Hi Chaps! I have built a a set of OB's using a B200 and 2 X Alpha 15's per side, but I cannot no matter what I try get any decent amount of bass from the system! Don't get me wrong, I am not expecting subterranean earth shaking bass, just something musical, and visceral.
I am currently using the system active via a Rane AC22B X-over, and the bass drivers are wired in series (I did try them for a while in parallel, but the load seemed too great and there was hardly any bass...) and powered using a Sure 4 X 100W board ( I have tried others including a hefty hypex unit)
So, what am I asking/. well, I am hoping someone can come up with an alternative design, presumably with the B200 in OB, maybe the Alphas in another arrangement? I am not limited by WAF, just by cost, so cheap and cheerful!.
The option I have seriously considered is using the B200 alone, in an OB and going back to passive with maybe a small tripath (trends for eg.) or valve amp. If this can be done while providing at least a modicum of musical bass I will be happy.
I know that is a lot to ask, but any ideas / experiences would be very gratefully appreciated. Many, many thanks in advance, Steve.
I am currently using the system active via a Rane AC22B X-over, and the bass drivers are wired in series (I did try them for a while in parallel, but the load seemed too great and there was hardly any bass...) and powered using a Sure 4 X 100W board ( I have tried others including a hefty hypex unit)
So, what am I asking/. well, I am hoping someone can come up with an alternative design, presumably with the B200 in OB, maybe the Alphas in another arrangement? I am not limited by WAF, just by cost, so cheap and cheerful!.
The option I have seriously considered is using the B200 alone, in an OB and going back to passive with maybe a small tripath (trends for eg.) or valve amp. If this can be done while providing at least a modicum of musical bass I will be happy.
I know that is a lot to ask, but any ideas / experiences would be very gratefully appreciated. Many, many thanks in advance, Steve.
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Hi Aquapiranha,
If you're not getting monster bass, I would suspect a phase / wiring issue. After that, a room issue. After that, maybe the baffle is just too narrow for the bass you're expecting?
I have the same Rane xover and the B200. I'm wondering:
(a) how low do you get (have you tried test tones maybe?)
(b) what xover point are you using on the Rane?
(c) how are you going into the Rane's XLR? Does your pre have XLR out or, if RCA, are you using level/impedance matching box?
(d) Have you read this MJK article? The setup is similar (4 Alpha's, active crossover): Project 7 : Lowther Open Baffle System Design Project
If you're not getting monster bass, I would suspect a phase / wiring issue. After that, a room issue. After that, maybe the baffle is just too narrow for the bass you're expecting?
I have the same Rane xover and the B200. I'm wondering:
(a) how low do you get (have you tried test tones maybe?)
(b) what xover point are you using on the Rane?
(c) how are you going into the Rane's XLR? Does your pre have XLR out or, if RCA, are you using level/impedance matching box?
(d) Have you read this MJK article? The setup is similar (4 Alpha's, active crossover): Project 7 : Lowther Open Baffle System Design Project
Hi RJ, many thanks for the response. Out of interest, can you describe your set up in more detail?
I have not tried test tones, but suffice to say I was getting a lot lower in the same room with a Sachiko and FE206E.
I am using adapters with the Rane, and I appreciate that this means a loss of 6 db, but that is treble as well as bass.
MJK very kindly assisted me with the design, and advised me on the sizeof the baffle, I will try to find the mail.
I have read the article, but I am not very au fait with the theory to be honest.
does anyone recommend using a different set up for the bass? maybe a H frame or similar, maybe a box?
Thanks, Steve
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You should have earth shaking bass with those woofers... well, you certainly should have bass. Check your crossovers and whether you have them configured them incorrectly.
I had a similar thing going on for a while, with a single 15A per side and it turns out I had some errors in the crossovers. Even with one per side, there is enough bass to wake the neighbors.
I had a similar thing going on for a while, with a single 15A per side and it turns out I had some errors in the crossovers. Even with one per side, there is enough bass to wake the neighbors.
Yes you are correct. I do not even want massive bass, just something tangible and real. I have been thinking and now I think I will look at the x-over. It is set up correctly, but I have a suspicion it might not be doing its job properly?
I need to finish my LDR so that I can run the signal directly into the bass bypassing the rane, who knows? maybe the rane is u/s?
any other ideas would be great, or anyone selling a dbx driverack pro for peanuts....?
Try these crossover points:
Alphas: 120 Hz 12/db oct. L-R
B200: 300 Hz 12 db/oct. L-R
Alphas better be wired in parallel. Make sure yuu try it with another, capable SS amp, as it can make big difference.
Also, For Visaton you may want to try a 0.68-1 Mh inductor with 6.8-10 Ohm/ 10-20 w resistor (try different values to suit your taste) in series with a positive lead, between a speaker and the amp.
It can be a bit painful and time consuming until you hit the right combination, but it's worth it.
Alphas: 120 Hz 12/db oct. L-R
B200: 300 Hz 12 db/oct. L-R
Alphas better be wired in parallel. Make sure yuu try it with another, capable SS amp, as it can make big difference.
Also, For Visaton you may want to try a 0.68-1 Mh inductor with 6.8-10 Ohm/ 10-20 w resistor (try different values to suit your taste) in series with a positive lead, between a speaker and the amp.
It can be a bit painful and time consuming until you hit the right combination, but it's worth it.
On the multiway Systems Pictures and Descriptions thread, you can see my system on Post 1763. It is very similar to yours, and even moving the crossover up to 5khz instead of 1.2khz, reducing the treble hump, made great improvements to perceived bass.
