid frequency boost. I have measured solid bass ( +- 4dB) down to the high 30Hz low 40Hz depending on Eq and number of drivers. It sounds even deeper than it mearures...!

(4) Comb Filtering is a non issue. Yes you read that right! In real rooms ( not anechoic chambers ) and on wall location, the 4.5 inch BMR line arrays simply flood the entire space with seamless low distortion music. They are dynamic, detailed and so supple & liquid its delightful and astonishing in equal measure.

(5) The smaller BMR's just do not have the ability ( Sd and power handling) to generate the SPL's and dynamics. You have to push them so hard they sound ragged and stressed.
Also the big ferrite magnets really obstruct the back wave and muddy the midrange. The Neo magnet versions are way better in this respect, so pure and natural, but they are way more expensive...

Hope the above helps.
All the best
Derek.
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Old 9th March 2013, 07:09 PM   #24
SimontY is offline SimontY  United Kingdom
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Hi guys,

Sorry to dredge a thread up from the dead but I was searching for a 3.5" driver to use in my car... The dash speakers are 3.5" in diameter and the car audio market offerings seem a little underwhelming and it's very hard to find reviews of almost any of them. I widened my search to full range drivers and came across this. Given an inline cap for hi-pass filtering, could these sound good (relative to the low cost!) in a car environment? They'd be bolstered beneath by larger door speakers and, later, a sub.

I realise they'd not want to play very loud due to the high impedance, lack of amplifier power (from a car HU) and being so small, but relieved of bass could they sound nice?

Thanks,
Simon
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Old 10th March 2013, 06:26 AM   #25
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Yeah they sound alright. Although they are designed for very wide dispersion. Depending on the location that may not go well.

-Matt

Edit: Overkill brings up a good point that the large magnet really mucks things up. But in car audio it might not be as noticeable.

I would go check out these Vifa's
http://www.parts-express.com/pe/show...umber=264-1062

Last edited by mattlong8; 10th March 2013 at 06:29 AM.
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Old 10th March 2013, 01:09 PM   #26
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Default Car or Beach?

Hey Simon,

I suppose at the price you cant really go wrong for in car use.

Worst case if they sound really bad you can take em out the car and make a cool boom box for the beach!

Try a rectangular Ply wood box with an 8mm alloy back plate (heatsink for power amps and anchor for battery) approx 35 litres with 16 individual 1.5 litre chambers for the drivers in a 4 by 4 layout, and the rest of the internal volume for the power amp and battery.

Wire up the 12 BMR's as 4 groups of 1 Ohm for a 4 Ohm total load.
The 16 drivers will give you a thoretical 12 dB gain in sensitivity ( nearer 10.5 dB in reality), include decent class D power amp and a typical 5 to 6 Kg Lipo battery and you will have a genuine full range, 100 dB to 105dB SPL for beach and Bar BQ's...

You could go all the way and turn it into a " Beach Server "....Include a low cost low power DSP / mother board and load it up with Jriver & Jplay, this allows free access to the rather handy DSP / Eq, add a 250 Gb SSD drive for music and the LiPo battery will power it all 14 to 18 hours in between charges....

Party on Garth!!
Cheers
Derek.
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Old 10th March 2013, 01:29 PM   #27
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The Vifa looks very nice indeed, just need to find somewhere in the UK that stocks it. I have a feeling it would be the better choice of the two, and very affordable (in the US at least).

Derek - the boombox sounds amazing, someone should make that!

Simon
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Old 10th March 2013, 03:32 PM   #28
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Default BMR Boom Box

Hi Simon,

I hope some one tries it before the summer, if not I will go for it...In August we are taking the kids to Devon for a beach and camping holiday, it would be fab to have some portable music that actually sounds " turn it up " good rather than the usual boom box " turn that noise down" !

Cheers
Derek.
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Old 10th March 2013, 06:46 PM   #29
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Just ordered 4 of the 65mm square ones, from RS.

The plan is to make a tiny Boominator. With the bipole configuration and wide dispersion, this should give near-perfect 360 dispersion.

I'm not expecting huge SPLs, but should sound half-decent at lower levels.
I did think about trying the high aspect ratio BMRs, or maybe the smaller square ones, but the 65mm square and big round ones are the only ones to give half-decent frequency response.

I have a 2x10w (@8ohm - the 4ohm drivers will be wired in series) class D amplifier that'll run on 5-15v, so I'm thinking of running off 8x AA batteries. That way, I can take spare batteries, instead of a "once its dead, its dead" set-up.

I'll start a new thread once things get going.

Chris
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Old 10th March 2013, 09:31 PM   #30
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Default Baby Boomer!

Hi Chris,

Nice idea, I think it will be a really cool little box and it will punch well above its weight.

Using any tiny Sd driver in a small open baffle, you are going to struggle to get anything below 100Hz, but what you do get will sound natural and fill the room / car / tent (!) with pleasant sounds.

Not that it matters for a boom box or boom baffle" but the large ferrite rear magnet / does reflect a great deal the rear wave straight back through the cone.

On the up side if the cone is the same or similar to the 4.5 inch Neo driver, its a double thickness honeycomb cone and much less sonically transparent than a typical small featherweight cone found in most small full range drivers.

All the best
Derek.
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