I know roughly what to expect, but that's never quite the same as the reality is it?
Should sound best at around a 12' distance with the speakers around 8-10' apart ,off axis(aimed at the listener at zero) around 15 degrees toed in with the 207. Will give actual position on drums and such.
ron
Should sound best at around a 12' distance with the speakers around 8-10' apart ,off axis(aimed at the listener at zero) around 15 degrees toed in with the 207. Will give actual position on drums and such.
ron
I was refering to speakers with an over-under mouth layout. Unless they are differentially tuned, or the mouth is curved so that they act as a single vent, the lower can potentially come in at a lower frequency than the upper due to the floor reflection boundary condition. So you don't get quite the precision LF image that some other boxes can provide unless something like the curve is added. That said, there are plenty of other advantages to the over-under layout to set that slight negative off against. Everything's a compromise.
I like to think of it as one fairly huge rectangular vertical cone. Besides combining the wavefronts the curve shapes the waveform to a more spherical shape by allowing a faster expansion at the center and a slightly slower expansion at the top and bottom. Ity simply corrects for the total aspect ratio of the mouth, which at lower frequencies is the W x H of the opening.
ron
ron
Hi guys,
Just a quick question about this driver for the "Chang".
I saw it via Zaph's site.
http://www.hemptonespeakers.com/Hemptone FR 8.pdf
Ian
Just a quick question about this driver for the "Chang".
I saw it via Zaph's site.
http://www.hemptonespeakers.com/Hemptone FR 8.pdf
Ian
Re: Is Curvy Chang suitable with F200A
Sorry for the late reply, I'm struggling to keep up with things at present as I'm deep within my thesis so not much time for audio.
The F200a? Now you're talking! Fostex themselves suggest a 45 litre box for it, ironically enough (same as for the 206), so we're really in business here. It looks like it goes into the box rather well, with a max-flat 1/2 space response to ~40Hz.
They'll sound completely different to Bob's (excellent) FTA-2000. The latter is a TL, & should have a nicely damped sound. This is a reflex cabinet with huge horn-loaded vents, so it will sound (much) bigger, though with similar delicacy -huge vents have their advantages compared to the small ports used in most reflex enclosures. Both are great, but are really aimed at different people / different uses, so whichever you favour really.
whallen said:
Sorry for the late reply, I'm struggling to keep up with things at present as I'm deep within my thesis so not much time for audio.
The F200a? Now you're talking! Fostex themselves suggest a 45 litre box for it, ironically enough (same as for the 206), so we're really in business here. It looks like it goes into the box rather well, with a max-flat 1/2 space response to ~40Hz.
They'll sound completely different to Bob's (excellent) FTA-2000. The latter is a TL, & should have a nicely damped sound. This is a reflex cabinet with huge horn-loaded vents, so it will sound (much) bigger, though with similar delicacy -huge vents have their advantages compared to the small ports used in most reflex enclosures. Both are great, but are really aimed at different people / different uses, so whichever you favour really.
Attachments
Well, Ron designed the curved front for the cabinet with the FE207E in mind I believe. In this case, the F200a and the FE207E have an almost identical response, so they should be a straight swap. Which is nice.
The curve should bring positive benefits over the regular flat-front version however, whatever the driver used (assuming it has a vaguely reasonable response); the effect will simply be lessened for other units as they aren't ideal for the enclosure in the first place.
The curve should bring positive benefits over the regular flat-front version however, whatever the driver used (assuming it has a vaguely reasonable response); the effect will simply be lessened for other units as they aren't ideal for the enclosure in the first place.
Hi, I reckon it is going to take at least another 2 weekends to finish the paint work, as I want to try and get a piano black finish for the sides etc, painting and colour sanding takes about 3 hours per cabinet, and that is a conservative estimate, there a lot of area to paint and sand! Plus she's not to keen on the Ironclad battleship look with the grey undercoat.
I am not allowed to put any drivers in the cabinets untill they are deemed finished by my beloved. My FE166's arrived just as I was starting to veneer thier cabinets, which accounts for the MDF sides.
Will be attacking the living room with a tape measure to check how near to optimal placement I can get them.
I am not allowed to put any drivers in the cabinets untill they are deemed finished by my beloved. My FE166's arrived just as I was starting to veneer thier cabinets, which accounts for the MDF sides.
Will be attacking the living room with a tape measure to check how near to optimal placement I can get them.
FlorianO said:
The original Chang was developed 1st for the 207 and adapted for the B20. As will most of the BVRs the big vents seem to really help broaden driver tolerence.
Ron added the curved front to optimize the shape of the sonic bubble leaving the box. Keys here were the tall height of the main baffle and the centred position of the driver.
So the Curvy Chang should just get better than the Chang with any driver that works in it.
dave
How much audible difference does the large opening of the Chang or Half Change make compared to a more typical port?
I keep thinking about building a Half Chang for a pair of B20s with the ability to upgrade to Fostex 207e later... does anyone know if the hole size and screw positions are the same for both drivers?
I keep thinking about building a Half Chang for a pair of B20s with the ability to upgrade to Fostex 207e later... does anyone know if the hole size and screw positions are the same for both drivers?
To use Harvey as an example, it's a massive difference. She doesn't sound like a reflex cabinet at all (despite the fact that she is one), but a very smooth BLH. You get a scale to the presentation that a small vent can't provide, and a complete absense of that God-awful thump many reflex boxes suffer from, primarily because the pressure at the front of the vent is considerably lower than it was at the start. The difference is not subtle.
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