I'll just quote raymondj since we are turning the page...
Further digging, because I am interested in this sort of problem myself, throws up two rear enclosures:
Boutique Haut-parleurs & Audio DIY
Visaton AK 10.13 Mid-Range Driver Enclosure – Impact Audio
The £5 Beyma VM 30 (Available at Blue Aran) is apparently 116mm internal diameter and 1.2l. Looks plastic.
The £14 Visaton AK 10.13 Mid-Range Driver Enclosure (Available from Impact Audio) is 115mm interior diameter and 0.8l. Looks metal.
Closed back drivers (and closed back cone tweeters) always have an hump in output at low frequency. This is because the enclosure is really too small for the driver. How fixable that might be remains to be seen. I think the simple trick is to cross above the humpy region. Might get me simulator running... 🙂
raymondj said:
Further digging, because I am interested in this sort of problem myself, throws up two rear enclosures:
Boutique Haut-parleurs & Audio DIY
Visaton AK 10.13 Mid-Range Driver Enclosure – Impact Audio
The £5 Beyma VM 30 (Available at Blue Aran) is apparently 116mm internal diameter and 1.2l. Looks plastic.
The £14 Visaton AK 10.13 Mid-Range Driver Enclosure (Available from Impact Audio) is 115mm interior diameter and 0.8l. Looks metal.
Closed back drivers (and closed back cone tweeters) always have an hump in output at low frequency. This is because the enclosure is really too small for the driver. How fixable that might be remains to be seen. I think the simple trick is to cross above the humpy region. Might get me simulator running... 🙂
The things System7 shows are very pricey. I’d go into the buck-or-two and find a suitableplastic dish to glue to the back of the baffle.
dave
dave
I don't think 2X £5 will break the bank, Dave... 😀
But I have found ANOTHER closed back. The Visaton M10. It's a 102mm width but rectangular, so doable on a 100mm cutout IMO.
M 10 - 8 Ohm | Visaton
Visaton M 10 - 8 Ohm – Impact Audio
What's good about this one is you can model it in Visaton Boxsim, though the optimiser doesn't work in v1.3 for this one last time I looked.
Claims to be 90dB 1W/1m, but nearer 86dB IMO. But the mid filter may lift it.
The Visaton AK 10.13 enclosure is also useful as a study guide:
AK 10.13 | Visaton
The Starlet design which incorporates it uses much the same filter topology as David's Magnum K2 speaker.
Sorry to be so wordy, but an interesting problem needs some thought.
But I have found ANOTHER closed back. The Visaton M10. It's a 102mm width but rectangular, so doable on a 100mm cutout IMO.
M 10 - 8 Ohm | Visaton
Visaton M 10 - 8 Ohm – Impact Audio
What's good about this one is you can model it in Visaton Boxsim, though the optimiser doesn't work in v1.3 for this one last time I looked.
Claims to be 90dB 1W/1m, but nearer 86dB IMO. But the mid filter may lift it.
The Visaton AK 10.13 enclosure is also useful as a study guide:
AK 10.13 | Visaton
The Starlet design which incorporates it uses much the same filter topology as David's Magnum K2 speaker.
Sorry to be so wordy, but an interesting problem needs some thought.
Wow. Thank you all so much for the replies and suggestions for drivers and enclosures and the general advice and pointers.
I have put the information into a spreadsheet and attached it. I have left out the GRS units because the UK price seems to high.
I have a couple of questions:
1. What are the pros/cons of a dedicated mid over full range? Is a full range unit preferred?
2. The MA Alpairs have a lower sensitivity than say the Faitals.. am I not aiming for a higher sensitivity or was this only for mids and not applicable to full range?
3. What does WAW mean? Did google it, but I find many odd definitions that obviously don’t relate to audio.
PVC tube out the back or the cab? Like a vent? Or you mean on the back of the driver as in enclosure? Sorry if this is a dumb question!
Thanks, will PM 🙂
Marvellous and rewarding would be ideal. I think the Alpair and the Faital are serious candidates.
I have put the information into a spreadsheet and attached it. I have left out the GRS units because the UK price seems to high.
I have a couple of questions:
1. What are the pros/cons of a dedicated mid over full range? Is a full range unit preferred?
2. The MA Alpairs have a lower sensitivity than say the Faitals.. am I not aiming for a higher sensitivity or was this only for mids and not applicable to full range?
