Speakerplans.com Homepage
Forum Home Forum Home > General > 12v Powered Systems
  New Posts New Posts RSS Feed - Compact 2 way fullrange cabinet
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Compact 2 way fullrange cabinet

 Post Reply Post Reply Page  123 4>
Author
Message
Monkeys View Drop Down
Registered User
Registered User


Joined: 30 August 2012
Location: Melbourne - Aus
Status: Offline
Points: 429
Post Options Post Options   Thanks (0) Thanks(0)   Quote Monkeys Quote  Post ReplyReply Direct Link To This Post Topic: Compact 2 way fullrange cabinet
    Posted: 28 January 2020 at 4:53am
This might be ambitious, but I'm looking in to building a fairly compact high efficiency 2-way "full-range" cabinet for use in a 12v rig. Minimal size, weight and maximum efficiency are the key restraints for this build (and obviously sound good too, preferably). Trying to keep the build below around 12kg total weight, so fairly small without too much wood and bracing etc is what I'm after.

Ideally the unit will produce bass from around 40-50hz with some level of efficiency, and meet a 1" compression driver at around 2500hz.

The driver I'm looking at for the bass/mids is this. Open to suggestions for other drivers though. This is a 10" but there's also an 8" which looks decent as well, although the efficiency is much lower.

https://voltloudspeakers.co.uk/loudspeakers/bm2514-10/

From what I can ascertain, the only way to get the bass/mid unit to produce from 40-50hz up to 2500 to meet a 1" compression driver is in a reflex box. A small horn would add some efficiency but sound terrible about about 500hz, right?

What about a ported box? Would that be better vs a sealed box in terms of bass response, while still providing good sound up to 2.5khz?


Back to Top
MarjanM View Drop Down
Old Croc
Old Croc
Avatar

Joined: 10 February 2005
Location: Macedonia
Status: Offline
Points: 7404
Post Options Post Options   Thanks (0) Thanks(0)   Quote MarjanM Quote  Post ReplyReply Direct Link To This Post Posted: 28 January 2020 at 1:29pm
Reflex box IS a PORTED box. Yes it will add to the low end efficiency considerably compared to a closed box.
40-50hz out of a 10 inch driver means low efficiency.
That Volt driver has resonating frequency of 59hz and you should not tune the box below that point if you plan to push the stated power handling. 
If you must have 40-50Hz look for a 8 or 10 inch driver with rubber surround. Those are usually at 90-93db efficiency.
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713
Back to Top
studio45 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 16 October 2007
Location: United Kingdom
Status: Offline
Points: 3629
Post Options Post Options   Thanks (0) Thanks(0)   Quote studio45 Quote  Post ReplyReply Direct Link To This Post Posted: 28 January 2020 at 3:04pm
Yes I agree your low end target there is a bit much to expect from a 10" driver, with any authority. Remember kick drum hits at about 63Hz and unless you're playing deep dark heavy dub all the time, frequencies below 60Hz are pretty much optional, and in the context of 12v there's a strong case to consider them a total waste of battery power. 
Aim for "boom" rather than "thud" as a bass voicing and you'll have much more success ;)
Studio45 - Box Builder Commotion Soundsystem -Mobile PA
Back to Top
JonB67 View Drop Down
Young Croc
Young Croc


Joined: 22 April 2016
Location: UK
Status: Offline
Points: 1026
Post Options Post Options   Thanks (0) Thanks(0)   Quote JonB67 Quote  Post ReplyReply Direct Link To This Post Posted: 28 January 2020 at 4:33pm
Take a look at the available coaxial drivers. They will produce a nice compact box, some have passive crossovers designed for them to make the process easy. 

You'll have to trade efficiency vs extention. Do you want it loud or low? I think if you sim it you'll find the loss in spl (output volume) isnt worth the gain in frequency. 

If you need some sub, build a small efficient sub like a tapped horn (tham or ss15 ) with an efficient driver. 
Back to Top
Xoc1 View Drop Down
Registered User
Registered User


Joined: 15 October 2012
Location: Devon UK
Status: Offline
Points: 230
Post Options Post Options   Thanks (0) Thanks(0)   Quote Xoc1 Quote  Post ReplyReply Direct Link To This Post Posted: 28 January 2020 at 8:49pm
I think if you want efficient & low you will need a separate sub driver/ cabinet.

The Volt BM251.4 - 10"has an xmax of 2.5mm (and a quick search showed it as unavailable)
So its never going to shift much air. There are some 12 drivers from B&C for instance that have good efficiency and a bigger x-max allowing them to go a bit lower.
To get an idea of how they might perform you might try a sim in a sealed box to see how the bass rolls off . Often for a sealed midrange a smaller box will give a steeper bass roll off with more efficient midrange where you need it.
Next step would be to try adding a port, This can be used to extend the bass of the mid driver without over-excursion but probably would end up being tuned higher than your target frequency, and needing a high pass filter, to attain any real efficiency. Hence the need for a separate bass driver.
The other alternative is to give up on the ideas of loud to get low & small.
A SS15 tapped horn might give you 103 db/w
A Tham might give you 100 db/w
A big reflex cab might give you 96 db/w
Most domestic sized speakers that go low might give you 86 db/w
OMG my Daughter has gone prog rock!
http://www.strangeredearth.com/videos/
Back to Top
Monkeys View Drop Down
Registered User
Registered User


Joined: 30 August 2012
Location: Melbourne - Aus
Status: Offline
Points: 429
Post Options Post Options   Thanks (0) Thanks(0)   Quote Monkeys Quote  Post ReplyReply Direct Link To This Post Posted: 28 January 2020 at 9:58pm
Thanks for all the input everyone.

