Well..... I just dont' know!
If your 7" woofers are doing well now, then the LTA should be better. What's the Fs on the 7s?
I'm very happy with the bass coming out of the Peerless SLS 12" on my new OB rig, (Fs 28Hz) but it may not match well with the Beta 8A. The 12LTA should mate very well, sonically.
How wide and tall a baffle do you plan?
If your 7" woofers are doing well now, then the LTA should be better. What's the Fs on the 7s?
I'm very happy with the bass coming out of the Peerless SLS 12" on my new OB rig, (Fs 28Hz) but it may not match well with the Beta 8A. The 12LTA should mate very well, sonically.
How wide and tall a baffle do you plan?
Hello SimonTY,
I have been in the same boat as you before, searching for drivers for a nice OB system with easy to source components in the UK.
I plan to use Alpha-15s for my system, but as you want to go with 12" woofers, I will recommend the Skytronic range of woofers. I havn't tried them myself but the specifications on a lot of their woofers look ideal for OB systems.
Here are some useful links
Example of 12" skytronic woofer
http://cgi.ebay.co.uk/Skytronic-902...4&_trkparms=72:1301|66:2|65:12|39:1|240:1318
Link to product range
http://www.skytronic.co.uk/product/index.php?s=902.195
TS parameters for Skytronic woofers (worth reading through)
http://www.skytronic.com/rsc/doc/thielesmall_902127.pdf
The Skytronic range can be found in lots of UK online electronics stores, just use google or ebay to find them.
Also, an excellent site with a wide range of PA drivers is http://www.bluearan.co.uk/
They stock Eminence, Beyma, and a whole host of other brands. I have used them before and they seem to be very good.
I have been in the same boat as you before, searching for drivers for a nice OB system with easy to source components in the UK.
I plan to use Alpha-15s for my system, but as you want to go with 12" woofers, I will recommend the Skytronic range of woofers. I havn't tried them myself but the specifications on a lot of their woofers look ideal for OB systems.
Here are some useful links
Example of 12" skytronic woofer
http://cgi.ebay.co.uk/Skytronic-902...4&_trkparms=72:1301|66:2|65:12|39:1|240:1318
Link to product range
http://www.skytronic.co.uk/product/index.php?s=902.195
TS parameters for Skytronic woofers (worth reading through)
http://www.skytronic.com/rsc/doc/thielesmall_902127.pdf
The Skytronic range can be found in lots of UK online electronics stores, just use google or ebay to find them.
Also, an excellent site with a wide range of PA drivers is http://www.bluearan.co.uk/
They stock Eminence, Beyma, and a whole host of other brands. I have used them before and they seem to be very good.
That skytronic 12 looks interesting.
OK, it's just a plastic cone woofer, but at 30 quid, not a bad deal.
The low Fs and Q of .49 should work well in OB.
Going to be a lot like my Peerless SLS, but less refined. May not matter if you use it down low.
Simon, give us an idea of baffle size and I'll run some sims for you.
OK, it's just a plastic cone woofer, but at 30 quid, not a bad deal.
The low Fs and Q of .49 should work well in OB. Going to be a lot like my Peerless SLS, but less refined. May not matter if you use it down low.
Simon, give us an idea of baffle size and I'll run some sims for you.
Bl0*dy h€ll Will! £30 for TWO 12" woofers, that is super-cheap...
And with those specs, I think you have saved me from a potentially inferior and more expensive choice there! Thank you sir.
Pertinent specs of the cheapo Ebay woofer:
* Fs: 29hz
* Re: 7.1
* Qts: 0.49
* SPL: 88.5
* Xmax: 6mm (not specifically stated as one way...)
The sensitivity is the only real weak point I can see, but with two in parallel we're back up to 94.5dB, which is a fine starting point IMHO.
Simon
And with those specs, I think you have saved me from a potentially inferior and more expensive choice there! Thank you sir.
Pertinent specs of the cheapo Ebay woofer:
* Fs: 29hz
* Re: 7.1
* Qts: 0.49
* SPL: 88.5
* Xmax: 6mm (not specifically stated as one way...)
The sensitivity is the only real weak point I can see, but with two in parallel we're back up to 94.5dB, which is a fine starting point IMHO.
Simon
panomaniac said:That skytronic 12 looks interesting.
OK, it's just a plastic cone woofer, but at 30 quid, not a bad deal.
Going to be a lot like my Peerless SLS, but less refined. May not matter if you use it down low.
Simon, give us an idea of baffle size and I'll run some sims for you.
It's a great deal isn't it?! Well worth trying... I'm very glad I didn't order any Eminence woofers yet.
My current baffles are 30cm (12") wide. They could be 35cm wide tops. The side wings could be at least 20cm I'd say.
Thanks a lot for the help guys.
Simon
Good find on those 12s. I like the name, too. =)
You should use 2 per side, not only does it give you twice the surface area, you get 6dB more at the same input voltage (you'll need it) as well as a 4 Ohm load for the crossover. It's win/win.
Have a look at x-baffle spreadsheet. It gives a good idea of what a driver will do on baffle. You can add wings by adding width. Have fun!
Oh, BTW, you can't do 2 drivers on a board with x-baffle, but just add 6 dB.
Also good to note is that if you simulate a closed box with a Q of about .46, you will see the low end roll-off of the driver on a reasonably sized baffle. FWIW.
