Hello Friends,
Couple of months ago i ended up in building a pair of open baffle speakers based on lampizator p17 project. This is my very first speaker project. I used the recommended saba greencones for tweeters and mid but choose eminence Deltalite neo speakers for the woofers. The bass was not low enough since the
Resonant Frequency (Fs) is 42 Hz and frequency Response is 54 to 3,700 Hz
The end result was a top heavy and low bass output which was not satisfying to me. Later on i did biamping using minidsp but that didn't help much and when i tried to increase the low end thru mini dsp parametric equalizers the end result was not smooth. I am getting listening fatigue very soon.
The only other option at this time seems to replace the woofer drivers with different ones and instead of a u frame design.. i would prefer for a closed bass box. This in turn would be a hybrid open baffle design.
I would like you guys to suggest some good 15" drivers that can go low and can be be a perfect match with the rest of my design.
Any other suggestions regarding this hybrid approach is also welcomed.
Thanks in advance
Couple of months ago i ended up in building a pair of open baffle speakers based on lampizator p17 project. This is my very first speaker project. I used the recommended saba greencones for tweeters and mid but choose eminence Deltalite neo speakers for the woofers. The bass was not low enough since the
Resonant Frequency (Fs) is 42 Hz and frequency Response is 54 to 3,700 Hz
The end result was a top heavy and low bass output which was not satisfying to me. Later on i did biamping using minidsp but that didn't help much and when i tried to increase the low end thru mini dsp parametric equalizers the end result was not smooth. I am getting listening fatigue very soon.
The only other option at this time seems to replace the woofer drivers with different ones and instead of a u frame design.. i would prefer for a closed bass box. This in turn would be a hybrid open baffle design.
I would like you guys to suggest some good 15" drivers that can go low and can be be a perfect match with the rest of my design.
Any other suggestions regarding this hybrid approach is also welcomed.
Thanks in advance
Reading your previous threads on the speaker project you mention makes me think that the problem is your lack of knowledge about speaker building, especially an open baffle type speaker, that was your downfall. I think that your idea to convert the woofer to a closed box type is a good one. If you don't have a separate amplifier for the woofer, you will need to carefully match the driver SPL to the midrange/tweeter - I am not sure you know how to plan for this (again, a speaker design problem). If you use a separate amplifier for the woofer and use the miniDSP you mentioned to implement the crossover and level adjustment you will have the highest chance of success. You might also conceive of a solution comprised of your mid/tweeter combo with the lampizator as one speaker, plus one or two subwoofers to fill in the bass.
How high in frequency will the new woofer go? Or, similarly, how low in frequency can your midrange play cleanly or where do you want to cross over between these two drivers?
How large is your listening space and how loudly do you want to reproduce the bass in it?
What kind of bass sounds are you trying to reproduce? Guitar? Sax? Electric Bass? Drums? Orchestral sounds or rock/modern music? Etc.
How far from the speakers is your listening position?
How low in frequency do you want to go? 50Hz? 40Hz? 30Hz? 20Hz?
There is absolutely no reason to use a 15" driver, and a different sized woofer might be just as good or even better depending on what your answers are to the questions above!
How high in frequency will the new woofer go? Or, similarly, how low in frequency can your midrange play cleanly or where do you want to cross over between these two drivers?
How large is your listening space and how loudly do you want to reproduce the bass in it?
What kind of bass sounds are you trying to reproduce? Guitar? Sax? Electric Bass? Drums? Orchestral sounds or rock/modern music? Etc.
How far from the speakers is your listening position?
How low in frequency do you want to go? 50Hz? 40Hz? 30Hz? 20Hz?
There is absolutely no reason to use a 15" driver, and a different sized woofer might be just as good or even better depending on what your answers are to the questions above!
Thank you very much for your reply.. you have guessed it correctly i have no prior experience in speaker building... the open baffle speaker is my very first attempt and the reason to choose this particular design is due to the reviews read and the simplicity of the design.
now regarding the questions
I have a tube amp for my high and mids + a tripath amp for my woofers.
The saba greencone midrange can go as low as 70hz but i plan to crossover around 500hz.