3. What does WAW mean? Did google it, but I find many odd definitions that obviously don’t relate to audio.
PVC tube out the back or the cab? Like a vent? Or you mean on the back of the driver as in enclosure? Sorry if this is a dumb question!
Thanks, will PM 🙂
Marvellous and rewarding would be ideal. I think the Alpair and the Faital are serious candidates.
Attachments
No XO with the FR, you get teh seemlessness of a good FR (if you choose a good one). The tweeter above a mid might do top better.
The Faital Pro (at least the 3”) have an optimistic sensitivity rating. You want the woofer typically to be 3-4 dB more sensitive than the woofer (and use an XO point base don the BS(-3))
Woofer Assisted Wideband. Historicallty called a FAST.
No, it is a transmission line damped until it is aperiodic (or close). Flattens the impedance (making a passive XO easier) and if done right means no time smear coming back thru the cone.
dave
Brilliant thanks for the explanations.
I’ve just been double checking the dimensions and I’ve hit a snag. The diameter of the Alpair 5.3 is ~10cm, and I’ve screwed up because there’s a small area at the bottom of the cut out, it takes the diameter at that point to ~11cm. Must have had a brain fart when I measured that, because I didn’t even think about the additional cutout at the bottom. This is probably going to be an issue for any gaskets etc. I’ve wrongly assumed the Alpair would have a slightly larger surround.
I also measured the distance between screw holes (just purely because they’re into chipboard and already quite close to the edge) and the distance is ~12cm.
Is there a larger equivalent to the Alpair 5? Thinking it’s probably going to be easier to increase the cutout than fill holes etc. The Alpair 6.2 would still fit in the existing cutout but the surround is 11.3 diameter. Would probably still have to fill that cutout at the bottom though. Is the Alpair 6.2 still a worthy look?
I’ve just been double checking the dimensions and I’ve hit a snag. The diameter of the Alpair 5.3 is ~10cm, and I’ve screwed up because there’s a small area at the bottom of the cut out, it takes the diameter at that point to ~11cm. Must have had a brain fart when I measured that, because I didn’t even think about the additional cutout at the bottom. This is probably going to be an issue for any gaskets etc. I’ve wrongly assumed the Alpair would have a slightly larger surround.
I also measured the distance between screw holes (just purely because they’re into chipboard and already quite close to the edge) and the distance is ~12cm.
Is there a larger equivalent to the Alpair 5? Thinking it’s probably going to be easier to increase the cutout than fill holes etc. The Alpair 6.2 would still fit in the existing cutout but the surround is 11.3 diameter. Would probably still have to fill that cutout at the bottom though. Is the Alpair 6.2 still a worthy look?
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KJF still has A6.2m.
Alpair 6M full range driver | KJF Audio
Any bigger and the eclosure will need to get bigger.
dave
Alpair 6M full range driver | KJF Audio
Any bigger and the eclosure will need to get bigger.
dave
If the 6.2 is the limit for the cabinet, will it sound worse than the 5.3?
At a push I could try and decrease the cutout size but it would probably be time consuming.
What would you do?
At a push I could try and decrease the cutout size but it would probably be time consuming.
What would you do?
the A6.2m and A5.2/3 sound very similar. The larger driver will pay a little louder and can go lower (not that that should be needed). A gretaly underappreciated driver in the line-up
dave
dave
Ok thanks.
Do you happen to know of a buck-or-two alternative to HiFi35 foam? £20 to cover 2 speaker grilles seems like a lot. Found plenty of 35PPI foam (I’m assuming that’s what the 35 in it means?) for use in aquatics, but it’s too thick.
Do you happen to know of a buck-or-two alternative to HiFi35 foam? £20 to cover 2 speaker grilles seems like a lot. Found plenty of 35PPI foam (I’m assuming that’s what the 35 in it means?) for use in aquatics, but it’s too thick.
Yes, like this: Grille Foam
The original construction of these grilles appears to be ~6mm composite wood board with cutouts for the drivers, onto which a layer of grey foam was glued to cover it and then cut out so only the mesh was in the way of the drivers. See attached image.
I’ve been given some really nice vintage style grille cloth but it’s got quite a large weave and my plan was to have the foam cover the cut outs in the board to give less transparency to the cloth.
I was just wondering if you had any ideas for cheap acoustically transparent foam? 🙂
The original construction of these grilles appears to be ~6mm composite wood board with cutouts for the drivers, onto which a layer of grey foam was glued to cover it and then cut out so only the mesh was in the way of the drivers. See attached image.
