BMS 4592ND-MID versus the B&C DCM50 Update

[Rudy81]

Greg, glad to see you ran the test again. What is the retail price of the B&C drivers?

[greg928gts]

Greg, glad to see you ran the test again. What is the retail price of the B&C drivers?

I don't know if there is such a thing as retail. I saw a price on the internet for $368 each, which is pretty reasonable considering what the lowest dealer cost is for them. What I mean is, the dealer isn't making a lot on them at that price.

FYI - if you want to play around with the 300Hz crossover point, it would better if you had a mid horn with a Fc lower than 300Hz.

BTW - I disagree with Al about his theory on a lower crossover point between the midrange and the woofer for the Khorn. Now that I'm able to try infinite numbers of crossover points and slopes with the Behringer setup, it's obvious to me that the frequencies between 160Hz and 400Hz would sound better coming from a dedicated mid-bass driver/horn than from the big folded bass horn of the Khorn. Of course adding a mid-bass cabinet to the Khorn is impractical for most people, but lowering the crossover point and changing the proportion of sound energy from the bass bin to the mid-horn is a step in the right direction, and it certainly sounds better to my ears. I tried the BMS/V-Trac as low as 250Hz with no bad effects, although it's at that point that I could hear the driver really starting to work hard, so that's as low as I went. Not that it was a problem, I just got a little nervous at that point, thinking about popping a diaphragm.

I've been talking to a BMS engineer over in Germany about crossing lower than 300Hz with the 4592 and "boiling it down", he says it's not a problem if the driver is well matched to the horn. This would take some work on my part to design and build a horn that coupled that closely with the 4592 to get lower than 300Hz, and I'm not prepared to do that right now. But certainly 300Hz with a 12db slope is not an issue for the 4592.

I wish I had Mike Lindsey's Khorns back here right now, I'd love to compare the enclosed bass bins to mine with this test gear I've got now. I'd like to see if his bass bins reproduce mid-bass better than mine. That was my impression when I had them here.

What a tool this Behringer setup is! I have to thank Dave H for pushing me to get this. I'm able to really fine tune the filters just for the V-Trac/BMS on Khorns, and hopefully be able to convert that information to passive networks. We'll see! I'm having fun with it.

Greg

[Rudy81]

Thanks Greg. Yep, the DCX is a really cool tool...that's why my ALK Universals are on eBay, I'm sold on the active setup. The other option BTW, is to find a bass bin that will cross higher than the Khorn bass bin....say the Jubilee bass bin. I would love to try that with my top hat setup and see how that sounds. Actually, a Jub bass bin clone might be the least expensive way to go.

I do know the one thing I liked about your Vtrac was that 'open' sound that it has. For now I'm very happy with my active Khorns, but I know the crossover between the bass bin and the mid is a bit under supported by both drivers.

[greg928gts]

Thanks Greg. Yep, the DCX is a really cool tool...that's why my ALK Universals are on eBay, I'm sold on the active setup. The other option BTW, is to find a bass bin that will cross higher than the Khorn bass bin....say the Jubilee bass bin. I would love to try that with my top hat setup and see how that sounds. Actually, a Jub bass bin clone might be the least expensive way to go.

I do know the one thing I liked about your Vtrac was that 'open' sound that it has. For now I'm very happy with my active Khorns, but I know the crossover between the bass bin and the mid is a bit under supported by both drivers.

I need to do more listening, but right now my thoughts are that I haven't been completely satisfied with the sound of mid-bass coming from any of the large folded horn bass bins that I own, regardless of how high the bass bin might work. I'm not saying Jubilees don't work to produce mid-bass, it's just that I think I would prefer the sound quality of the mid-bass more if it was coming from a dedicated mid-bass horn, or even a large mid horn. I'm inclined to want to leave the large folded bins working below 160Hz or 200Hz.

One of the things I notice with the Khorn bass bin, the Jubilee bass bin, and the Jamboree bass bin, is that all three tend to be louder through the mid-bass than the deep bass. Which means that if you want to "voice" the speaker through attenuation, either actively or passively, when you proportionally turn up the bass bin, by turning down the mids and highs, you are always going to get more mid-bass than low bass. If the system was built so that the bass bin only handled low bass, then attenuating the mids and highs down would leave a boost in low bass. I don't know if I explained that as clearly as I'm thinking it, but hopefully you get my gist.

Of course, those who tend to like active crossovers, also don't mind a little EQ mixed in, and that might be just the ticket to smooth out mid-bass humps in any of these folded horns. I guess I'm still in the passive/natural/simple mode!

I'm working on a filter for the mid/woofer in my V-Trac Khorns that will smooth out the mid-bass, and part of that filter includes dropping the crossover point to 300Hz. I'm able to do that with the Fc260 horn and BMS 4592. From what I'm hearing so far, this is going to be an improvement over the 400Hz first-order filter I've been using. The end result, I hope, is that I'll be able to voice the Khorn for a boost in low-bass, something I've wanted in my own system for quite some time.

Greg

[Rudy81]

I know exactly what you mean about the response of the bass bins. However, I find the same to be true of mid and hi drivers as well. No driver I have messed with has a totally flat response. In my case, I used two EQ points on the Khorn bass bin to get a relatively flat response. This is one of the nice features of going active. In my particular case, even before going active Audyssey would try to equalize any large response issues anyway, so I generally have a rather flat system in my room. My room is also heavily treated, so I no longer have huge issues with any particular frequency band.

Going active has allowed me to play with the crossover points to find a spot that gives me the smoothest transition. It has also allowed me to EQ the drivers independantly in order to reduce the amount of changes Audyssey needs to make to achieve the reference FR.

On my plots, however, I can clearly see that the bass bin is rolling off and the mid is just starting ot get going. There is not comfortable overlap that fully covers that 400 Hz to 450 Hz band. I am trying to fill that gap. I could go back to the K55, but I have found I like the smoothness of the JBL much better. Vocals, in particular, clearly demonstrate the superiority of the JBL drivers. The K55 has a tremendous ability to cover a very broad frequency range, but it does not have the quality I found in the JBL.