Sealed Crossfiring 6x10 build

[kringle77]

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[kringle77]

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[kringle77]

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[rodl2005]

Wow! Looks cool! Total newb question......whats the attenuator control for? Mid/hi freq??

 

[kringle77]

Ok, here is the knee jerk, pre-gig review. I played broke this cab in a bit by playing outdoors, out in the woods for 2.5 hours straight. I used my Genz Benz SM9.2 with flat eg and slowly increased the volume and low end. At first, the cab responded exactly how I expected. Sounded great but, was alittle light on the bottom end and just alittle congested from about 200hz to 800hz. After 1.5 hours and increased volume I actually forgot that I wasn't playing my NV610. The betas started to loosen a bit. At the end of 2.5 hours I was running my Genz up to where the clip light was blinking regularly and the cab sounded great. The lows extended and the midrange cleared up. It pretty much sounded like my berg. Actually, the lows up through to about 1khz is exactly the same. The stock Betas naturally have just alittle more of a peak at around 3khz than the bergs when firing straight forward (this may be because the bergs are more broken in though) When crossfired, the sound evens out more and sounds smoother. I compared the two cabs sided by side when I got home at low volume. Pretty much the same sound with the 8" mids turned off. I noticed something that I had expected. With the straight firing berg, the drivers have a certain growl at aroung 800hz-1khz that Im sure is those frequencies adding in front of the cab. The LDS was maybe alittle smoother in that range because of the crossfire. The frequency combing was less. Probably just less additive. The average person probably wouldn't hear the difference and you won't hear it at a gig. With my face about a foot in front of the grill the sound was super bright and agressive but smoothed off from 3' on out. With the berg it is as you would expect, bright directly in front of the cab then losing highs as you move in the horizontal plain.

Outdoors I actually prefered the cab with the mids turned off but, I think that I noticed the same thing when using the berg with an external mid. Indoors, I think that I will be glad the 8's are there. Especially with people standing right in front of my cab, as they always tend to do.

This cab sounds exactly like I had hoped and I have no regrets. Don did and amazing job as usual. Would I change anything? We'll see. Im wondering if I should have used maybe less of a crossfire angle. I may have been better off to use 155 degrees instead of 135. I also may have done well to just go for the 8x10 version which could be made in the same size cab and then have the option of using a pair of the new Beta 10 sealed back mids. (which were released after the cab was already built. ) If I play some gigs and these things actually matter indoors, I may have Done build me an 8x10 version in the same size cab and re-use the drivers and hardware.

So, I'll report back after some gigs and stay tuned for any design changes. Let me say again, this cab is a winner all the way and I have no regrets. The build, sound, looks, dispersion, weight, ease of movement are all an upgrade to a stock sealed cab. And please, no digs are needed because I am constantly tweaking. I have no kids or expensive toys and Im good with my money so, I can afford to tinker with my gear.

 

[kringle77]

One thing I'd like to stress is that if anyone uses these beta drivers, they take awhile to break in and sound right for a bass rig, or any cab. It took me 2.5 hours at louder volumes than I would ever used at a gig to just start to break them in. It would probably take 10 gigs at my regular volume to get them this far and I think that they will still break in some more over the next few months.

 

[kringle77]

I forgot to mention that the dispersion of highs and mids was pretty darn even across a 90 to 120 degree field using just the betas. I didn't really hear too many upper frequency hot spots until turning up the 8" jensens. They of course, have alot more going on up top where you would notice and peaks or dips in the frequency response off axis. I am really chomping at the bit to play this cab at this weekends gigs. Both are in really shallow rooms where this kind of cab could really excel.

 

[kringle77]

Alright, we may as well get this out of the way. I gigged the new cab last night and I wasn't totally right. The construction, tuning and all the other things I mentioned were right on. Things are different inside than outside. The low end held up and it really does have great dispersion. But, crossfiring has a factor that I couldn't predict. When using betas in a forward facing cab, many of the mid freqencies are additive and produce an certain growl or rough sound that is almost annoying on it's own but works great in a mix. By crossfiring I gained alot of dispersion but lost some of the additive mid range. So, it looks like I'll be dropping back and punting for moment. Im going to load the betas into one of my other cabs and see if those mids come back. It they do, this thread may have a revision 2. Don's cab is really nice and much easier to move than my berg so, I'd like to persue this more. In the mean time I'll continue to use my NV610 with one of the 10's replaced with a Jensen C8R crossed over. The new cab is currently being broke in more with some low frequencies. Im actually not that dissapointed because the cab sounds great, I learned one more thing about cabs and it really didn't cost me as much as you would think.

 

[rpsands]

Two things:
1) I bet the midrange sound of the beta drivers is just flat out different than the berg drivers (which probably have an OEM tweak or two)

2) You may want to check the stuffing in the cabinet. If it's over or understuffed it may play into how the distortion characteristics work.
(My experience with Don has been that he tends to line, not stuff, and you just need more filling in a sealed box)

 

[kringle77]

This time around I made sure that he stuffed the cab. It's tight but thick, good stuffing material. Tonight Im loading up my old 8x10 with betas and comparing it directly to my berg. I have the TS parameters for the berg drivers and the only difference at all is the berg has an fs of 51hz and the beta is 53hz. Thats it. The betas do have a bit brighter sound. After today I'll know if it's the crossfire or the betas that is sinking this project. I actually will first try 4 b810s with 4 betas, then all betas. If the betas still dont' sound like the berg cab then, there is more going on with the drivers than the parameters suggest. If it does sound the same, then it's the crossfire changing the sound. If the betas actually arent' as close as they look, maybe I'll load up the crossfire cab with the b810's. It sucks that this cab didn't work the way I wanted to right out of the box but, I actually enjoy this experimenting. It will solve some sound mysteries too. I'll report back tomorow. My home computer is sick and I can only communicate with the outside world on my work computer. I may be experimenting with b810s crossed over to the beta 10 cbmra driver at 500hz as well. That looks promising too.

