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Offline Simon Briggs  
#1 Posted : 29 June 2013 16:33:15(UTC)
Simon Briggs


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Looking about for suitable drivers, any ideas?

This is a possibility

15" Bass Unit

Edited by user 29 June 2013 16:34:02(UTC)  | Reason: Not specified

Offline ashleym  
#2 Posted : 29 June 2013 21:09:43(UTC)
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Form the same site you have the other subs woofer from

Dayton

OK Qts but not very efficient.

another sub

Or you could take the TRK route and use a sub. THis has better Qts but doesnt cover much up the frequency range. OK its only a 12", so use 2!!

Why dont you just go for something like this, plenty of grunt and its brother is appearing in a DBL near you tonight

PD

What is the rest of the speaker? I am negotiating an OB speaker domestically at the moment

Visaton no box

another OB

yet another OB
Offline ashleym  
#3 Posted : 30 June 2013 17:13:48(UTC)
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Another name popped into my head. Apparently one of the largest driver manufacturers around

fostex
Offline Pete_w  
#4 Posted : 30 June 2013 18:29:28(UTC)
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Originally Posted by: ashleym Go to Quoted Post
I am negotiating an OB speaker domestically at the moment


A genuine question, Ashley. Please educate me. Why? Why do an OB? Seems to me that you're creating what I'd call, in laymans terms, a more-or-less spherical dipole. I had enough trouble positioning my Logans (see posts passim) which are dipoles but are at least a line source, so I have to worry (just!) about rear radiation, and not so much about floors, ceilings and sidewalls as well. A moving coil OB must be about the worst thing in the world to position, and (at least in many houses I could think of) is more or less bound to cause a, erm, interesting domestic debate about the continuation of any form of relationship, with "choices" being involved [ :-) ]. So what is it that they do so well that makes people persevere with 'em? I speak as one who's only ever heard one or two at shows, so I don't really know what they can do...

Thanks
Pete
Offline ashleym  
#5 Posted : 30 June 2013 21:45:47(UTC)
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Pete,
Please do ask, this is what these forums are for. I am happy to be wrong or right!! I welcome any other thoughts.

With an OB its not what you're getting so much as what you are not. No box. No reflected sound within the box, no sound reflected through cone, no getting the right fill in a box, no fine tuning of box size, no real worries about box colouration, simple construction (but still paying attention to detail), no worries about sealing a box.

I understand you get sound all over the place with an open speaker. With the Visaton I linked to it uses a full range unit for everything above the bass so you will get beaming up through the frequency range. But I think you get a bit of uneveness in the FR out back as a midrange in a 3-way also beams. If I go for a 3-way I might have a rear facing tweeter padded down to add some air as some posh speakers do.

Back to the dipole bit. You get a figure of 8 dipole rather than full spherical down to the frequencies bass rolls around an open baffle, 100hz ish. This will be familiar to you with your MLs. Hassle to get working in a room, yes.....I have some room in the living room, it is a 30' foot long, 16' wide sixties living room (full of floor standing ceramic pots at the moment but that changes, I pretend they are helmholtz resonators).

You do need some efficiency with the drivers but people report success with Eminence etc instrument speakers/PA- Precision Devices for another example. But you can get this efficiency quite cheaply if you are prepared for a speaker with one or two 15" drivers a side. This is where it gets tricky domestically, at least you can see through your MLsThumpUp

But why OB? When I were a lad and taking things apart a bit more I heard a great improvement in sound when I took some drivers out of boxes. I was also taken aback the first time I heard some Wilsons with their lack of cabinet sound. One of the advantages of ESL is their lack of a closed cabinet (taken hybrids). And the idea appeals. I have heard the big Jamos and liked them. I still havent heard the Gradients but look at the review in the Critic and they are distributed by DNM over here- now that is a man/company who know a good speaker when they hear one. I mean you Rehdeko.

This is the main source for the whys and wherefores.

linkwitzlab

Offline Pete_w  
#6 Posted : 04 July 2013 16:00:38(UTC)
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Thanks, Ashley, very interesting. So you're basically looking for the same things that I get out of my panels, aren't you? But with a DIY element (thus, possibly, leading to higher performance, uncompromised by cost/manufacturability constraints). Makes sense.

In terms of domestic acceptability, do you have to go "open" all the way down, or could you put a bass driver in a sealed box? Still quite "fast", but significantly smaller...?
Offline mat  
#7 Posted : 05 July 2013 13:12:23(UTC)
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The italian firm B&C make some excellent large units, short throw high spl, excllent cooling, linearity and durability. No uk distributor but you could try and buy from the continent?
Offline Simon Briggs  
#8 Posted : 06 July 2013 08:09:46(UTC)
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Really after something around 90 db/w optimised for a big sealed box the SB acoustics is the closest I have found thus far
Offline ashleym  
#9 Posted : 06 July 2013 17:08:33(UTC)
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If money is no object then get some custom units from Audiotechnology

audiotech

You can order up the exact spec you want but you end up paying about £600 each for a 15"
Offline Simon Briggs  
#10 Posted : 06 July 2013 19:29:09(UTC)
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Not unreasonable as I paid nearly that for 15" Focal units some years ago!!

I have looked at the AudioTech units and they are a real possibility
Offline al2002  
#11 Posted : 14 September 2013 17:32:00(UTC)
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Originally Posted by: darkmatter Go to Quoted Post
Looking about for suitable drivers, any ideas?

