I don't have any experience with the eminence. But with Fs at 35-40Hz and 4mm XMAX still doesn't seem like a great solution... I would recommend looking for something with closer to 12mm XMAX.... have a look at these:
Dayton IB385-8 15" Infinite Baffle Subwoofer | Parts-Express.com
In your case using electronic crossover you probably don't have to worry so much about the high QTS so perhaps these would be even better:
Dayton RSS390HF-4 15" Reference HF Subwoofer 4 Ohm | Parts-Express.com
Just ONE of these 15" with 12-14mm Xmax should produce at least 50% more output compared to 2 X 15" with only 4mm Xmax AND the Fs is closer to 20Hz which is almost a whole octave lower!
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This is because in an open baffle loudspeakers, there are design tradeoffs.
- Polar response
- Dipole cancellation
To obtain good polar response, relative baffle size needs to be slim compared to the driver diameter. But this sacrifies LF output. And vice versa if good LF output is desired, the baffle needs to be big but then the polar response is bad.
If you notice in JohnK's spreadsheet after the 1st hump the response is crappy. So the problem is transferred to the tweeter section. Ideally we want to avoid this and there are people like StigErik and JohnK who pushes the design further in the tweeter zone with Nao Note etc.
kalmi79:
You noted that you are using a "active DSP based crossover". That will mean you have some additional flexibility. If you go the passive route you'll need a high QTS woofer like the Alpha 15A as Martin King discusses here: http://www.quarter-wave.com/OBs/OB_Design.pdf.
Since you're going the active route you can use a low QTS woofer such as the Beta 15A or Dayton IB385-8 that sanedesign suggests. BUT you'll have to apply some significant bass boost (like 15 dB at 30 Hz) which can eat up much of the extra xmax capabilities these drivers may have. If you have the money you can get the best of both worlds with the AE Speakers Dipole 15 ($309.00 each!). Their IB15 is also an excellent choice at $149 each (but will need some bass boost in an OB).
However this is all theoretical since the only driver mentioned that I have any practical experience with is the Alpha 15A. I initially used it passively exactly as described in MJK's design linked above and am now using it with plate amps in a narrower baffle. I have MJK's MathCad worksheets and have only modeled the other drivers.
You noted that you are using a "active DSP based crossover". That will mean you have some additional flexibility. If you go the passive route you'll need a high QTS woofer like the Alpha 15A as Martin King discusses here: http://www.quarter-wave.com/OBs/OB_Design.pdf.
Since you're going the active route you can use a low QTS woofer such as the Beta 15A or Dayton IB385-8 that sanedesign suggests. BUT you'll have to apply some significant bass boost (like 15 dB at 30 Hz) which can eat up much of the extra xmax capabilities these drivers may have. If you have the money you can get the best of both worlds with the AE Speakers Dipole 15 ($309.00 each!). Their IB15 is also an excellent choice at $149 each (but will need some bass boost in an OB).
However this is all theoretical since the only driver mentioned that I have any practical experience with is the Alpha 15A. I initially used it passively exactly as described in MJK's design linked above and am now using it with plate amps in a narrower baffle. I have MJK's MathCad worksheets and have only modeled the other drivers.
While it is true that you will have to use some boost to achieve a flat frequency response into the lowest frequency range, the high vs low QTS should not make a difference on output capability at the lowest frequency... only XMAX is the limiting factor at the lowest frequency range.
Driver A - 15" and 12mm XMAX = X movement capability.... Driver B - 15" and 12mm XMAX also = X air movement capability. I see no logical reason why the driver QTS would have any effect on output capability when using an active setup.
With that out of the way, the IB15 does look like an excellent choice with 18.5mm XMAX. I'm sure the Dipole 15 would also be an excellent choice but at double the price, you might be more satisfied with double the number of Dayton drivers and henceforth double the output capability for nearly the same price.
Disclaimer: I have no experience with either of those drivers so I welcome any good/objective measurement data.
cheers,
Josh
Well I went the whole hog & bought the Dipole15, to go with the Neo 10 & 3.
I have also purchased MiniDSP to do the active side of life, now I have to work out how I'm going to amplify the speakers without putting me in the poor house & still getting the best sound possible.
David
Very exciting. 😀
You might consider these little amps for the smaller drivers.
Dayton DTA-100a Class-T Digital Amplifier 50 WPC | Parts-Express.com
On my existing Dual 10" H-frames I used this amp.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-812
If you want much more power you might consider this option:
http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=248-6562
I'm also thinking alot about the Neo10 and Neo3 pairing as well as subwoofer and amplifier choices. I started reading more about line arrays which lead me to find a very interesting ESL option:
NEW XPLS Series
I would be delighted to hear from you how things go with your project.
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Thank you for the suggestion, I will investigate them, how do they sound?
I have a Kingrex T amp that got rave reviws on 6Moons etc but in the end I preferred my Integra AB amp.
Currently I'm using the 6 @ ATA150 amps and they sound fine but perhaps not the best amp in the world for every driver/application. They are very affordable and so I don't hesitate to recommend them.
