I have the non HD version and I think it's OK for the 20-? Hz frequencies but nothing extending into the midrange. My dilemma, and the reason for the ?, is how far to dial up the DSP in frequency and what cutoff I'd use to fill in for the Fast-15's lack of low bass. Right now I have one forward firing 10" JBL sub in front and two 8" downward firing subs (a Klipsch and and Onkyo--this was a stone soup experiment) on the other two walls of a C shaped room that is open on the right hand side of the listener. The subs are wired in series and all get the same signal from a bridged 250 W class A/B amp--a 90's Acurus A250 modified to dual mono that's a total beast. Signal to the subs from the mDSP cuts off at 65hz with a 24 dB/octave Linkwitz-Riley filter, with all settings ~ optimized using Omnimic. The preamp for the sub amp and the main amp (First Watt F5 clone) is a DIY Nelson Pass Korg NuTube design with dual outputs. The mains have nothing in circuit in terms of tone control or anything else, and I want to keep this existing setup, just with a higher cutoff for the swarm subs. I can change cutoff point, filter shape, and levels, but also play with the parametric eq in the mDSP if needed, and use the Omnimic to verify the room response as before. I tuned into this thread to get insights on whether that's a fool's errand or not before ordering the drivers. Maybe the holes in the response are too hard to fill, and turning up the subs that far in frequency and maybe volume would make the subs "visible." If that happened I'd probably sell my failed project and move on.
In this chain the mDSP 2X4 is the weak link, but when I bought it I was thinking/hoping that for bass I would not hear the difference. Thanks @waxx, your statements support keeping the mDSP out of the main system.
One thing I picked up reading a thread on the Decware forum is that these Lii Audio drivers may have an extremely long break in time. Making it always a bit of a crap shoot to know whether or not they would work in your system. And with your amplifiers--I'm not pursuing the flea watt tube amp approach like they are and have not drank that flavor of KoolAid (yet--never say never).
In this chain the mDSP 2X4 is the weak link, but when I bought it I was thinking/hoping that for bass I would not hear the difference. Thanks @waxx, your statements support keeping the mDSP out of the main system.
One thing I picked up reading a thread on the Decware forum is that these Lii Audio drivers may have an extremely long break in time. Making it always a bit of a crap shoot to know whether or not they would work in your system. And with your amplifiers--I'm not pursuing the flea watt tube amp approach like they are and have not drank that flavor of KoolAid (yet--never say never).
I dont think so, but you have to put some faith into what you've read about them in terms of how they sound. As they'd be up at 65 Hz and above, I'm pretty sure they'll be handling most of the program material. As to locating 65 Hz on down, that should be a hearing capability independent of whatever speaker is on top. This would be something the mDSP HP outputs could help you verify. At least get that concern out of the way before ordering.
I'm only replying because I had my Lee F15s naturally rolling of on or about that value (Ok, higher as an attempt to avoid as much IM as possible) on an OB. I built wings around the F15 to push the perceptible low end response down some, then changed my mind on the IM concern, leaving the wings in place as baffle weights / stiffeners. I may be crossing 80-100 now; but I've got a helper 18" on the same baffle, versus a sub swarm, so I can get away with it due to the proximity of the crossed to woofer.
I think it's perfectly fine to let the FR speakers roll off naturally (i.e. not electrically or digitally crossed) via whatever box or baffle; bring up the subs or "woofer" to match both level and frequency rolloff electronically via DSP. You did mention flea-power, so the control provided by envelope cabinetry for high power handling situations probably isnt an issue.
Does anybody think that the shape of the baffle matters? Is it better for bass if the bottom that supports the baffle is a solid, full piece of wood? This may not be a good idea, but I'm considering making baffles sized similar to the football shaped or square Caintuck audio baffles, using a larger board for the base of them, and screwing that to them on the sand filled stands I use for my regular speakers, about 24" high. Again, this would be used with a swarm sub. What are the up and downsides of this? This is largely because of real world considerations-keeping the drivers off the floor to safeguard them from my dogs!