 

[JGR]

I thought Eminence would only give TS specs for OEM drivers no longer in production - are you sure they are the right ones? Is the Qes the same for each driver? Wondering about the EBP since we're talking sealed cabs. Do the cones of the Betas and Bergs look identical? - a lot of the mid and high end characteristics will come from the break up nodes which you won't know without the plot for the OEM drivers. I still think Jim did more than just ask for a 24 ohm Beta.

I think trying the b810s in place of the Betas is a step in the right direction and I hope you are able to get where you want to go with a little more tweaking. . I'm currently stuck in the middle of the desert instead of at home working on my cabs... . I think your 8s will sound better than the new closed back 10 - it has a pretty ugly response.

 

[kringle77]

Last night I ran the berg next to an ampeg 8x10 loaded with half betas, half b810's. That sounded pretty huge. Then I ran all 8 betas. Here is what I came up with. The berg drivers have the same specs only different ohms and an fs of 51hz instead of 53hz. The bergs have alittle more going on down low and the overall response is flatter than the betas. The betas are brighter but have alittle scoop around 700hz. The bergs are just alittle flatter and fatter. I have to admit it, the bergs are better drivers and just plain great, even if alittle dark.

Also, I loaded 4 B810's and and 2 betas in the crossfire. A definite improvement but still, the sound is smoother where, a front firing cab is more aggressive, though more directional as well. Like BFM has said, a single mid or vertical stack of mids has better sound than even the crossfire. Back to the modded berg.

By the way, Looking inside Don's cab, it is every bit as well built as the berg, he just does solid work everytime.

 

[will33]

Being a fairly shallow crossfire angle, I would think out in front of the cab there's a pretty wide area where the mids from the 2 columns are additive, but maybe there's some wierd lobing going on.

Some of those stronger, but "rougher" sounding mids from the flat front cab likely to do with comb filtering lower in frequency as well as having a "hotspot" on axis full of mids, at the expense of poor dispersion and a less "cleaner/clearer" sound.

As far as the Berg OEM's, they would be fairly close, but, changing one spec has to affect the others. Using a 24ohm coil would affect something more than just Re/impedance. The slight difference in Fs also indicates a slightly different cone, or at least cone mass and/or likely different dustcap material/composition/mass/thickness, etc. They can also change the way the magnetic field behaves in and around the gap. Those things may not be noticable in outward appearances and do make pretty small changes compared to stock, but, those changes occur where our ears are more sensitive and can sound like bigger changes than they are in the specs.

This assuming whoever tested them's equipment was calibrated/zero'ed, etc. and both the Berg and stock Beta were tested under identical conditions. Same day, time, temperature, humidity, driver break-in....all that. Add to that also the % tolerance in different production runs, etc.

Still lots of variables in there.

 

[kringle77]

Yup to all of that. The brightest sound is 0-12" from the grill. That seems to be the point where all the comb filtering happens and the tone smooths out after that, and becomes less bright. I wouldn't have predicted that. I should play guitar through it. That may be a positive for a bright guitar rig.

 

[JGR]

I wonder how much of an improvement you get from cross-firing verses the staggered driver arrangement in the Berg which, while not perfect, is still better than side by side. I still think the differences between the cabs, as well as the lack of top end in the stock 610, is from the drivers rather than alignment.

 

[rpsands]

Lower FS will change all kinds of stuff in the midrange - lighter cone = higher fs = more mids. Generally. IIRC, differing Q's of the system will change the midrange balance too.

You might try experimenting with the amount of stuffing. It could be overdamped by too much stuffing lowering the Q too much.

 

[kringle77]

I don't recommend the crossfire design. It takes too much of the focus and character away. As for the berg, I don't know what that offset does. It's only offset by about 1/3 of the driver height and they are pretty much spaced as wide as an ampeg cab. So, I just don't see the benefit other than getting the drivers 3" closer to your ears. If I like this 10fe200 I may decide to get 6 or 8 of them and load the ampeg cab with them so that I can compare them side by side with the berg to see if the dispersion is any different. I would think that you would be further ahead to just get the drivers as close together as possible rather than keep them wide and just stagger them alittle. If someone could explain that to me, I'd appreciate it.

 

[JGR]

If all else fails, you should try the NV412.

 

[kringle77]

JGR, I loaded the crossfire with the berg drivers and low and behold, it sounds exactly like when it was loaded with the betas. I stuck my head into one of the speaker openings and started talking. There is alot of ring in there and it is not dead like the berg or ampeg cabs. The stuffing don used is the same type used in most ported cabs and it's not doing much for the sealed cab. So, I stuck in 3 small scraps of matress topper that I had into the cab and most of the ring went away. So, Im going to walmart tonight after work to get some foam and re-line this cab. I do prefer the faital's tone to the beta's by the way so, if the faitals work out I may go for the full 8x10. Maybe this crossfire design isn't dead in the water afterall. I'll post back tomorow, my home computer is still dead.

 

[rpsands]

Yep, this is exactly what I was getting at by suggesting you mess with the stuffing Good find.