Compact 2 way fullrange cabinet |
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Monkeys
Registered User Joined: 30 August 2012 Location: Melbourne - Aus Status: Offline Points: 429 |
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Ok, I have a lot to think about if I'm going to consider passive radiators.
Before I do that, what are peoples thoughts on this driver from Volt, the BM 165.1 I've read a lot of good things about these small Volt drivers. This one us supposedly able to produce down to 40hz in a 20l ported enclosure. Thoughts?
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APW
Young Croc Joined: 13 November 2012 Location: Kent, UK Status: Offline Points: 1174 |
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I have never used this particular driver however I can tell you that with a sensitivity of 88db/W 50watts gives you an output of 105db at one meter… without allowing for losses, to get your required 110db you would need to feed it 200watts, the driver is rated 100watts AES!! With battery systems efficiency is everything. |
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Monkeys
Registered User Joined: 30 August 2012 Location: Melbourne - Aus Status: Offline Points: 429 |
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Yeah, I'd kind of accepted that I might need to compromise loudness. I don't mind too much if its not thumping loud. 105db at 1m is still loud enough to keep a room full of people pretty happy, no?
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APW
Young Croc Joined: 13 November 2012 Location: Kent, UK Status: Offline Points: 1174 |
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I doubt it.... If 1 mtr = 105db, then: 2 mtrs = 99db 3 mtrs = 95.4db 4 mtrs = 92db 5mtrs = 91db in the real world you
will be ragging every last ounce out of the driver so you will also have power compression to deal with, you can probably knock another 3 to 5db off those figures.
Edited by APW - 31 January 2020 at 10:55am |
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Monkeys
Registered User Joined: 30 August 2012 Location: Melbourne - Aus Status: Offline Points: 429 |
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Hmmm, in that case I might need to reconsider my approach.
What about the 8", the 220.1: https://voltloudspeakers.co.uk/loudspeakers/bm2201-8/ It's got an extra 3db efficiency, which isn't a great deal but it's still gonna save half the power required. It appears to be a non-coaxial version of the CX220.1 which is apparently amazing in a 20L box, or so I read on here? |
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APW
Young Croc Joined: 13 November 2012 Location: Kent, UK Status: Offline Points: 1174 |
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When placing the BM220.1 in a 20ltr box tuned at about 50hz (50hz gave the best results with 20Ltrs): Yes you get you an f3 of about 45Hz when looking at just the data below about 150Hz, however you have already lost 3db when compared to the baseline data above 150Hz so you are back to a sensitivity of 88db/w below 150Hz!! Like has already been suggested: Download & install WisISD, then enter the data from the spec sheet for any drivers you are interested in (the driver may be already in the database) then try different box sizes and tuning, this will give you some idea if a driver is going to be any good for your needs. Edited by APW - 31 January 2020 at 12:18pm |
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JonB67
Young Croc Joined: 22 April 2016 Location: UK Status: Offline Points: 1376 |
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If you want an 8 inch driver, take a look at the fane 8-225. Cheap enough to take a punt on, great reputation and better efficiency than what youre looking at.
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MarjanM
Old Croc Joined: 10 February 2005 Location: Macedonia Status: Offline Points: 7816 |
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It wont do 50Hz.
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Marjan Milosevic
MM-Acoustics www.mm-acoustics.com https://www.facebook.com/pages/MM-Acoustics/608901282527713 |
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smitske96
Young Croc Joined: 16 February 2016 Location: The Netherlands Status: Offline Points: 1092 |
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It will do 50 Hz, just not loud enough But Marjan is right, if you want something happening down low, 12" would be the minimum for me.
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Monkeys
Registered User Joined: 30 August 2012 Location: Melbourne - Aus Status: Offline Points: 429 |
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12" would be too big. I want to keep the box size below 30l. Goddamn physics! I'll have to compromise further somewhere in the design, I can't decide wheter to sacrifice low end, or efficiency (and as a result, loudness). To elaborate further on what I'm aiming for, the unit would operate primarily as a battery powered Bluetooth speaker (looking at getting a pair of Lutkevelds boards). I'd like it to produce a high quality relatively full range sound at low-moderate volumes, that would be it's use day to day. But with the option to operate as a compact PA speaker, at which times efficiency on battery power could become non-essential since I could arrange to bring additional batteries to power it for longer periods.. Hmmm. Getting WinISD as we speaker =)
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studio45
Old Croc Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3864 |
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You have to sacrifice low end and box smallness for 12v use, because efficiency is KING. There's no point building a rig that needs so many batteries to play all day, and such big heavy amps, that you can't take it anywhere without a big van. You might as well build a 240v rig and buy a generator.
If that really worries you, you can always build a separately powered subwoofer system and bring it out when necessary. But that will *not* be every party.
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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
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Xoc1
Registered User Joined: 15 October 2012 Location: Devon UK Status: Offline Points: 397 |
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When you Say Box size 30L are you talking External volume or internal Volume - Box minus walls drivers. ports etc? The Lutkevelds boards are Class D but do not have DC DC converters so will not do anything like 50w More like 7 watts RMS on a 12volt battery into a 8 ohm speaker. or 15w in to a 4 ohm driver |
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