I've been somewhat intrigued by the GRS 8FR-8 over on PE for quite some time now, I've almost bought a pair about six seperate times. It's a bicone wideband affair, looks pretty good despite the low price. I'm rather curious if anyone here has used them in a project. One of the customer photos has them in a Hedlund horn, seems like a pretty good speaker for horn loading since it's got a Qts of .4 with a decently low Fs of 39 Hz. And with the price of entry at $14.33 per driver, seems like just the thing to try a really cheap build with... Maybe pioneer an XPS Hedlund horn?
For those interested, here's the listing:
GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW
For those interested, here's the listing:
GRS 8FR-8 Full-Range 8" Speaker Pioneer Type B20FU20-51FW
Please read the 'product Q&A' responses to see how bogus the specs are; to say it's a B20 replacement is an insult to Pioneer.......
GM
GM
I did notice that question about parameters. Even so, the reviews are all positive. That question is also around seven years old now, so I'm wondering if manufacturing standards have changed. I've got some GRS 6 1/2" woofers in some floorstanders and they sound pretty decent. Maybe I'll take the hit and order two pairs to get the $11.46 price and send one of the pairs off to someone who can test them.
IME, 'bargain' drivers get worse over time as they continue to cheapen them up; the once popular RadioShack 'FR' drivers are prime examples and the BOFU too in that it had such a long run dating back to cheap AlNiCo motors driven with high output impedance tube systems that ideally required fairly low Qt drivers to [much] cheaper higher QT ferrite motors better suited for very low output impedance systems.
I've got several pairs, but our climate has dissolved all the surrounds, so unfortunately can't do any comparison and still not [re] set up to do any measurements. 🙁
BTW, some measurements seem to be missing from the Q&A, which are somewhat worse [~0.94 Qts], so definitely a good plan to measure yours. Regardless, none of the specs I've seen will technically work 'good enough' in existing BOFU designs without significantly more internal damping to make them ~aperiodic.
As to how they perform overall, T/S specs' impact on a speaker's sound peter out at the driver's upper mass corner [Fhm], so with high Qt drivers it will be limited to the mid-bass, ergo once the box is sufficiently damped its impact on the speaker's speech-up performance is minimal, so could in theory perform as well as or better overall than the BOFU, though based on its larger whizzer I'm betting it will require more tweaking to bring it up to par.
Regardless, at the price, worth checking out, so looking forward to what you wind up with/performance review.
Re Hedlund horn, Qts way too high for it, though suitable for a simple Klipsch 'Rebel' style corner horn.
Fhm = 2*Fs/Qts'
Qts' = Qts + any added series resistance: mh-audio.nl - Home
GM
I've got several pairs, but our climate has dissolved all the surrounds, so unfortunately can't do any comparison and still not [re] set up to do any measurements. 🙁
BTW, some measurements seem to be missing from the Q&A, which are somewhat worse [~0.94 Qts], so definitely a good plan to measure yours. Regardless, none of the specs I've seen will technically work 'good enough' in existing BOFU designs without significantly more internal damping to make them ~aperiodic.
As to how they perform overall, T/S specs' impact on a speaker's sound peter out at the driver's upper mass corner [Fhm], so with high Qt drivers it will be limited to the mid-bass, ergo once the box is sufficiently damped its impact on the speaker's speech-up performance is minimal, so could in theory perform as well as or better overall than the BOFU, though based on its larger whizzer I'm betting it will require more tweaking to bring it up to par.
Regardless, at the price, worth checking out, so looking forward to what you wind up with/performance review.
Re Hedlund horn, Qts way too high for it, though suitable for a simple Klipsch 'Rebel' style corner horn.
Fhm = 2*Fs/Qts'
Qts' = Qts + any added series resistance: mh-audio.nl - Home
GM
50 some years ago I had ~5 cubic foot reflex which converted to a short stubby horn vent that sounded pretty good in a corner with 6.5" "double magnet" whizzer fullrange sold by McGee Radio. GM - I'd like to see a sim of Oliver Read's high tuned BVR cabinets (not his "Fold A Flex")
here's Read's SAMS book
http://mirror.thelifeofkenneth.com/...production_of_Sound_Oliver_Read_1952_text.pdf
if qts were around like one reviewer said then hornresp says this BVR would have a bit of peaking
here's Read's SAMS book
http://mirror.thelifeofkenneth.com/...production_of_Sound_Oliver_Read_1952_text.pdf
if qts were around like one reviewer said then hornresp says this BVR would have a bit of peaking
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I'm about to move house, so I'm trying my best to resist buying new components, but if I decide to pick up a pair of these and do something with them I'll be sure to post results. Now that I know how easily builds can be prototyped in foam, I might be trying all sorts of new designs...
