Speaker cabinets

[pre65]

I have a pair of speaker cabinets that I purchased from Chris a long while ago.

I'm probably never going to use them so they are available at Owston for a charity donation.

Size is 230mm wide X 280mm deep X 330mm high.

Big hole is 140mm and small hole is 109mm and top port. They are lined and stuffed.

[andrew Ivimey]

They look rather nice but much too big for me 's true I still don't get decimal but two drivers a box is a bit radical.

[Toppsy]

Ah! I remember making these in 2012 for young Chris to take with him to UNI. BB Ply construction covered in Santos Rosewood veneer with a gloss finish.

For those interested here is the original thread started by Chris, that retails the original driver array and design concept. I do remember they had lots of good quality bass for the very small size of the cabinets. https://www.audio-talk.co.uk/phpBB3/vie ... php?t=4170

[Ray P]

Hmmm, I wonder if they could be modified with a new front baffle to use the little 4in full-rangers I have listed.

I'll check out the thread Colin has linked to for the dimensions and stick the info into an on-line cabinet calculator.

Colin, I guess you used 12mm ply?

[simon]

Do you have any parameters for those 4" drivers Ray? There didn't look to be much on the link you posted.

[Toppsy]

Hmmm, I wonder if they could be modified with a new front baffle to use the little 4in full-rangers I have listed.

I'll check out the thread Colin has linked to for the dimensions and stick the info into an on-line cabinet calculator.

Colin, I guess you used 12mm ply?

To be honest Ray, I can't remember and I only took photos of the finished cabinets. However, looking at my set of original uncompressed photos they appear to be MDF not ply and likely 12mm thick. Perhaps Philip can measure the thickness? Speakers of this small size will make no sonic difference whether they are in MDF or BB ply. The cabinets are very well braced for their size.

[Ray P]

Do you have any parameters for those 4" drivers Ray? There didn't look to be much on the link you posted.

Hi Simon, you need to click the 'Show More' button on the listing, then you'll see this;

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[Ray P]

To be honest Ray, I can't remember and I only took photos of the finished cabinets. However, looking at my set of original uncompressed photos they appear to be MDF not ply and likely 12mm thick. Perhaps Philip can measure the thickness? Speakers of this small size will make no sonic difference whether they are in MDF or BB ply. The cabinets are very well braced for their size.

Thanks Colin. A quick bit of maths and use of an online bass reflex design tool suggests that the cabinets aren't a bad match for the drivers - may have tme for a proper look later. I did try to do it in a rush earlier but realised I made a couple of errors in my haste.

[pre65]

15mm MDF by my measuring.

[chris661]

Ah, yes. I remember these. They were originally used with Fostex FE126E drivers covering >500Hz, and Tang Band W6-1139 mini-subwoofers below. Plenty of grunt down to about 40Hz.

The Fostex + mini-sub idea never worked particularly well for the variety of music that I enjoy, with the FE126 becoming quite strident at higher volumes. At sensible volume levels, though, it was good full-range reproduction in a fairly compact box.


We're all familiar with Colin's workmanship - they're beautifully finished.


Chris

[Ray P]

So, using the dimensions included in his listing by Phil and those in the diagram in the thread Colin linked, and asuming 15mm wall thickness, I calculate the total volume of a cabinet to be 15 litres. Subtracting the volume of the internal sealed enclosure leaves a volum of 11.1 litres. Putting the drive unit parameters (estimating SD and Xmax) and volumes into a Madisound bass reflex calculator gives the results below.

Not particularly 'scientific', playing around with the port diameter gives a port long enough to be routed through the internal sealed enclosure, so with the addition of a new baffle, glued to the existing one and sealing the exisiting port, the boxes could be turned upside down with the port on the front baffle, located below the 4in drive units with, apparently reasonable, if not earth-moving, results. How does that look to people?

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[simon]

I got the same result with the same webpage if that helps Ray, but that doesn't mean it's actually correct lol

[Ray P]

Yes Simon, but I guess it at least suggests it's in the right ballpark.

Without the internal sub-enclosure the 15 litre volume is much closer to the calculated response.

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[chris661]

IIRC, the port inside is extendable. I aimed for a 40Hz tuning, which gives a gentler knee and a bit more power handling down low.

Some other uses that I think might be fun:

- Super-compact 3-way. Put a waveguided tweeter in the big hole, SB65 for midrange in the smaller chamber.
- Conventional 6.5" 2-way.
- 3-way with a coaxial mid-high. Maybe pull a couple of Kef drivers?


Chris

[Ray P]

Thanks for the speaker cabinets Phil. I'll pop something into the British Heart Foundation a bit later.

Ray