The lowest frequency i would prefer around 20-30hz.
i mostly listen to pop music so it would be mostly drums and guitars
The current listening space is medium sized room. I am typically 13 feet away from my speakers. I am really not into loud bass.. but interested in making the sound fuller with just enough boom and punch
I was debating whether to replace my existing 15 woofers or just build/add a subwoofer or redesign the entire system. But since i have the cabinet built already which can accommodate 15 woofer so i thought of replacing the woofers and close the back u-frame. and save some bucks on wood work.
rocky,
since you now have the DSP, i would keep the current 3 way set up and add subwoofer(s)
the problem with your current system could be the u frame resonances.
get rid of the u frame and have your greencones and 15" woofer on flat baffles.
you can EQ the 8" greencone and 15" woofer flat.
the 8"-15" croosover point should be around 250Hz.
and then you can dial in your subs around 80Hz.
subs could be monopole or ripole.
since you now have the DSP, i would keep the current 3 way set up and add subwoofer(s)
the problem with your current system could be the u frame resonances.
get rid of the u frame and have your greencones and 15" woofer on flat baffles.
you can EQ the 8" greencone and 15" woofer flat.
the 8"-15" croosover point should be around 250Hz.
and then you can dial in your subs around 80Hz.
subs could be monopole or ripole.
If you enclose the U-frame to make a closed box for the 15-inch driver what will the internal volume be of the box? This will be Vb. Post that volume (in liters) here.
Knowing Vb will help you choose the driver for your closed box. You can not just say "what is a good driver" and think that if you put it in some random enclosure things will turn out "good". You might consider reading up on the basics of enclosure design and why the enclosure and the driver need to be matched. If you knew that you would be able to choose a driver yourself, or at least promulgate a couple of options that you are considering.
If you want some links to online reading, ask and people will chime in with some info.
Knowing Vb will help you choose the driver for your closed box. You can not just say "what is a good driver" and think that if you put it in some random enclosure things will turn out "good". You might consider reading up on the basics of enclosure design and why the enclosure and the driver need to be matched. If you knew that you would be able to choose a driver yourself, or at least promulgate a couple of options that you are considering.
If you want some links to online reading, ask and people will chime in with some info.
You should be able to run a sealed box 15" between 30-250hz, but that would require a driver with low Fs, high xmax and a lot of EQ and amp power.
However with such a set up you won't be able to match the dynamics of your greencones.
Go ahead and build your sealed boxes. If you don't like the result, you can always use them as true subs (30-80Hz).
Oh, and you will probably need a driver like this:
Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm
However with such a set up you won't be able to match the dynamics of your greencones.
Go ahead and build your sealed boxes. If you don't like the result, you can always use them as true subs (30-80Hz).
Oh, and you will probably need a driver like this:
Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm
Here are two alternatives you might try before spending more $$$ on new drivers:
1. Stuff the U frame cavity with insulation material such as Bonded Logic NaO U-frame
2. Use your 15" Deltalite in a lampizator p13 type vented cabinet
Project13 speakers
1. Stuff the U frame cavity with insulation material such as Bonded Logic NaO U-frame
2. Use your 15" Deltalite in a lampizator p13 type vented cabinet
Project13 speakers
When I tried using the MiniDSPs to flatten open baffle bass, I quickly ran into the 0.9v output limit, and got serious clipping. I had to add gain stages to get good results.
I wonder if a Linkwitz transform would get that driver down to a satisfying frequency?
Done well in the required sealed enclosure, it would have the speed to match up nicely with OB.
Read up on the LT over on Rod Elliott's site. And I wonder if the Mini-DSP could do the LT?
EV3
Done well in the required sealed enclosure, it would have the speed to match up nicely with OB.
Read up on the LT over on Rod Elliott's site. And I wonder if the Mini-DSP could do the LT?
EV3
The volume would be around 98 litres. The box is 70cm high,40 cm wide and 40 cms depth. I will do some reading regarding the enclosure design
Ah, thanks. One other thing I forgot to ask you is how much power your tripath amp can deliver into 4 ohms?
The reason I ask that, is that drivers that can reproduce low bass are often rather inefficient. You do get some reinforcement of the SPL by the room at the lowest frequencies, but you sometimes need several times more power to produce the same SPL as a midrange. Again, I am using generalizations here because I know you are not familiar with all the jargon and specs of drivers, loudspeakers, and audio.
There is a way to work around this - use a more efficient driver like a pro audio woofer. But these often can not reproduce low bass. That's because in designing them to be efficient the driver's response rolls off higher (Fs higher, Qts lower). Some pro audio woofers can reproduce low bass, but this often is only possible when you put them in a very large vented box, much larger than your 98 liters if you are planning to use a 15" woofer. Twice as large a box (and vented) could work, for instance.