This is a possibility

15" Bass Unit


As a newcomer to this forum I am a bit late on this thread. Have you already got the bass drivers?

I expect you know already that there are many ways to move forward from conventional subs to dipole subs to servo subs to subs firing into a corner using DSP.

Can you tell us what the intended application is and the budget?





Offline al2002  
#12 Posted : 14 September 2013 17:47:07(UTC)
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Originally Posted by: darkmatter Go to Quoted Post
Looking about for suitable drivers, any ideas?

This is a possibility

15" Bass Unit



P.S:- The bass unit you linked to looks like it might be happier in a vented enclosure.
Look at the Vas, it is very large, this will need a huge sealed enclosure. Also, you can now find many other drivers with greater Xmax.

Offline Simon Briggs  
#13 Posted : 14 September 2013 17:53:50(UTC)
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Originally Posted by: al2002 Go to Quoted Post
Originally Posted by: darkmatter Go to Quoted Post
Looking about for suitable drivers, any ideas?

This is a possibility

15" Bass Unit



P.S:- The bass unit you linked to looks like it might be happier in a vented enclosure.
Look at the Vas, it is very large, this will need a huge sealed enclosure. Also, you can now find many other drivers with greater Xmax.



I have checked that out in many different enclosure options. This is one of the most suitable drivers I have seen with suitable characteristics. A large sealed enclosure works out absolutely fine for me
Offline al2002  
#14 Posted : 14 September 2013 20:42:10(UTC)
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Good to know you find this drive unit meets your needs.

I am curious to know what you found to be the optimum enclosure volume. I modeled this drive unit in sealed enclosures ranging from very small to very large and could not find a really satisfactory alignment without using a Linkwitz Transform.

Edited by user 14 September 2013 20:42:45(UTC)  | Reason: Not specified

Offline Martin Colloms  
#15 Posted : 16 September 2013 11:37:02(UTC)
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for speedy bass , not necessarily the most bass, I favour Qtc at 0.5 to 0.6 for a sealed box.

Thus I would trade , for a given allowable box volume a 12inch for a 15 inch to achieve it.

I am wary of too much equalisation and electronics ahead of it as with more supplies, power noise, extra ground routes

immediacy and fidelity may be impaired in favour of a notional text book frequency response.

The box size implies lots of panel area, so massive bracing and damping is a prerequisite if the journey is to be worth the effort and expense.

Martin Colloms
Offline Simon Briggs  
#16 Posted : 16 September 2013 19:15:50(UTC)
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Yes my preferred alignment has always been around Q=0.6 or a bit below for a sealed system. As a teen I built one of the bigger 12" based systems to the disdain of my parents BigGrin

With suitable volume fill and experimentation the likely box vol for this driver will be around 230 litres for a single 15"

As my proposal calls for a dual 15" system that is a sizable enclosure but not out of kilter for the type of thing that I go for!!

A solid 20Hz or slightly below perhaps to the magic 32' register or 16hz is the likely performance with this driver and given volume will yield

the kind of free and expressional (sic) performance that I cannot find in most commercial systems excepting those around 100K and above!!

Timing and dynamics, will I feel, stand a good chance of expressing themselves with this vehicle.

I have tried equalised systems in my own designs and have always been more aware of the compromises above the gains with them and even with

some expensive commercial product too.

Simon Smile

Edited by user 16 September 2013 19:17:48(UTC)  | Reason: Not specified

Offline Martin Colloms  
#17 Posted : 18 September 2013 18:11:38(UTC)
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prefer slightly limited low bass but clean and quick, to equalized and overcooked bass extension

Very big speaker bass can be addictive but they are hard to set up for an even overall balance and fast timing

Martin Colloms
Offline Simon Briggs  
#18 Posted : 18 September 2013 18:19:56(UTC)
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Yes timing is top of my priorities, it took me months to fine tune my big speaker to achieve good bass extension together with a fine sense of involvement; its possible replacement will be more of a challenge given my goal of true high level 32' bass.

Edited by user 18 September 2013 18:24:23(UTC)  | Reason: Not specified

Offline Simon Briggs  
#19 Posted : 02 November 2013 21:09:32(UTC)
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Originally Posted by: al2002 Go to Quoted Post
Originally Posted by: darkmatter Go to Quoted Post
Looking about for suitable drivers, any ideas?

This is a possibility

15" Bass Unit


As a newcomer to this forum I am a bit late on this thread. Have you already got the bass drivers?

I expect you know already that there are many ways to move forward from conventional subs to dipole subs to servo subs to subs firing into a corner using DSP.

Can you tell us what the intended application is and the budget?







Resurrecting this thread

Budget and use. The intended use is for a full range 3 way design I have plenty of mids and tweeters lying around the place so selecting these will be easy!!

It is fixed that the project will be a sealed box that's it!

Budget around £300 per bass driver I will be selecting a low Q design so they will end up working in a large box around ~ 200L +

System Q = 0.6 ish

Offline ashleym  
#20 Posted : 03 November 2013 13:35:21(UTC)
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Without wanting to sound like I am telling you off......

What are you doing here this is going to be news or different to what you have built before or already own? Is it the bass level and extension? Just asking to see what direction you are taking
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