I don't build cabinets for a number of reasons. Let's face it, commercial cabinets are far better looking. So, I'm looking for a 20 litre cabinet to house my 8" sub and I stumble across a JVC that matches my decor.
The original specs for the system don't matter to me. I just want the box. However, I was astonished by JVC's claims: Frequency response: 30Hz - 20Khz. SPL 77dB. A mouse can fart louder than that.
I can only conclude that JVC are one of the few manufacturers telling the truth. i.e. at 30hz output is 10dB down. As quoted T/S parameters are + or - 30% what is the point of using them?
The original specs for the system don't matter to me. I just want the box. However, I was astonished by JVC's claims: Frequency response: 30Hz - 20Khz. SPL 77dB. A mouse can fart louder than that.
I can only conclude that JVC are one of the few manufacturers telling the truth. i.e. at 30hz output is 10dB down. As quoted T/S parameters are + or - 30% what is the point of using them?
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Not even remotely true, especially if you are willing to put in the effort, or say want to disguise a sub as an end table or ottoman etc.
Of course it's true. You are putting the cart before the horse. I've put a sub into an ottoman. The ottoman was exquisite, better than I could ever make. My input was the false bottom, two 8" drivers and a false bottom.
None of this is the point.
However, your comments have inspired me to create a new discussion. "How to build a subwoofer and stay married."
You missed the point, and only chose to read the second half. I don't really care what my speakers look like, but with a friend I have built some that are furniture grade. In a single car carport. I also built, with the same friend, a solid walnut guitar combo to match the period furniture in his living room so his SWMBO wouldn't b'ch about how his standard combo looked - he liked to come home after a long day and noodle on his guitar to whatever was on TV to wind down. Unless he opened the doors and showed you, you'd never have any idea what it was.
Similarly, you could make end tables to the couch to house your subs Louis XV style.
For L/R, veneering a rectangular cuboid box isn't particularly difficult, nor are many other shapes. Smooth finish and prep and take it to an automotive spray painter and have them painted in any one of a bajillion colours. Again, not difficult, just time consuming. There are lots and lots of ways to finish, most of which are not offered by commercial manufacturers. Vinyl or CF wraps of a psychedelic design of your choosing? Simples. Stained black hardwood baffle with the rest painted to match your minimalist furniture? Sure.
By and large, I think most commercial speakers are as special as McDonalds, even if the workmanship is superb.
Better still, pick a wife where you don't have to Prince Harry your scrotum.
My late wife would never have told me I couldn't have my speakers in the living room for 2 reasons. First, it was important to me, and second, no speakers, no huge guitar rack. I would have moved it to the shed.
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Depends on your woodworking skills. I've seen very beautiful DIY loudspeaker boxes, but the few that I built were not beautiful at all.
Even if they are, +/- 30 % is still more accurate than having no clue at all. If you can measure them accurately yourself, that's of course better.
I have had a quick websearch and found no data on the volume of a mouse fart.
Have you any definitive data that a mouse fart can exceed 77db or is this yet another example of untrustworty data? However I was able to acertain that miice can fart.
The majority of comercial data on speakers seems to be untrusworthy whith peak SPL being arrived at by multiplication of the efficiency and peak power with no accounting of any losses -compression or non liearity of the driver.
This situation seems to arrive from specification oneupmanship where if one maufactuer claims a figure then another has to find a way to match it.
Have you any definitive data that a mouse fart can exceed 77db or is this yet another example of untrustworty data? However I was able to acertain that miice can fart.
The majority of comercial data on speakers seems to be untrusworthy whith peak SPL being arrived at by multiplication of the efficiency and peak power with no accounting of any losses -compression or non liearity of the driver.
This situation seems to arrive from specification oneupmanship where if one maufactuer claims a figure then another has to find a way to match it.
I've been pointing this out for years and been told I don't know what I'm talking about. Then I'll find a speaker where I know the exact bass driver, cab volume and tuning and be able to show it can't produce X SPL because the LF driver runs out of excursion too soon for the simple multiplication to apply. Then factor in the BS 'peak power' of +3dB to make it worse. It's harder with MF and HF drivers to do the same, but not always impossible.
I know this doesn't factor in suspension non linearities, but almost always they'll restrict excursion in passband.
