Hi!
A while ago someone gave me a pair of EV SP12B full/widerange drivers.
I kept them in storage for almost a year before I dug them up and put them in a pair of (small) open baffles a few weeks ago. I cross over to a pair of DIY multicell horns at ~900Hz.
OB works fairly well in my assymmetric livingroom but even with a passive EQ network and a low DF amp the bass is a bit light.
Larger baffles is not really an option and there´s no room for properly placed dipole subs so I´m looking for some kind of folded baffle solution.
I believe adding wings at 90 degrees back from the baffles might cause resonance problems, but what if I fill the cavity with some damping material?
Might even add perforated backpieces to keep the stuffing in place (four cats in the house...).
I understand that the dipole pattern would be compromised, though I´m not sure that would be a bad thing. Depending on the hole pattern of the backpieces this may approach aperiodic tuning rather than OB.
I guess the only way to find out if this works for me, in my room, is to try it but I´m curious to hear what other people might have to say about the concept.
I´m a sworn enemy to boomy bass
A while ago someone gave me a pair of EV SP12B full/widerange drivers.
I kept them in storage for almost a year before I dug them up and put them in a pair of (small) open baffles a few weeks ago. I cross over to a pair of DIY multicell horns at ~900Hz.
OB works fairly well in my assymmetric livingroom but even with a passive EQ network and a low DF amp the bass is a bit light.
Larger baffles is not really an option and there´s no room for properly placed dipole subs so I´m looking for some kind of folded baffle solution.
I believe adding wings at 90 degrees back from the baffles might cause resonance problems, but what if I fill the cavity with some damping material?
Might even add perforated backpieces to keep the stuffing in place (four cats in the house...).
I understand that the dipole pattern would be compromised, though I´m not sure that would be a bad thing. Depending on the hole pattern of the backpieces this may approach aperiodic tuning rather than OB.
I guess the only way to find out if this works for me, in my room, is to try it but I´m curious to hear what other people might have to say about the concept.
I´m a sworn enemy to boomy bass
I've experimented with covering the back of an open baffle with blankets, carpet or other acoustic dampening materials. The results I found were the radiation pattern changes more into a hypercardiod response. The rear wave will be attenuated, but, the pattern will become closer to the original figure 8 the farther the frequency goes down. Also, baffle wings are a good idea especially for smaller spaces, but it is best to have them spread out some to minimize cavity resonance.
hope this helps
hope this helps
I have a pair of the EV SP-12's. They are similar but have a much larger alnico magnet structure that the SP-12B, a whizzer cone and very high sensitivity. I tried them in a number of different cabinets and was not happy with either the weak bass or the cabinet coloration. I then tried them in a pair of Altec 816A front horn loaded reflex cabinets designed for 15" drivers. I used the aluminum adapter ring that holds a 12" Bozak B-199 woofer in a 15" driver cutout with the two tweeters hung out front to mount the 12" EV's in the Altec cabinet. The SP-12's are run full range and the top end is helped with a small 3x9" HF horn and compression driver with 1st order cap filter and series resistor. My tweeter horns come in around 7+ KHz. How do these peform? In a word WOW! These are the most SET friendly speakers I own. They can fill a large room with a couple of watts. The bass is not deep but it is accurate and adequate given the sensitivity achieved. I am not bothered by any cabinet sound. This combo gets my Two Thumbs Up! BTW, if you want deep powerful bass these drivers are the wrong choice.
I recommend that you try these cabinets for your SP12B's.
http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/cabinets/816A LF Speaker Cabinet.pdf
I recommend that you try these cabinets for your SP12B's.
http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/cabinets/816A LF Speaker Cabinet.pdf
I use the SP12b on a shallow U frame crossed over to Alpha 15A in a H frame. The EV is rolled off around 200 hz. The Alpha is powered using a small plate amp. I used a Fostex T90A supertweeter on top to supplement the high end. I used Martin King's worksheets to develop the design. Very satisfied with the results.
Bill
MobileMe Gallery
Bill
MobileMe Gallery
Dave,
I just discovered that link to Altecpro was dead and deleted the link in a refreshed version of my old post. The 816A is the bass horn and a reflex port just below that looks exactly like the bottom 15" woofer horn on the famous Altec A-7 cabinet. It has no room to install a 511B or 811B sectoral horn within the port as does the A7, so it is a much shorter cabinet. I use my 816A's with the EV SP-12's turned on their sides which makes them narrower and saves floor space.
I don't remember if I mistakenly referred the cabinet as a 416A. That is a driver. I get those numbers confuz-ed. Rob
https://www.google.ca/search?q=alte...m%2Fforum%2Fshowthread.php%3Ft%3D264;900;1171
It might be best to just shelve all those late 50's and 60' drivers. They make nice museum pieces but compared to today's technology they just can't perform. Most had an Fs of 50 to 70Hz and required a large reflex cabinet. They are also very fragile when used with modern amps and wide dynamic range material. You can blow one even at moderate levels. It was the best we had in those days but even the lowest priced Goldwood models are better today.
There may be some truth to what you are saying, but I am not concerned about deep bass. I have 4 - 15" Emminence drivers on open baffles that cover the bottom end handily. On the top I have a pair of Raven 1 ribbon tweeters sitting around that can be pressed into service to cover the top end. Keep in mind this is about the process as much as it is the result. There must be something to them as the owner built them himself and held on to them for over 50 years. The only reason he is letting them go as he is moving to a condo and the wife won't let them in. The pair I was given were in use in a wood shop in the original enclosures behind the original EV grill material up until last week. So, I already have a large-ish rear horn enclosure to play with, but I was just wondering if there was a way to really make these shine. I guess I will find out.
And about them being delicate. I will take that as a word of caution. These are not to be used for Black Sabath or AC/DC at level. Save them for jazz vocals and places where they can shine.
And about them being delicate. I will take that as a word of caution. These are not to be used for Black Sabath or AC/DC at level. Save them for jazz vocals and places where they can shine.
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I hate to bump an old thread, but i'm looking for any additional insights or comments people may have on this topic.
I picked up a set of the ElectroVoice SP12 drivers with the big white coffee can sized alnico on the back.
I already own Klipsch Heresy's and Cornwalls, so i don't want any more big wooden boxes. I had aristocrat cabs, but got rid of them years ago. I was thinking about building these into an open baffle design.
Could i full-range it, or should i add tweeter? Trying to keep this simple.
Does anyone have suggestions as to baffle dimensions or similar projects i could use for help?
thanks in advance
I picked up a set of the ElectroVoice SP12 drivers with the big white coffee can sized alnico on the back.
I already own Klipsch Heresy's and Cornwalls, so i don't want any more big wooden boxes. I had aristocrat cabs, but got rid of them years ago. I was thinking about building these into an open baffle design.
Could i full-range it, or should i add tweeter? Trying to keep this simple.
Does anyone have suggestions as to baffle dimensions or similar projects i could use for help?
thanks in advance
couldn't tell you about tweet, but using an "phy style" (5' tall, 16" wide front panel and 24" deep hinged wings using 12" full range driver), I still needed bass reinforcement, not subwoofer, bass reinforcement. Especially for rock music. But it had a midrange purity that was nice. Hump of midbass bass at 140hz then dropped like a rock.