You should use 2 per side, not only does it give you twice the surface area, you get 6dB more at the same input voltage (you'll need it) as well as a 4 Ohm load for the crossover. It's win/win.
Have a look at x-baffle spreadsheet. It gives a good idea of what a driver will do on baffle. You can add wings by adding width. Have fun!
Oh, BTW, you can't do 2 drivers on a board with x-baffle, but just add 6 dB.
Also good to note is that if you simulate a closed box with a Q of about .46, you will see the low end roll-off of the driver on a reasonably sized baffle. FWIW.
Thanks Pan,
I'm just playing about in Edge.
I think on a 70-80cm wide U-baffle, I'll need to crossover at about 50-90hz 1st or even second order for good results - that should roughly cancel the rise into the dipole peak and make things vaguely flat. Then the bottom can be brought up a further 6dB with Graham's excellent T-bass cct.
Need to get to bed now, I'll investigate further tomorrow.
Simon
I'm just playing about in Edge.
I think on a 70-80cm wide U-baffle, I'll need to crossover at about 50-90hz 1st or even second order for good results - that should roughly cancel the rise into the dipole peak and make things vaguely flat. Then the bottom can be brought up a further 6dB with Graham's excellent T-bass cct.
Need to get to bed now, I'll investigate further tomorrow.
Simon
Attachments
just 4 fun I ran sims on 4 drivers on your baffle.
The Skytronic (x2)
The Beta 12LTA
Peerless SLS 12
Alpha 15A
This should give you some idea of how they work out.
You can see that the Apha 15A is the flattest, but also the lowest level. You won't have to fight the rise as much on the Alpha.
The 2 Skytronics in parallel track the Beta LTA 12 pretty well, but will play lower. Being a 4 ohm load, you won't need as large an inductor. You may get more bass out of the 2 Skytonics, as the sim does not really show 2 drivers, I just boosted the level 6dB
The Skytronic (x2)
The Beta 12LTA
Peerless SLS 12
Alpha 15A
This should give you some idea of how they work out.
You can see that the Apha 15A is the flattest, but also the lowest level. You won't have to fight the rise as much on the Alpha.
The 2 Skytronics in parallel track the Beta LTA 12 pretty well, but will play lower. Being a 4 ohm load, you won't need as large an inductor. You may get more bass out of the 2 Skytonics, as the sim does not really show 2 drivers, I just boosted the level 6dB
Attachments
Hi Michael,
Whenever I ran XLBaffle for a single Alpha-15A it came out much higher than your simulation shows.
Hi Simon,
As you note - that Skytronics is not efficient, esp for OB.
Two in parallel still don't equal one Beta-15A, even when consuming twice the power.
The most important aspects for LF are displacement/cone area and high VAS.
You are 'Edge'ing a baffle capable of mounting more than 12s, and I am not aware of any 12s which can compete with the Beta-15A for value. I have an 18" driver on an 18" wide baffle - just requires a little care when cutting and bolting.
There are a couple of Skytronic 15s too, though again these are not especially efficient for OB.
Wonder if you have any hair left......... Graham.
PS Also of interest for an easy flat OB response would be 4x Visaton WS25E, but then you'd be over £100 per channel.
Whenever I ran XLBaffle for a single Alpha-15A it came out much higher than your simulation shows.
Hi Simon,
As you note - that Skytronics is not efficient, esp for OB.
Two in parallel still don't equal one Beta-15A, even when consuming twice the power.
The most important aspects for LF are displacement/cone area and high VAS.
You are 'Edge'ing a baffle capable of mounting more than 12s, and I am not aware of any 12s which can compete with the Beta-15A for value. I have an 18" driver on an 18" wide baffle - just requires a little care when cutting and bolting.
There are a couple of Skytronic 15s too, though again these are not especially efficient for OB.
Wonder if you have any hair left......... Graham.
PS Also of interest for an easy flat OB response would be 4x Visaton WS25E, but then you'd be over £100 per channel.
Cheers for that Pan.
It looks like I'll get a useful bit of extra extension from the cheapo plastic woofers. Is that due to the lower Fs?
I think I'll order some as they're so cheap it doesn't matter if they're nothing special and that simulation looks pretty good to me.
Oh btw, my 7" woofers have an Fs of 43hz.... which is also about as low as they play - subjectively. The bass isn't well balanced though, I still have more upper bass than midbass so I ought to try and finish that design and use what I learn in the next one.
Simon
It looks like I'll get a useful bit of extra extension from the cheapo plastic woofers. Is that due to the lower Fs?
I think I'll order some as they're so cheap it doesn't matter if they're nothing special and that simulation looks pretty good to me.
Oh btw, my 7" woofers have an Fs of 43hz.... which is also about as low as they play - subjectively. The bass isn't well balanced though, I still have more upper bass than midbass so I ought to try and finish that design and use what I learn in the next one.
Simon
Graham Maynard said:
lol, not much now Graham!
Bear in mind my Edge sim included side wings. I can't really have anything wider than about 35cm tops! It's frustratingly close to 15" and that is why I toyed with the idea of a 15+12 combo as that might just fit in the space..
Then these Skytronic babies came along, and with ~1400cm^2 of area for 2 x 12" that's almost 400cm^2 more surface area than my already reasonable 4 x 7" combo.... now factoring in the higher Qts and much lower Fs I should see significantly better bass, for very little dollar.
I have also considered that 2 x 12LTA will have more output (but needs just slightly more EQ for a flat response), and a 12+15" even more - but do I need it?
Simon
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