There is also the possibility of boosting the power at the lowest frequencies or cutting the power at higher frequencies to flatten the response curve, for instance using a Linkwitz Transform circuit (you can create this with your miniDSP). But you will likely need several hundred watts of power to the woofer to do this.
If you just want to buy a driver, put it in your closed up u-frame, and be done with it I suggest that you look into a 12" woofer, which is much more suitable for this volume enclosure than a 15. Not a subwoofer, just a good quality woofer. For instance:
Peerless SLS 830669 - 12" Woofer
The above is a well designed and modestly priced driver that will work well in your box. Not super low bass but good clean bass down to 40 Hz. Reasonably efficient, so hundreds of watts are not needed. It is an 8 ohms driver, however, so your Tripath amp can only deliver about half as much power to it compared to a 4 ohm driver. Put stuffing in the box at 0.75 pounds per cubic foot.
If you can get a hold of (or already have) an amp that can deliver 250+ watts into 4 ohms cleanly, a really good driver for this sized sealed box is the Dayton UM12-22:
Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per Coil
Plays much lower than the Peerless above, and is an actual subwoofer with high output (Xmax) capability at low frequencies. But it's inefficient so you need more power to match the level of your other drivers.
Those are a couple of options from the myriad possibilities.
to get down to 30hz with a smallish sealed box, you need a woofer with low Fs, high xmax and able to handle high power (like those peerless and dayton units we are talking about). that automatically requires a sturdy cone. and a sturdy cone is heavy. check out the mms data.
the cone on those old sabas are <10gr. if you transition from such a light cone to a cone >200gr, there ought to be a difference in dynamic behavior and sound character.
hence your deltalite is actually a better match for your greencones.
that is why i suggested using existing deltalites in
either cardioid bass with stuffing your u frame
or a large vented cabinet lampizator p13 style
the cone on those old sabas are <10gr. if you transition from such a light cone to a cone >200gr, there ought to be a difference in dynamic behavior and sound character.
hence your deltalite is actually a better match for your greencones.
that is why i suggested using existing deltalites in
either cardioid bass with stuffing your u frame
or a large vented cabinet lampizator p13 style
I strongly suggest reading the MJK papers. Open Baffle is not a walk in the park, but is not as easy to mess up as sealed enclosures. OB bass can be amazing and apparently it gets better than what I've heard. (My friend built Slot Loaded baffles that are even more lush from what I've heard).
Built a quad of 18" Goldwood H Frames for my bass section. Foolishly I placed the baffle dead centre instead of moving it forward an inch. Initially I was worried, and they all reassured me over there, that the error wouldn't be a fatal one, and they were right. Now if making a traditional enclosure, this could have been much more of an issue.
FWIW, I have 2mm Xmax on my drivers, and get into the 20's with bass. The issue is that its not visceral, and I would be reluctant to EQ any as the physical limits of the driver will be reached, and that introduces all kinds of nasties when asking something to do something it doesn't want to do.
Built a quad of 18" Goldwood H Frames for my bass section. Foolishly I placed the baffle dead centre instead of moving it forward an inch. Initially I was worried, and they all reassured me over there, that the error wouldn't be a fatal one, and they were right. Now if making a traditional enclosure, this could have been much more of an issue.
FWIW, I have 2mm Xmax on my drivers, and get into the 20's with bass. The issue is that its not visceral, and I would be reluctant to EQ any as the physical limits of the driver will be reached, and that introduces all kinds of nasties when asking something to do something it doesn't want to do.
Hi, my latest project is the P17 in original crossover selection.
I found a Fane 15" that suites my hearing needs!
When seriuos listening I pull them forward and separate them 3m... I hear satisfying bass when pulled away from the back wall...
My amp is a single ended el84...
http://www.fane-international.com/downloads/Fane%20Sovereign%2015400%20DS030513.pdf
I found a Fane 15" that suites my hearing needs!
When seriuos listening I pull them forward and separate them 3m... I hear satisfying bass when pulled away from the back wall...
My amp is a single ended el84...
http://www.fane-international.com/downloads/Fane%20Sovereign%2015400%20DS030513.pdf
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your u frame is quite tall (70cm?)
if you close the back, it gives you 100-120 lt
i think that is a decent volume for vented box
add two front facing vents close to the floor and be done
ask for help re vent size and length from the forum
if you go sealed box, your system will be down 10-12db at 50hz roughly
if you close the back, it gives you 100-120 lt
i think that is a decent volume for vented box
add two front facing vents close to the floor and be done
ask for help re vent size and length from the forum
if you go sealed box, your system will be down 10-12db at 50hz roughly