If you are building new speakers to replace your existing system, I would probably recommend you start with what you already have if you can. (i.e. your Integra and Kingrex stuff). Later you can decide if you think you need to upgrade or change something after you have the system tested and working. Any changes to amplifiers would likely provide much smaller improvements than would your new drivers, baffle and room treatments. Depending on your listening levels, the Integra could be perfectly satisfactory for your needs.
Regarding the DTA-100: I haven't heard this unit yet. I'm looking at other options because my existing ATA-150 _may_ not be the best option to drive the high end of my new speakers. It's a relatively cheap test but you already have the Kingrex T so this may not offer much for you because the DTA-100 looks pretty similar. Bottom line; I'm considering the possibly of using the DTA-100 for my tweeters but I'm not sure it will have enough power to keep me happy though. On the other hand, your Kingrex (or DTA-100) could be a good match for your tweeters because probably don't require much bunch of power relative to the other drivers.
Personally, I'm looking at building a second/entirely new system and I will be keeping the old system intact. I will need entirely new amplifiers and what I've learned from building my current system is that the ATA-150 doesn't have near as much power as the 10" subs can handle. I believe that more power and a higher dampening factor may be a limiting factor in the performance of my woofers thus my investigation into something like the EPQ2000 for subs. I may go with an EPQ450 for my new midrange drivers.
Hope this helps.
There will be soon, I'm just going crossed eyed drawing what I hope is the last design. I have been toiling away and reading lots & now think I know roughly what it will look like, as usual I'm making life hard for myself, build wise.
Once I finish the design I will put it up & see what the others think of my chances of getting good sound out of it.
The Dipole15's arrived yesterday so I have all of the speakers & I have the MiniDSP gear to do the Active crossover, but I warn you it will be a long time before they are finished & playing, I'm not rushing this build.
David
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Hi David,
why not build prototypes? too see how it performed? I m too interested to try the performance of DIPOLE15.
cheers
henry
why not build prototypes? too see how it performed? I m too interested to try the performance of DIPOLE15.
cheers
henry
I will build a prototype, but I need to know what the final design MIGHT be so I can test it in the prototype.
David
hi david,
which existing projects inspired you to do? i heard many enthusiast love their vintage (green) fullrange/mid.
cheers
henry
which existing projects inspired you to do? i heard many enthusiast love their vintage (green) fullrange/mid.
cheers
henry
I was originally inspired by Lukasz Frikus, hence I copied his P17 project.
My aim is to build a more aesthetically please, great sounding speaker that I designed from the ground up, albeit with lots of help from members of this forum, thanks everybody. My battle at the moment is the aesthetic bit & working it in with the OB design principles.
David
I Also built and use the Lampizator p17's with a RAAL Tweeter, Saba Mid and 18" BMS Bass (18N850v2)
So all I can offer is to vouch for BMS's quality they really do make a great speaker,
another perhaps even better consideration would be a Volt driver if you can find a supplier. Excellent quality and reputation and asthetically appealing. In fact Volt actually use some of the BMS stuff.
Did you make any tweaks to your p17? crossover and such?
or just kept it exactly as his design? I only ask because a few
people have mentioned this would work better with a modified cross over, but not tried it yet.
So all I can offer is to vouch for BMS's quality they really do make a great speaker,
another perhaps even better consideration would be a Volt driver if you can find a supplier. Excellent quality and reputation and asthetically appealing. In fact Volt actually use some of the BMS stuff.
Did you make any tweaks to your p17? crossover and such?
or just kept it exactly as his design? I only ask because a few
people have mentioned this would work better with a modified cross over, but not tried it yet.
I'd love to hear the RAAL Tweeter, but its out of my budget now. I have purchased the Dipole 15, & Neo10 & 3 for the new project.
No I didn't tweak the crossover as I don't know enough to touch a passive crossover, it's exactly as designed. The speakers don't measure that great but they certainly sound good to me & everyone that hears them, no audiophile's amongst the listeners though. I was going to run them with the MiniDSP but I'm too impatient and time poor for that, once I finished the new speakers, if they work out the P17 are up for sale.
I will use a set of 8" Saba's in some other speakers as they are too good to part with. I bought more than I needed, as always🙄
Lukasz obviously goes for simplicity in his crossovers and has spent a lot of time on them. I would imagine the people suggesting the changes (I have had the same suggestions) have not actually heard them with the changes, so it's all speculation.
It's funny, you get your first set of 15" any you think there massive but after a while you start thinking, I wonder what 18" would sound like and the 15" look small. It's the shipping that kills it for me though.
David
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Well my point still stands the people making the suggestions to change the crossover ( at least to me) don't know what the changes will sound like.
The crossover that Troels has shown for the P17 isn't the same as the original, as he has put resistors in?
Trying out Troels suggestions on the mid tweeter may be worth a go. One good thing is that his measurements of the speakers look very much like mine, which I'm happy about. The rise in the tweeter & the dip at about 6-7Khz is definitely worth trying to get rid of, although Aurality used a RAAL so that wont apply. I tried inverting the mid & have been listern to then like that but the jury's still out as I have an ear infection & everything sounds like crap.
My P17 don't model as badly as the plots he has shown, but as I said they don't model great either.
Once again, thanks for the link, very useful.
David
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