st_eloi,
Found this pic of the insides and bracing of Chrisb's Pensil 7.
https://www.diyaudio.com/forums/ful...ar-alpair-bvr-construction-7.html#post4841924
Found this pic of the insides and bracing of Chrisb's Pensil 7.
https://www.diyaudio.com/forums/ful...ar-alpair-bvr-construction-7.html#post4841924
Hi, I have a pair Alpair 7.3 and I'm planning to make a Pensil enclosures because I don't have enough and proper place for FH3.
Аlso was wonder if there is need to increase internal volume of the cabinets because of the additional bracing.
I guess that is best to keep the internal volume close to the plans as far as possible.
Does it matter in which direction (in width or in deep) will increase the box size to keep the original internal volume ?
I assume that these stripes / narrow bases for mounting the back have been taken into account in the calculations and there is no need to add their volume to the whole internal volume.
Аlso was wonder if there is need to increase internal volume of the cabinets because of the additional bracing.
I guess that is best to keep the internal volume close to the plans as far as possible.
Does it matter in which direction (in width or in deep) will increase the box size to keep the original internal volume ?
I assume that these stripes / narrow bases for mounting the back have been taken into account in the calculations and there is no need to add their volume to the whole internal volume.
Not sure if you are willing to try something outside of MA and Fostex but there are a lot of other drivers out there.
Sounds like you want a slightly more forward presentation but not famous Fostex shout.
You might like the FR88EX or the Dayton PS95-8. I would put them in a FAST with a woofer below 900Hz or even 600Hz. You can use sealed or vented woofer alignment but I would go sealed if you want to use your sub. The full range can have a small sealed rear chamber about 1.5L to 2L volume. If you want to follow a plan or recipe for the cabinet/driver/crossover look for the 10F/RS225 FAST thread. Substitute the Scan 10F with the FR88EX or PS95. Adjust the R1 resistor to taste to trim the level of “forwardness and engagement”. I suspect you will enjoy the PS95-8. Give it a try - they are not expensive.
For the woofer, you will need an RS225-8. It’s specially suited for this speaker and if you pick another, you are on your own with the crossover.
The sound of this speaker has been universally praised by many builders and even compared against much bigger and more expensive speakers. More information here:
10F/8424 & RS225-8 FAST / WAW Ref Monitor
More info on what FR88EX sounds like here:
A Subjective Blind Comparison of 2in to 3.5in drivers - Round 5
More info on what the PS95-8 sound like here:
A Subjective Blind Comparison of 3in to 5in Full Range Drivers
Sound clips included.
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Too late... a pair of Alpair 7a are en route. What I really need to do is build these boxes and listen to some records instead of obsessing about hifi.
Thanks for the suggestion - I know there are lots of drivers out there but it's another rabbit hole I need to avoid. Likewise multi-ways, crossovers etc. The simplicity of full range really appeals to me, as does the ease and price of construction. It's bad enough deciding on one driver and one cabinet, let alone several drivers and hundreds of cross-over choices!
While we're on it though, what is FAST? I've seen it around but haven't found an explanation.
Thanks for the suggestion - I know there are lots of drivers out there but it's another rabbit hole I need to avoid. Likewise multi-ways, crossovers etc. The simplicity of full range really appeals to me, as does the ease and price of construction. It's bad enough deciding on one driver and one cabinet, let alone several drivers and hundreds of cross-over choices!
While we're on it though, what is FAST? I've seen it around but haven't found an explanation.
Isn't too late
You can combine A7.3 with RS225 and I think the result will be even better in comparisson with the 3 "drivers.
These Alpair are great drivers.
I also tend just to build boxes and listen to background music instead of obsessing about hifi but the FAST / WAW option looks very tempting
Thank you Scott!
You can combine A7.3 with RS225 and I think the result will be even better in comparisson with the 3 "drivers.
These Alpair are great drivers.
I also tend just to build boxes and listen to background music instead of obsessing about hifi but the FAST / WAW option looks very tempting
Thank you Scott!
