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I need a speaker (yes, only one) for a new system I'll be putting in place for a newly created space in my house. The speaker will be mostly used for background music but it looks like it will be the system we listen to the most. Requirements are: bookshelf (around 15 litres would be fine but could go for more if needed), high efficiency(94 dB/watt min), parts cost around $200 (ex cabinets). I would like it to play loud in a big room and we listen to all kinds of music.I'm considering Fostex Fe127e in the recommended bass reflex enclosure. Fostex FF225K and even the new FE206ES-R were considered but when modeled the graphs looked awful (I used the 46 liters recommended box for the 225K and it looks terrible, did I do something wrong?).
What other options do I have?
Thanks,
xavier
Follow Ups:
Well, 100 liters will buy you 100db/w/m and useable response to at least 30 hz if you go the Iron Law Breaker route:)
50 liters should get you the same efficiency and 40 hz.I erased the original post and am reposting it with this comment. I'm now planning to build a pair of 'proof of concept' 2cu ft bookshelf Iron Lawbreaker with 40 hz extension and 100db/w/m efficiency.
to your iron lawbreakers? have not found them.thanks,
Hi -I've mostly only discussed them to any extent in this forum. If you search the archives, you can probably find most of what I posted.
Today I was looking at Doc Bottlehead's site and saw he had a parts list for a high efficiency speaker to complement his S.E.X, a 2-watt amp/headphone amp.It is using Fostexs but I don't remember model no. & c. He does reference a cabinet from Parts Express and provides hook up instructions.
I used that volume as a reference because the Fe167e, which is one of my options as mentioned in the original post, seems to work (which is the recommended enclosure) so I don't find this as ridiculous as suggested. I also said I can go bigger.I am seriously considering the Fe207e recommended in this thread even though they require a larger volume.
A question on the Fe207e. Do they benefit much from the recommended supertweeter?
Thanks and keep those recommendations coming.
You mentioned high SPL as one of your requirements. That's tough for the Fostex units - they simply don't have much x-max. Once the bass excursions cause the voice coil to move beyond its linear travel, articulation takes a nose-dive.The 207E can displace roughly four times the volume of the 167E, so it can play 6 dB louder in the bass region before going non-linear.
You might try two FE207E's in a splayed array. In a 15 liter sealed box you should get ballpark 80 Hz extension assuming good boundary reinforcement. In a 30 liter vented enclosure you should get down to ballpark 60 Hz (again assuming good boundary reinforcement). Splaying the drivers will give you consistent tonal balance over a wide listening area, and don't worry about the supertweeter for now - the tonal balance will probably be better without it, as more highs would only emphasize the relative lack of bass. A 90-degree splay angle would be easy to do, but a 60-degree splay would probably be better. Connect the drivers in series.
Just my $.02,
Sounds cool! I could even use an independent amp for each driver since I was planning on using only one channel of a stereo amp. I don't have any experience with arrays though. Guess I'll have to put some time to learn! I might need to do some iterations to see how it works but sounds like a fun project.Thanks,
I designed a speaker very much like the one we're talking about here, but haven't gotten around to bulding it yet. It's a floor-stander intended to be placed right up against the wall, and I was going to call it the "Redneck Mother" after the Jerry Jeff Walker song ("well, it's up against the wall, redneck mother..."). The DCM Timewindows of yore also used a splayed array, but they weren't intended for against-the-wall placement.A horizontally splayed array would (as an example) have one Fostex aimed 30 degrees to the left of center, and the other aimed 30 degrees to the right of center. I'm not sure what would be the best angle to use - 30 degrees is just a guess derived from eyeballing the published curves. If you look at the middle (dotted line) curve at the link below, that's the 30 degee curve. From straight ahead, you'd be 30 degrees off-axis to both the left and right driver, so the outputs would sum and pull that 30 degree line up a bit. From on-axis of one driver, the other driver is 60 degrees off-axis (the bottommost published curve) so it reinforces in the lower octaves much more than in the upper ones. The net effect is to tilt the frequency response slightly downward as compared to the normal on-axis curve. This is an improvement, as the driver is a bit on the bright side otherwise.
The drawback is that, to either side of the centerline, the output from the farther driver is delayed in time relative to that of the near driver. This will introduce comb filter effects, or narrow-band peaks and dips in the response. The ear is pretty forgiving of comb filter effects - every sound you've ever heard in a room with a non-carpeted floor was comb-filtered by the floor bounce. If the goal was ultra high fidelity I probably wouldn't recommend a splayed array, but since the goal is good sound from a mono source across a large area it's what I'd do.
So now you have improved the tonal balance and are getting a fairly uniform response over a much wider area than you would have with a single driver. If it works, should be nice.
You can drive each Fostex with a separate amplifier channel, but make sure each is getting a MONO signal. You don't want the right channel to be way down in volume and lacking in highs from off to the left of the speaker, and vice versa.
Note that this speaker is definitely going to need boundary reinforcement to get much output south of 100 Hz.
I must admit that I still have slight reservations about the lack of energy above 10 kHz. Adding a top-octave enhancing tweeter to each splayed baffle (could be a much cheaper unit than the FT17H) might be worthwile, so I'd say leave room for the tweeters on the front baffle in case you want to add them later. Just be careful that the supertweeters don't brighten up the tonal balance too much - you want to cross over first order around 15 kHz (it will still be helping out some to about an octave below crossover). The idea is to just enhance a little without overdoing it, kind of like a few sprinkles on top of a cupcake.
Duke
I decided to rearrange amps and I'll be using more powerful ones so the high efficiency requirement does not longer apply. In consequence I'll start another thread at the diyaudio forum but looks like the redneck mothers is a way to go with different drivers (less efficient will allow me to use even smaller cabinets).Thanks a lot,
xavier
I'm linking the direction of the new thread.
Hi DukeInteresting. I was reading the CTS piezo pdf file,with splayed tweeters suggested.
I think its well worth trying,to hear the character.
Mike.e
There are three constants in life: death, taxes, and the inevitability of a (speaker)wire thread being closed -SY
You might still try the 167E. Provided it gets clean input, it can play quite loud in the recommended Fostex enclosure. It won't play low, however, so if you want bass, you'll probably want to add a powered sub.
http://www.zillaspeak.com/fostex207e.asphttp://www.zillaspeak.com/ZillaSpeakBoxPlotFostex168-167.asp
A super tweeter will be nice. I would use the $38 fostex.
I always prefer my fostex with a subwoofer.
If the SR version is real similar to the E,The E not SR version has very low Qts = meaning efficient operation but lack of low bass.With an xmax ~ 1mm I wouldnt be using these for subwoofers duty.
Mike.e
There are three constants in life: death, taxes, and the inevitability of a (speaker)wire thread being closed -SY
only 1/2 ft^3. Get real.
FE207E in a small BR cabinet (see link below). Bitchen.
all the best,
mrh
- http://db.audioasylum.com/cgi/m.mpl?forum=hug&n=66825&highlight=Fostex+mrh+Mark+Hardy&r=&session= (Open in New Window)
I very much like my pair of FE207E (rated 95dB) in vented cabs.
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