I’ve been given some really nice vintage style grille cloth but it’s got quite a large weave and my plan was to have the foam cover the cut outs in the board to give less transparency to the cloth.
I was just wondering if you had any ideas for cheap acoustically transparent foam? 🙂
Attachments
Acoustically transparent foam designed for speaker fronts doesn't come cheap.
And you'll want it to be thin for your application.
Lots of foams are 10/15mm, but this one is 5mm:
Adam Hall 019505 Speaker Front Foam 5mm – Thomann UK
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Wilmslow Audio have a few grille components:
Grille Covering and Pre-covered Grille Frames
You don't need acoustic foam with most grilles since it is often hardboard and foam with cutouts and a covering cloth. Affixed with velcro or studs. Presumably something like bicycle tube rubber cement to secure. Dunno.
More pressing is a replacemant mid. Tweeter shouldn't be an issue.
I had a complete disaster modelling the Visaton M10, and the Monacor closed back looks as awkward. I am guessing the crossover resembles the two affixed images with a more regular midbass. You might investigate.
Apropos nothing , here's a few similar projects for ideas.
SEAS 503:
SEAS Kit 503
Wharfedale E70:
Tandberg HiFi15:
No, the Tandberg circuit didn't help either with closed back. Maybe the old closed backs were flatter.
The 4" Faital Pro 4FE32 does the right things IMO, but presents mounting problems on a 10 cm cutout. The Beyma VM30 enclosure at 116mm and 1.2L should be OK.
Faital Pro : Faital Pro 4FE32 8 Ohm Faston :: PS19.62 IN STOCK (20 Jul 2021)
The 5" Faital Pro 5FE120 looks easier, but might need a proper enclosure with a VAS of 5L.
Faital Pro : Faital Pro 5FE120 8 Ohm Faston :: PS20.28 IN STOCK (20 Jul 2021)
Problem here being, and some people don't seem to get it, is this is a loud 93dB speaker with a 12" bass. The fix is not easy on a slim budget.
This SEAS MCA15RCY would probably work, but eye-watering price around £70 and needs enclosure:
H1262-08 MCA15RCY
What you could do is entirely revamp it with new drivers and a more sophisticated crossover. Just using the cabinet really.
Grille Covering and Pre-covered Grille Frames
You don't need acoustic foam with most grilles since it is often hardboard and foam with cutouts and a covering cloth. Affixed with velcro or studs. Presumably something like bicycle tube rubber cement to secure. Dunno.
More pressing is a replacemant mid. Tweeter shouldn't be an issue.
I had a complete disaster modelling the Visaton M10, and the Monacor closed back looks as awkward. I am guessing the crossover resembles the two affixed images with a more regular midbass. You might investigate.
Apropos nothing , here's a few similar projects for ideas.
SEAS 503:
SEAS Kit 503
Wharfedale E70:
Tandberg HiFi15:
No, the Tandberg circuit didn't help either with closed back. Maybe the old closed backs were flatter.
The 4" Faital Pro 4FE32 does the right things IMO, but presents mounting problems on a 10 cm cutout. The Beyma VM30 enclosure at 116mm and 1.2L should be OK.
Faital Pro : Faital Pro 4FE32 8 Ohm Faston :: PS19.62 IN STOCK (20 Jul 2021)
The 5" Faital Pro 5FE120 looks easier, but might need a proper enclosure with a VAS of 5L.
Faital Pro : Faital Pro 5FE120 8 Ohm Faston :: PS20.28 IN STOCK (20 Jul 2021)
Problem here being, and some people don't seem to get it, is this is a loud 93dB speaker with a 12" bass. The fix is not easy on a slim budget.
This SEAS MCA15RCY would probably work, but eye-watering price around £70 and needs enclosure:
H1262-08 MCA15RCY
What you could do is entirely revamp it with new drivers and a more sophisticated crossover. Just using the cabinet really.
Attachments
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Ok, so maybe the simplest thing to do would be to decrease the cutout size.
On the theme of “free and cheap”: Placing some paper behind the cutout and tracing it would give me the exact size and shape then liquid nails some replacement chipboard into the cutout. Again all materials being from the shed. After completely curing (not difficult or long winded right now in the UK!) I could easily cut the new appropriate size. After it’s been sprayed black I doubt it would even show.