The rising response top end of the B200 is far more sensitive than the bass from the alphas. I do not know if you have done anything about this but the system is commonly held to be unlistenable until this is dealt with, and the volume will be unbearable before the bass gets going.
As a test, if you turn up the volume with the B200 disconnected, can you get satisfactory bass that way? If so, then it is just a matter of balancing out the sensitivities of the B200s and the alphas.
Ditto to getting those alphas in parallel (4ohms) versus series (16ohms).
The rising response top end of the B200 is far more sensitive than the bass from the alphas. I do not know if you have done anything about this but the system is commonly held to be unlistenable until this is dealt with, and the volume will be unbearable before the bass gets going.
As a test, if you turn up the volume with the B200 disconnected, can you get satisfactory bass that way? If so, then it is just a matter of balancing out the sensitivities of the B200s and the alphas.
Ditto to getting those alphas in parallel (4ohms) versus series (16ohms).
Thanks guys. I have tried adjusting the crossover point on the rane, as well as the gain of the treble against the bass, and this made no difference other than to dull the sound. With the gain for the b200 on 2/3, and the alphas on full, there is still hardly any bass output. I have tried changing from parallel to series and this made little difference either. I did not want to go down the route of messing about with a passive crossover, hence me using the rane.
Hmm.... I need to have a good think. I have seen people with a similar set up saying that the impact and bass they get is incredible, so there must something seriously awry here I think.
Steve
Hmm.... I need to have a good think. I have seen people with a similar set up saying that the impact and bass they get is incredible, so there must something seriously awry here I think.
Steve
Hi aquapiranha,
1. This still sounds like a phase issue to me. Are you willing to do the battery test to rule it out? You just connect a 1.5v battery to each woofer and make sure they all move out when the battery's polarity is the same on each. If one woofer moves out while the other moves in, or Left and Right are out of phase, you'd have exactly the phenomenon that you've described, in my limited experience.
2. Level matching: If you are using straight-through passive adapters for RCA-to-XLR and XLR-to-RCA, you have a level/impedance mismatch with the Rane's pro inputs. Specifically, the RCA -10dBu is not really enough to properly drive the +4bDv XLR inputs. To get a proper match, I am using a $50 box that has a potentiometer on it, which steps up the signal and matches the impedance. (I use a total of two of those $50 boxes.) It still sounds like more of a phase issue.
(P.S. in answer to your question, my setup is B200, Rane, and bass bins -- at the moment, the bins are K-Horn copies but we are restoring some really beat-up Klipsch LaScala bins.)
1. This still sounds like a phase issue to me. Are you willing to do the battery test to rule it out? You just connect a 1.5v battery to each woofer and make sure they all move out when the battery's polarity is the same on each. If one woofer moves out while the other moves in, or Left and Right are out of phase, you'd have exactly the phenomenon that you've described, in my limited experience.
2. Level matching: If you are using straight-through passive adapters for RCA-to-XLR and XLR-to-RCA, you have a level/impedance mismatch with the Rane's pro inputs. Specifically, the RCA -10dBu is not really enough to properly drive the +4bDv XLR inputs. To get a proper match, I am using a $50 box that has a potentiometer on it, which steps up the signal and matches the impedance. (I use a total of two of those $50 boxes.) It still sounds like more of a phase issue.
(P.S. in answer to your question, my setup is B200, Rane, and bass bins -- at the moment, the bins are K-Horn copies but we are restoring some really beat-up Klipsch LaScala bins.)
I have just tried the battery test, all drivers move forward when the +ve ic connected to the +ve on the battery and the -ve likewise.
So, I have just connected an old arcam alpha amp to the bass speakers only and the bass seems to me to be very woolly and indistinct still... ( drivers are still in series, ie 16 ohms, but when they were in parallel they still lacked output) this is getting worse!
Steve
So, I have just connected an old arcam alpha amp to the bass speakers only and the bass seems to me to be very woolly and indistinct still... ( drivers are still in series, ie 16 ohms, but when they were in parallel they still lacked output) this is getting worse!
Steve
Hi aquapiranha, how about this:
1. Skip the B200's and the Rane, and just drive the Alpha's full-range out of one of your power amps? Pre -> Power amp -> Alpha's. If you suddenly hear lots of bass, the Rane or the RCA/XLR wiring is bad.
2. Battery test: can you do the battery test at the speaker wire's that go into the power amp? In other words, so that the battery powers both drivers at once? And then repeat for the other channel? This would reveal if there's reversed polarity sneaking in somewhere.
Hang in there, dude! You're almost out of the woods.
1. Skip the B200's and the Rane, and just drive the Alpha's full-range out of one of your power amps? Pre -> Power amp -> Alpha's. If you suddenly hear lots of bass, the Rane or the RCA/XLR wiring is bad.
2. Battery test: can you do the battery test at the speaker wire's that go into the power amp? In other words, so that the battery powers both drivers at once? And then repeat for the other channel? This would reveal if there's reversed polarity sneaking in somewhere.
Hang in there, dude! You're almost out of the woods.
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Hi. That is what I did in the post above. I connected one of my amps directly to the drivers without the B200 and it still doesnt sound right. I am going to reconnect the alphas in parallel and try that with the arcam amp next.
Many thanks for the help! Steve
Hi SAC. Your speakers do indeed look VERY similar to mine, and in construcion too. Tell me more about the crossover - did you design it yourself? (these things are wayyy beyond my simple mind) and if so, did you work off any plans that I might look at? I think maybe that might be a cure for my ills.
Thanks, Steve
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