I should add that another key constraint of the project is that it doesn't need to be super loud, around 110-115db would be quite sufficient to conserve battery power (and operate within xmax) and I plan to implement a limit at that.

So with that in mind, is there a driver you could reccommend for a reflex box which will be able to go fairly low (even 50hz?) with some semi decent efficiency? Ideally the bass driver should be able to get to 110db at around 50w?
Back to Top
Xoc1 View Drop Down
Registered User
Registered User


Joined: 15 October 2012
Location: Devon UK
Status: Offline
Points: 230
Post Options Post Options   Thanks (0) Thanks(0)   Quote Xoc1 Quote  Post ReplyReply Direct Link To This Post Posted: 29 January 2020 at 1:27pm
50 watts is 17 dbW
So 110db would require the speaker to be 93db/1 watt - Plus a bit to allow for thermal compression, maybe 2 or 3 db.
So you would need the speaker to be 95-96 db/ 1 watt efficiency.
That is the sort of efficiency a 120 litre 15 reflex cab can achieve.....
OMG my Daughter has gone prog rock!
http://www.strangeredearth.com/videos/
Back to Top
MarjanM View Drop Down
Old Croc
Old Croc
Avatar

Joined: 10 February 2005
Location: Macedonia
Status: Offline
Points: 7404
Post Options Post Options   Thanks (0) Thanks(0)   Quote MarjanM Quote  Post ReplyReply Direct Link To This Post Posted: 29 January 2020 at 1:40pm
Originally posted by Xoc1 Xoc1 wrote:

50 watts is 17 dbW
So 110db would require the speaker to be 93db/1 watt - Plus a bit to allow for thermal compression, maybe 2 or 3 db.
So you would need the speaker to be 95-96 db/ 1 watt efficiency.
That is the sort of efficiency a 120 litre 15 reflex cab can achieve.....

BMS12S330 90lit box tuned at about 45-47hz would do that too. Wont go super low but it will be punchy just enough.
Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713
Back to Top
APW View Drop Down
Young Croc
Young Croc
Avatar

Joined: 13 November 2012
Location: New Romney Kent
Status: Offline
Points: 739
Post Options Post Options   Thanks (0) Thanks(0)   Quote APW Quote  Post ReplyReply Direct Link To This Post Posted: 29 January 2020 at 3:49pm
A Beyma SM212 in a 85Ltr box tuned to about 47Hz would also do that at a about half the cost of the BMS...

It should be able to reproduce just over 114dB @ 50watts with a -3dB point of 47Hz and a -10 dB of about 37Hz




Back to Top
Xoc1 View Drop Down
Registered User
Registered User


Joined: 15 October 2012
Location: Devon UK
Status: Offline
Points: 230
Post Options Post Options   Thanks (0) Thanks(0)   Quote Xoc1 Quote  Post ReplyReply Direct Link To This Post Posted: 29 January 2020 at 8:43pm


The BMS 12S330 is a very capable driver It looks capable of soaking up a lot of power and providing a good low frequency response in a small box, Not so efficient though.
Could not get a decent response in Hornresp with the size and tuning suggested by Marjan
The Beyma SM212 seems just about on the money as APW suggested.
Sim shows BMS in grey and Beyma in black, in boxes with size and tuning suggested, both at 20Volts (50w @ 8 R)
OMG my Daughter has gone prog rock!
http://www.strangeredearth.com/videos/
Back to Top
Monkeys View Drop Down
Registered User
Registered User


Joined: 30 August 2012
Location: Melbourne - Aus
Status: Offline
Points: 429
Post Options Post Options   Thanks (0) Thanks(0)   Quote Monkeys Quote  Post ReplyReply Direct Link To This Post Posted: 29 January 2020 at 9:25pm
Thanks again for the replies everyone.

So what if I were to sacrifice some loudness and some low end response to keep the box size down, somewhere within 30l max wouod be ideal. Id rather sacrifice loudness and efficiency than low end range. 

Let's call -3db at 60hz the minimum cutoff for bass response, and 30l the cab size? Is that doable? What sort of efficiency is possible?
Back to Top
Xoc1 View Drop Down
Registered User
Registered User


Joined: 15 October 2012
Location: Devon UK
Status: Offline
Points: 230
Post Options Post Options   Thanks (0) Thanks(0)   Quote Xoc1 Quote  Post ReplyReply Direct Link To This Post Posted: 29 January 2020 at 9:37pm
The Beyma would reach x max at about 150w (34.6v)and 120db so a bigger amplifier would be possible. As long as the amp is efficient the increase in headroom would be useful. Peak efficiency is about 98db@ at 66hz
 Could do with a high pass filter to be safe at higher power levels - Hornresp is suggesting about
38hz with a 4th order Butterworth - Probably good for its 350W rating in real world (adding 3db for losses). Grey is 1 watt black is 150w without losses Filter shows displacement
Edit I see that even this is not good enough for you - what you want is what we all could do with a small miracle - If such a thing existed we would all be using it!


Edited by Xoc1 - 29 January 2020 at 9:40pm
OMG my Daughter has gone prog rock!
http://www.strangeredearth.com/videos/
Back to Top
 Post Reply Post Reply Page  123 4>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.148 seconds.