SLOB project

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Ali Tait
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#76 Re: SLOB project

Post by Ali Tait »

Yes 200hz, my mistake.

Thanks Mark would be useful info.
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rowuk
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#77 Re: SLOB project

Post by rowuk »

There is a variation on this theme called RIPOLE. Details at WWW.Ridtahler.de. Other Ripole posts also recommend drivers and filtering. I have built some and they work in spite of the dramatically reduced footprint.
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JohnG
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#78 Re: SLOB project

Post by JohnG »

The Ripole is a Bass design that I got interested in when I was initially planning a Sub for the the 57's.
It got my attention as it gives of a similar figure of eight wave length as does the ESL.
It was looking relatively easy to produce the conventional vertical mounted support structure for the drivers.
After various readings, I also discovered there is a lay flat version that carries the same Ripole name.
It would take a little bit of a search to find this version, I think I was translating the article from French.
I would be more than willing to attempt a Ripole for my OB Bass Section.
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Ray P
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#79 Re: SLOB project

Post by Ray P »

JohnG wrote: Mon Dec 23, 2019 6:00 pm ...I also discovered there is a lay flat version that carries the same Ripole name.
That's essentially what the SLOB has, just without the name.
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Ray P
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#80 Re: SLOB project

Post by Ray P »

Following up on the Nelson Pass active crossover, yesterday I installed Micro-Cap and downloaded the file that defines the Linkwitz LXMini filters, for which this crossover was originally developed. Just played around with changing values in the LXMini filters to explore the software a little and it seems easy to use (as a GUI) so further exploring and reading (about filter design) required. In addition to lo/hi pass filters the crossover can be configured to perform some equalisation too; the LXMini filter has a little bass boost and a notch in the mid/treble.

With this approach I would use MiniSP to explore the required filter settings and then try to replicate them in Micro-Cap to derive the component values to build the active crossover.
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Ray P
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#81 Re: SLOB project

Post by Ray P »

So, I think I've got a good way to have removable baffle panels. My concern was around having bolts or screws into the side of the birch ply as it's not where the ply is particularly strong and I can see the bolts coming loose or pulling out. I think the solution is to use barrel nuts;

Image

but I'm going to make some with a larger diameter (20mm) from some whale brand tufnol rod I have - tufnol can be tapped with a thread and is mechanically strong but will also look nicer set into the birch ply.
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IslandPink
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#82 Re: SLOB project

Post by IslandPink »

I used M5 stegosaurus nuts into the edge of my 18mm ply, Ray. This isn't their proper name, but if you search stegosaurus, you should find a pic or two on my thread to show what I mean !
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Ray P
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#83 Re: SLOB project

Post by Ray P »

IslandPink wrote: Thu Dec 26, 2019 11:56 am I used M5 stegosaurus nuts into the edge of my 18mm ply, Ray. This isn't their proper name, but if you search stegosaurus, you should find a pic or two on my thread to show what I mean !
I considered those Mark; they're good when screwed into the face of birch ply but never found them very satisfactory into the edge as I've found they tend to chew/splinter the layers.
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IslandPink
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#84 Re: SLOB project

Post by IslandPink »

I drilled sizeable pilot holes, then epoxied them into place. However it was not easy to get them placed exactly where I wanted. I think your method will be fine. I got some nice stainless countersunk allen-key M5 bolts so they looked nice on the perspex.
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Ray P
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#85 Re: SLOB project

Post by Ray P »

IslandPink wrote: Thu Dec 26, 2019 2:54 pm I drilled sizeable pilot holes, then epoxied them into place. However it was not easy to get them placed exactly where I wanted. I think your method will be fine. I got some nice stainless countersunk allen-key M5 bolts so they looked nice on the perspex.
Yes, my over-sized barrel nuts will spread the load into the ply nicely and some nice stainless steel bolts is just what I plan to use. I'll build a jig so the bolt holes will be positioned correctly and are perpendicular to the side panel.
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pre65
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#86 Re: SLOB project

Post by pre65 »

JohnG wrote: Mon Dec 23, 2019 6:00 pm
The Ripole is a Bass design that I got interested in when I was initially planning a Sub for the the 57's.
The 18" speakers I got some while ago came in a ripole design cabinet.

TBH when I played them on their own the sound was not to my liking. Perhaps they needed 500W of pro amp to wake them up ?
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rowuk
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#87 Re: SLOB project

Post by rowuk »

There is a lot that manufacturers can screw up on drivers. One of the biggest killers of Sound is a voice coil that can handle 500 watts. With the possibility of over 100dB/watt/meter, how much power would really be necessary at home? 20 watts?
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#88 Re: SLOB project

Post by IslandPink »

Well this is one of my observations from years of experimenting with drivers in various projects. I am convinced low-Rms drivers ( which are usually low-power drivers ) are the key to getting coherent and realistic sound at HiFi levels in normal rooms.
When Nick came round to mine in November, he commented late in the day, after a lot of listening, that my speakers filled the room with sound at low playing levels. I have deliberately chosen bass and mid speakers with Rms less than 0.7 , and I am happy with the results I have had with this approach.
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Ray P
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#89 Re: SLOB project

Post by Ray P »

IslandPink wrote: Thu Dec 26, 2019 5:55 pm ...I have deliberately chosen bass and mid speakers with Rms less than 0.7...
Hopefully this isn't a really dumb question but I don't understand your reference to rms and the value of 0.7

I understand RMS as root mean square and relevant to the sustained power input a speaker can tolerate and I know peak power /0.717 enables you to derive the RMS value. I also know the Thiele & Small parameters include several 'ms values.

Can you help me out please.
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#90 Re: SLOB project

Post by Cressy Snr »

Rms is the resistance that the driver suspension presents to whatever is trying to move the cone; a sort of mechanical version of ‘Ohms’ This means in mechanical terms, the ‘lossiness’ of the driver suspension. Rms, mainly influences the Qms parameter.
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