Assuming the cut out is indeed decreased how does the modelling work for the Alpair 5.3 or the Faital 4FE32?
I think I’ve found some better mesh for the grilles so that any old foam will not show behind it. This’ll make using a cheap medium density 5mm foam from eBay easy as I will follow the original design and cut out the foam too.
The crossover appears to consist of just 3 caps and 3 coils, the image you attached has a resistor? I don’t see that on the boards I have. There is an image of it earlier in this thread, but I have attached again. The cap values are 5uF, 5uF and 10uF but it looks like one of them is in series so values could be 5uF, 10uF and 15uF. If remaking the crossover is preferable, I can definitely do that.
On the theme of “free and cheap”: Placing some paper behind the cutout and tracing it would give me the exact size and shape then liquid nails some replacement chipboard into the cutout. Again all materials being from the shed. After completely curing (not difficult or long winded right now in the UK!) I could easily cut the new appropriate size. After it’s been sprayed black I doubt it would even show.
Assuming the cut out is indeed decreased how does the modelling work for the Alpair 5.3 or the Faital 4FE32?
I think I’ve found some better mesh for the grilles so that any old foam will not show behind it. This’ll make using a cheap medium density 5mm foam from eBay easy as I will follow the original design and cut out the foam too.
The crossover appears to consist of just 3 caps and 3 coils, the image you attached has a resistor? I don’t see that on the boards I have. There is an image of it earlier in this thread, but I have attached again. The cap values are 5uF, 5uF and 10uF but it looks like one of them is in series so values could be 5uF, 10uF and 15uF. If remaking the crossover is preferable, I can definitely do that.
Attachments
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I noticed there were 3 capacitors and three coils and no resistors. Rearrange those 6 into a well known crossover. 😀
I am struggling to find a readable frequency response plot for these Goodmans Magnum K2 speakers without registering with Goodmans.
But my understanding is they are 96dB at 2W, or 93dB at 1 W. That's a lot, but unexceptional for a 12" bass. I think we can write off the regular fullrangers.
I wouldn't go below 89dB for a mid and 90dB for a tweeter. 4dB down on the mid is usually the most difference that works in a 3 way.
Regular 4" and 5" mids and midbasses won't hack it here, being around 86dB.
The Faital Pro's seem to hack it.
I found a couple of candidates in the Visaton Range too:
Fullrange Systems | Visaton
The 92dB Visaton R 10 ND 8 might be perfect with the Beyma enclosure:
R 10 ND - 8 Ohm | Visaton
The 90dB Visaton SC 13 looks much more robust but needs bigger cutout, which may or may not be a good thing.
SC 13 - 8 Ohm | Visaton
No idea on availability.
I am struggling to find a readable frequency response plot for these Goodmans Magnum K2 speakers without registering with Goodmans.
But my understanding is they are 96dB at 2W, or 93dB at 1 W. That's a lot, but unexceptional for a 12" bass. I think we can write off the regular fullrangers.
I wouldn't go below 89dB for a mid and 90dB for a tweeter. 4dB down on the mid is usually the most difference that works in a 3 way.
Regular 4" and 5" mids and midbasses won't hack it here, being around 86dB.
The Faital Pro's seem to hack it.
I found a couple of candidates in the Visaton Range too:
Fullrange Systems | Visaton
The 92dB Visaton R 10 ND 8 might be perfect with the Beyma enclosure:
R 10 ND - 8 Ohm | Visaton
The 90dB Visaton SC 13 looks much more robust but needs bigger cutout, which may or may not be a good thing.
SC 13 - 8 Ohm | Visaton
No idea on availability.
Steve, lacking in knowledge in this area, I just had to find out more.
Sometimes the experts take for granted that their audience understands what they are saying, so I think it is worth sharing my new knowledge with david83:
I had been working on the principle that, if the midrange proves too sensitive, it can always be padded down. This stemmed from david83's requirement for the midrange not to be swamped by the bass, as he is presently experiencing.
However, the technically correct method is to choose a midrange with a smaller sensitivity than the woofer. (Apparently, this offsets the bandpass gain from the crossover and the baffle reinforcement of the midrange output relative to the woofer - all a tad technical for the uninitiated!).
The question is, how much less sensitive should the midrange be compared to the woofer?
Steve's suggestion of 4dB is a reasonable estimate. I read that the figure could be anywhere between 1dB to 6dB depending on the actual 3-way system in question.
There you go, I'm learning all the time! 😎