As far as being a drop in replacement for a BOFU, I'm not really concerned with that since I wouldn't be replacing a driver in an existing design but building a new enclosure from scratch.
As far as being a drop in replacement for a BOFU, I'm not really concerned with that since I wouldn't be replacing a driver in an existing design but building a new enclosure from scratch.
I'd imagine that GRS is a pretty good driver - especially if qts is around 0.7 or a bit under
ha - my random BVR looks reasonable with my M151 JBL
ha - my random BVR looks reasonable with my M151 JBL
Who needs a bass boost button when you've got peaky response? Aside from that, though, it actually doesn't look too bad. I'm assuming that graph represents the output from the vent? I've never used any sim software, so I'm really just guessing.
I've tried those GRS. And several other econo similar sized drivers.
I found the GRS to be disappointing. Sound like listening to a really cheap driver or something. Have a sound quality that would make you think you're listening to a cardboard cone or something.
Very similar that works better is the Goldwood GW8003. Still lacking for total final quality but much better than the GRS. Augment some brilliance from something else and you'd be ok. The Goldwood used to be very close in price to the GRS but has gone up. Maybe a reason why...?
If you want to be one and done, just do one of the Tang Band 8" drivers though!
EV3
I found the GRS to be disappointing. Sound like listening to a really cheap driver or something. Have a sound quality that would make you think you're listening to a cardboard cone or something.
Very similar that works better is the Goldwood GW8003. Still lacking for total final quality but much better than the GRS. Augment some brilliance from something else and you'd be ok. The Goldwood used to be very close in price to the GRS but has gone up. Maybe a reason why...?
If you want to be one and done, just do one of the Tang Band 8" drivers though!
EV3
I've looked at those Goldwoods, and they look like a tempting offer as well. As for the Tang Bands... My goal is always to make cheap drivers sound as good as possible. Of course the TBs will sound good, but they're $98 drivers, so when you wow your guests you can't tell them "I spent less than a hundred bucks on the whole system!" So, eventually, I'd like to get a pair of Tang Bands, or Fostex, or similar drivers, but for now cheap and good is the goal.
When Partsexpress introduced Visaton's BG20 into their lineup, it was only $23. Now its up to $31.64. It a reasonably good driver for the money.
I've thought about that one, as well. Response looks a little inconsistent over 8K, though, so I'm curious how it sounds. Have you personally used any of them?
Has anyone done any modelling for the BG20? Specifically, modelling for BVR or MLTL alignments. After looking around the web, it seems to be very well favored, but I can't find much information about it on here, just mentions of using it in potential future projects. As to the high end I was mentioning in the previous post, seems like the solution to that is a 4.5k notch filter, made for a very flat high end in the project I saw.
I've posted some, but don't have any of my old software, files, etc., loaded to post though google returned some builds, but don't remember if I did any of them: visaton bg20 diy - Google Search
GM
GM
Thanks! Not surprised, basically sounds like it looks then. Oh well, it's also advertised as 'engineered to withstand rigorous commercial use', so probably fine for cheap PA apps.
GM
Me too and many others back when the audio BBs and 'FR' forum
GM
Thanks! Been trying to remember/find it even before joining the net. This is the 'bible' my neighbor that did the DIY K15 relied on as well as helped me immensely in my formative years, especially the design criteria section of the RCA cab design [first? MLTL] I've posted about periodically.
Anyway, what page is this BVR cab on?
GM
GM, I had searched Google for diy designs with this driver and noticed there were quite a few BVR builds. I’ve never listened to one personally, but I really like the aesthetic of them. How would you characterize their sound?
Me too, bought a pair a couple of years ago. I share your disappointment. They just don't sound good and I didn't use them for more than a day. No bass and a raggedy midrange.
I like some of the other GrS drivers, but the 8" fullrange isn't even worth its cheap price. Too bad.
I guess the next question is which sim does the best job of simulating the most alignments? I mostly see people using hornresp, how does it compare to, say, akabak?
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