Well, yes. Any speaker driver needs something to push against and mass / weight about the periphery of the frame is suitable. You can also add that to the magnet structure, by bringing it in solid mechanical contact with a large mass of some kind, if it's not possible to provide that at the frame (bolt pattern).
Number two is the wrap distance from the front of the cone to the back. Ideally that's infinite (like the mass...) but practical trade offs must be made in realizable speaker designs. The so called "H frame" is one design that bests a plain flat baffle, by folding it into a more compact form. But it presents its own problems, one of which is you have to cross well below the cavity resonance created by the "H" ends.
Each and every design has its own problem set. Some are solved more easily than others. Some are solved simply with enough money, others with a different sort of cost; application of inginuity, skill, time and effort.
This is my tentative plan but I haven't started yet. Listening to the speakers on the floor for a while convinced me that having the speakers at ear level and perpendicular to the ground is essential in my room to get the best imaging-the sweet spot is very narrow. I have the swarm sub to fill in the bass holes without making that obvious (hopefully). So far I am happy with the quickness and tone but they definitely need break in and sound like crap with some songs!
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Does anybody have any feedback on this Decware product to smooth out the bump at 5k that apparently happens with the Fast 15?
Description of Fast 15 bump at 5k
Decware Fast 15 Network
Description of Fast 15 bump at 5k
Decware Fast 15 Network
Re: the product linked to above to smooth out the Fast-15 response, I wish somebody so much smarter than me would work out values of the components that would plug into a network that might tame the Fast-15's response even more effectively. As covered for some more stodgy and smaller full rangers in this article. You may have heard of this author elsewhere on this site. And I hear he has commented favorably on Lii speakers in the past (can't remember if it was Lii Song or Lii Audio and now cannot find the page).
https://www.firstwatt.com/pdf/art_cs_amps.pdf
Wonder if this is worth starting a new thread?
https://www.firstwatt.com/pdf/art_cs_amps.pdf
Wonder if this is worth starting a new thread?
Hello, hello, hello, is there anybody in there? Sorry, bad audiophile music joke but I'm not sure if anybody is still following this thread. I have had some thick baffles made from five sheets of 1/2"stacked BB--I did not have the scale of tools to tackle this. The cutout for the speaker has a rounded edge that has a 3/4" perpendiculat profile on the back side and is rounded on the front--it was the best they could do with the bits and equipment they had and I could not afford to buy (or locate) a custom bit. The driver edge for the Lii Audio Fast-15 is 1/2" deep including the gasket material on the front edge. If it were routed in to be flush mounted and the remaining perpendicular edge next to the driver on the front edge of the baffle were 1/4" would this have any audible effects? My wishful thinking is that the whizzer relies on the main cone for a "waveguide" and the lower frequencies would not have a problem with this perpendicular edge. I could sink it in 1/4" further so sound waves only encountered rounded edges but I'm concerned that this would leave insufficient purchase for the mounting screws. If anybody that reads this has feedback please let me know.
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Sorry to be unclear, I"m just wondering: if the speaker is backmounted and inset so the half inch rim of the speaker is flush with the back of the baffle, will the part of the edge closest to the driver, which is perpendicular to the driver for 1/4" before starting to round over, cause diffraction problems with higher frequencies? When I've heard this discussed it's always in the context of a back mounted tweeter not a full range speaker with a whizzer cone. I'm not sure this concern applies to my situation.
Thanks for that calculation GM. This is a full range large diameter driver with a shallow cone and an absurdly large whizzer that has the typical ragged response and peaks. I can use DSP and mic the room to figure out how to make it work as good as I can but...given all this does the edge we're talking about even move the needle? I hope that eigenmodes are lost in the mix because creating the taper you suggest is beyond the capacity of the cabinet shop I'm working with. Thanks again for your input!
@Sinisterexaggerator
You're welcome!
Understood and it does, but as NP alluded, the round over swamps them overall, i.e. was just showing you to 'think' in frequency size when looking for sonic issues to decide what's more/most important.
You're welcome!
Understood and it does, but as NP alluded, the round over swamps them overall, i.e. was just showing you to 'think' in frequency size when looking for sonic issues to decide what's more/most important.