It's an acronym for the daft phrase (no reflection on X or anyone else: it's widely used) 'Fullrange And Subwoofer Technology'. Because, as we all know, subwoofers are 'technology' and no other type of drive unit is. And of course, as we also all know, when a fullrange driver is partnered with an LF unit, that LF unit is always a subwoofer. Except when it isn't.
The even clunkier, but arguably more accurate phrase of 'Fullrange ASsisTed' is sometimes substituted. Translation: it's a 2-way loudspeaker. They usually, though not invariably, have crossover frequencies lower than most current 2-ways (but similar to many traditional 2-ways) because the wideband driver can handle it. Here's a commercial example I was responsible designer (within the company requirements) for: Markaudio-Sota Viotti One standmount loudspeaker | Hi-Fi+ In this particular case, the crossover frequency is actually relatively 'normal' by current standards as it was targeting a number of acoustic goals I don't have time to go into here.
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The main advantage is that it lets the full range driver do its magic best, and that is playing the circa 500Hz to 5kHz "telephone" band with a point source that is all in phase and time aligned (because there is only one driver). This gives us the beautiful imaging, sound stage, and feeling of realism that we love about full range single driver speakers. It removes the need for the little fullrange from having to go deep in bass where distortion is high and lets the woofer handle that. But since there is a woofer, it provides much nicer lower distortion bass that just isn't possible with a small full range driver.
Yes, even the A7a can be used as the "tops" in a FAST. The XO is very simple and preserves the transient perfect nature of a single driver by using a first order XO:
Here is the measured response and you can see despite the handover from the woofer (red) to the fullrange (green), the phase remains relatively flat as if they were working together as a single driver:
Here is the 1st order XO:
Btw, I have also heard FAST means "Fullrange Assisted Sub-woofer Technology"
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Eschewing the F.A.S.T moniker, others have long promoted the TLA (three letter abbreviation) WAW, which I prefer to enunciate as Woofer Assisted Wideband to avoid any additional confusing verbiage.
Just repeat after me kiddies; 2-way with lower XO than “normal” - which does restrict the choice of HF drivers to something with wider bandwidth and power handling than your garden variety dome or ribbon tweeter.I think the historians amongst us would say that there ain’t nothing new here either - other than novel ways to achieve the XO and other EQ tricks via DSP - just the cute acronym.
Just repeat after me kiddies; 2-way with lower XO than “normal” - which does restrict the choice of HF drivers to something with wider bandwidth and power handling than your garden variety dome or ribbon tweeter.I think the historians amongst us would say that there ain’t nothing new here either - other than novel ways to achieve the XO and other EQ tricks via DSP - just the cute acronym.
Also called WAW (wooffer assisted Wideband) — because many think FAST if daft.
Basically adding a helper woofer to a FR used as midTweeter, XO typically in the 200 to 450 Hz.
Here is the example i am currently listening to (with A7.3 (=A7A) — built by chrisb:
A growing area of interest with lots of room for experiementation and many potential implementations.
dave
It is just starting to gain traction again thou. The oldest WAW i have encountered was a pair of Noresco with a Foster FE83A and an 8” Foster woofer with huge alnico magnets. This dates it to the early 60s.
dave
That they are, and rightly so. You could also argue (and I tend to) that the old Altec gear with the compression mid-tweets crossed low (as in 800Hz or lower) fell into the same category.
Not sure how we could describe the aforementioned Viottis though since both drivers are wideband units and they're not crossed low.
Not sure how we could describe the aforementioned Viottis though since both drivers are wideband units and they're not crossed low.
Yes. Some XOed as low as 500 Hz. The trend to waveguide loaded tweeters with XOs pushing down to 1Khz also follow as an example of the same kind of thinking — ie if we can push the XO lower we have less issues with XOs and that the drivers are physically in a different place. If the distance cam be lowered such that the driver centre-to-centre is smaller than a 1/4 wavelength at the XO frequency those issues (mostly) go away, removing many issues that XOs bring..
dave
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