JVC SP-NXF4BW . . .
As I said, I'm not bothered. I'll throw out the 6.5" and replace it with a Tannoy 8" driver that I have lying around. What bothers me is the blatant lies, and the fact that enthusiasts are comfortable modelling on these lies. Yes, the sub may well respond to 30Hz but that is likely -10db.
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I've built quite a lot of speaker boxes over the years, all modelled in either winISD or hornRESP.
All but two builds measured very close to the modelled response, good enough for me. (The other 2 just needed the ports trimmed down slightly to raise tuning a bit and lose a dip in the response just above tuning frequency)
How do you know you need a 20 litre box for your Tannoy driver unless you have measured its TS specs yourself, or are using the manufacturers TS specs ?
Your JVC box is ported, you can model the box with new driver and probably find the port mach will be way too high with the bigger VD of the Tannoy.
Rob.
All but two builds measured very close to the modelled response, good enough for me. (The other 2 just needed the ports trimmed down slightly to raise tuning a bit and lose a dip in the response just above tuning frequency)
How do you know you need a 20 litre box for your Tannoy driver unless you have measured its TS specs yourself, or are using the manufacturers TS specs ?
Your JVC box is ported, you can model the box with new driver and probably find the port mach will be way too high with the bigger VD of the Tannoy.
Rob.
^^ As have I Rob, but mainly with Unibox. I never assume thye port calcs tune correctly. I build, measure and adjust, which is one of the reasons I prefer tubes for ports as they're easier to trim or extend than slots.
Erm . . . the Tannoy driver came out of a 19 litre box - close enough. Of the three components, the port is the most easily adjustable.
Fair enough, but I'd still want to model the Tannoy in the new box. You cannot be sure that the JVC box is tuned correctly for the Tannoy driver.
Rob
Rob
Hmmm... a 6.5" driver with a 150W drive and 77dB sensitivity; that means a peak output in decibels in the high 90s. I would have thought that was quite respectable for such a tiny driver with its commensurate limited volume displacement.
JVC NX F4BB F3_NX F7_B User Manual LVT1833 003C
JVC NX F4BB F3_NX F7_B User Manual LVT1833 003C
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Interesting point but there's really no need. The port is the most easily adjustable component. It's not a full range system It's a subwoofer operating within a comparatively narrow bandwidth. Tuning to 40hz will give me more rumble, 55hz will offer more boom.
I'd expect a lot more from a 20 litre cabinet, at least 85dB. Consider, the JVC requires 150w to produce the same volume the Tannoy can manage with just 20.
30% tolerance ??
I thought many used 10% tolerance.
30% I would guess means they dont reject drivers.
I cant tell from the pictures but it looks like computer speaker.
sitting at a desk 77 dB sounds somewhat useable.
but otherwise really poor for room listening
I thought many used 10% tolerance.
30% I would guess means they dont reject drivers.
I cant tell from the pictures but it looks like computer speaker.
sitting at a desk 77 dB sounds somewhat useable.
but otherwise really poor for room listening
It's not a computer speaker. Apparently it comes from a fairly good Home Theatre System JVC NX-F7 SOPHISTI 2.1 Home Cinema System Review | Trusted ReviewsI totally disagree with reviewer (probably because we had differing test set-ups). I can see how the sub would overpower the small satellites. But paired with Sony SS-NX1s they produced smooth, warm bass. However, this where the 77dB became problematic. They are giving away around 10dB the Sonys. The bass was nice but there just wasn't enough of it.
All of this is moot as I've just sold the 8" Tannoy driver I was going to use the cabinet for.
I enjoy being a scrap merchant. It's a 20 litre cabinet. I've still got the spikes from the Tannoy box sitting on my desk. Maybe I can fit another downward firing 6.5" driver in the base? I've only got a Peerless kicking around at the moment.
The cabinet is pretty. I'll see what tomorrow brings.
All of this is moot as I've just sold the 8" Tannoy driver I was going to use the cabinet for.
I enjoy being a scrap merchant. It's a 20 litre cabinet. I've still got the spikes from the Tannoy box sitting on my desk. Maybe I can fit another downward firing 6.5" driver in the base? I've only got a Peerless kicking around at the moment.
The cabinet is pretty. I'll see what tomorrow brings.