I personally failed to get my 2500.4 to play in a closed volume. I tried with 40 and with 70 liter nice boxes. When I heard them in 20 liters with the phase inverter recommended by the site, I immediately knew that the attempts with the closed box were in vain. So I can advise you to put it in 20 liters, but with a bass reflex. Don't worry about problems - mine work in a 35m² room and at maximum levels the membranes don't move. You have to touch them with your hand to know they work. So the bass reflex is not loaded at all. These are amazing drivers - make them sturdy boxes with LOTS of fins inside - they will thank you! Good luck !!🙂
Curious; how did they 'fail'? In what regard did they not perform to expectations?
I remember at first they couldn't get down to 100 hertz to cross them with the subwoofer and I think the level was also lower than my mids (scan speak 12mu) which are 90db... Hope this helps. ..
Thanks, that clarifies a lot. I'd have used them ported though I think it would be difficult to get a sufficient port in (not modelled, guesstimated) or even better, used an 18" below them and used them as mids say 300-1k2. I used similarish specced JBL2123 this way for ages, either MT or MTM.
Volt provide box size and port dimensions for two or three possible sizes of box for their bass drivers. In this case I think they are coming from lots of experience on what actually works.
The given cross over figures may need some measurements to fully verify their suitability, but again they are a useful starting point.
The given cross over figures may need some measurements to fully verify their suitability, but again they are a useful starting point.
Thanks, how were you using the BM2500.4, as a mid-bass?
I was thinking of going sealed and then using EQ on the FA123 to boost the bass a bit, along with room gain as they will most likely be placed near the rear walls.
The BM2500.4 do model quite nicely in a 24 Litre box tuned to 65Hz (with heavy fill & 2x 67mm x 140mm ports https://wilmslowaudio.co.uk/reflex-ports/67mm-flanged-port) .
Only thought was power handling, but with two per side, I think it was hitting excursion @ 20Hz at 95dB (112dB input level) which should not be an issue in a home setting!
I use mine in a 20 liter net volume with a 90mm long and 75mm diameter bass reflex. The crossover is active, 24db with 100-150 hertz below (I use the crossover on the receiver) and 700 hertz above. Underneath is running a Volt RV3143 in 85L with the factory recommended bass inverter and I hope that after a lot of testing and tweaking (very problematic room with huge peaks and troughs) we have managed to achieve a remarkable result.. Lately I can't stop listening to the 3 albums to Brian Bromberg with Akira Jimbo (unfortunately for the neighbors 🙂) I hope things work out for you too...!
I also trusted the Volumes and phase inverters recommended by Volt and I think I was not wrong. A friend of mine bought (after hearing mine) an RV3143, but he wanted a box calculated with Bassbox pro, (different bass reflex) but the end result was not good and we had to modify the bass reflex to the dimensions recommended by Volt..
I use a first row...
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Thanks, I'd just worked that out 🙂
I guess Volt bass drivers in ported cabs does make sense, I used a Kord Tornado and Vulcan (obscure 80s British Monitors) that both used a older BM220DS driver, and the Tornado in a ported cab sounded a lot better but then at that time, I did not have a sub to try and extend the bass.
We are In the process of moving house so between packing, spent a little time attempting to clean the Volt bass driver. Used a bit of rolled up tape first to try and remove more of the dust, not really effective. So bit the bullet and got a small dish with a little warm water and a dash of fairy liquid, and with a sponge applied a little to a small area first and lightly pulled it across the cone and surround. Seemed to work quite well so let it dry to see if it made a negative difference. After a while, it was fine so continued on going just using some kitchen paper roll so it would fall apart and collect the dust, lightly vacuumed up and then carried on between a sponge and microfibre cloth.
Has come out quite well I think, I’ll leave it a while again and try a little more later. I've left the other three drivers still with the grilles on for the moment, until we have moved next week just to avoid any damage when packing them up.
Before
After
Has come out quite well I think, I’ll leave it a while again and try a little more later. I've left the other three drivers still with the grilles on for the moment, until we have moved next week just to avoid any damage when packing them up.
Before
After
I fired up the CAD with some ideas on a ported enclosure, based around the ~20 litres suggested, this is a ~40 litres/pair uing two flared ports (67mm x 140m)
The idea behind the vertical braces are to go up against the rear of the magnet but allowing airflow behind for the vented rear of the drivers. I like the idea of raising them up and porting out the bottom to avoid any issues when placing near the rear walls. This idea puts the tweeter level around 65cm I think.
Please excuse the basic models for the Volt/Seos, just a quick knock up in my work break!
V2 Plan by Robert Seymour, on Flickr
V2 Pair 1 by Robert Seymour, on Flickr
The idea behind the vertical braces are to go up against the rear of the magnet but allowing airflow behind for the vented rear of the drivers. I like the idea of raising them up and porting out the bottom to avoid any issues when placing near the rear walls. This idea puts the tweeter level around 65cm I think.
Please excuse the basic models for the Volt/Seos, just a quick knock up in my work break!
V2 Plan by Robert Seymour, on Flickr
V2 Pair 1 by Robert Seymour, on Flickr