Yep, you have to perform the surgery.
Or finagle with a boat load of EQ.
Personally a simple capacitor swap is not really that hard. Yes you void the warranty. But you have not destroyed anything either. You improved the low end for what you require.
Few prosound setups are interested in reproducing 16 hertz. That's why they cut it down from 30 hertz on down.
Little hint. Instead of tearing it open loosen the screws first!
Could not resist.
Or finagle with a boat load of EQ.
Personally a simple capacitor swap is not really that hard. Yes you void the warranty. But you have not destroyed anything either. You improved the low end for what you require.
Few prosound setups are interested in reproducing 16 hertz. That's why they cut it down from 30 hertz on down.
Little hint. Instead of tearing it open loosen the screws first!
Could not resist.
Nice charts. Thanks.
At 16 Hz, THD is therefore around like 25dB down which is roughly 8% or so (and the kind of lousy performance all of us who must use cone speakers in subs are used to). Seems good because nobody else that I can recall has anything to show us at all in that region (time to post you sub-sonic FR curves anybody?).
For sure, the distortion products are overwhelming the fundamental because you can hear the distortion way, way better than 25dB's compared to 16 Hz.
Yes, if somebody could produce a clean 16 Hz note loud enough, you can hear it, I suppose. Although that stuff about "regression" fitting suggests the hearing is, um, speculative.
But if say, Bach On had a flat frequency curve and he had his system turned loud enough so that people could hear the 16 Hz note when produced, the church would empty out immediately because the rest of the spectrum would be damaging to human ears.
Instead, the likely best approach is to EQ the lower end real loud so people hear the pedals (albeit along with the usual harmonics natural to a pipe organ).
Anybody ever see an FR for a pipe organ??? I bet the big pipes are far louder than the smaller ones.... at least to a mic.
Ben
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Not quite.
Basically when something is 24db or more down, except in the ears most sensitive range you are pretty much buried in the noise. It will not be very noticable.
I have demonstrated 16 hertz with a very low distortion horn loaded subwoofer. It had distortion products below 10%. Very clean sounding. And everyone heard the tones loud and clear. Was awesome fun using a 30 watt amplifier to do it to! Horns don't need no stinking kilowatts!
Basically when something is 24db or more down, except in the ears most sensitive range you are pretty much buried in the noise. It will not be very noticable.
I have demonstrated 16 hertz with a very low distortion horn loaded subwoofer. It had distortion products below 10%. Very clean sounding. And everyone heard the tones loud and clear. Was awesome fun using a 30 watt amplifier to do it to! Horns don't need no stinking kilowatts!
This is what happens why you buy before doing the research.
Back in post 772, before you bought the Rolls, I said "There's about a thousand threads about this issue on various forums, I could link a few dozen but just do a search. There's also mods to fix this issue, but modding brand new gear is not ideal. There are also some DI boxes that do flat frequency response right out of the box, but they are more expensive. There's also differences between models, new Cleanbox is different than old Cleanbox, which is different from Rolls, etc. There's a ton of info out there, it's best to look into this issue before buying."
I already did a quick search and couldn't find the Rolls response. But I did find a few DI boxes with flat response down to single digits in stock form. I also saw a couple of references that said the new Art Cleanbox might not need the mod but I didn't really look into it.
If you search hard enough you might find the Rolls response somewhere, or you can just measure it's response. I wouldn't go modding it without at least knowing what it's factory response looks like.
Also, if you have eq somewhere in the signal chain you might be able to just eq the rolling response back to flat. It isn't ideal but it's easier and better than modding brand new equipment which voids the warranty and could be trouble if you don't know what you are doing.
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C'mon, the high frequencies have a 60-80 dB advantage at moderate listening levels. So at 24dB they overwhelm the fundatmental. On music, the distortion goes unnoticed.... lucky, eh. Even during pure tone testing, hard to focus your hearing to separate the notes.
Horns are lower distortion due to impedance match to air as well as the usual sealed back-chamber. Way to go, if you are a consummate building like Mark.
Yes, 10% distortion in a cone speaker low end passes for "very clean" even for the picky audiophiles - even ESL fans. Too bad, though. Of course ESL fans expect much lower distortion than cones can provide higher up.
Ben
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Thanks, guys. I'll try to do a bit more research.
I'm not going to get deep into the debate about how many Hertz can dance on the head of a pin. I do know I could FEEL the sounds below 20 with this new box. I did feel it in my chest. What I "heard" may have been distorted overtones and/or partials. It is possible that some listeners may "hear" the fundamental in a full organ based on the other notes of the chord. Others may actually be able to hear AND feel the fundamental. I wonder if a key component in this difference might be the brain, rather than just the ears?
BO
I'm not going to get deep into the debate about how many Hertz can dance on the head of a pin. I do know I could FEEL the sounds below 20 with this new box. I did feel it in my chest. What I "heard" may have been distorted overtones and/or partials. It is possible that some listeners may "hear" the fundamental in a full organ based on the other notes of the chord. Others may actually be able to hear AND feel the fundamental. I wonder if a key component in this difference might be the brain, rather than just the ears?
BO
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Quick and dirty: just connect a bargain voltmeter (AC scale) from Harbor Freight to the speaker terminals. Then pump in single frequencies from REW's signal generator (or organ keys). That will put to rest what signal is going into the speakers.
If your signal is falling off at, say, 20 Hz, just see how much you need to crank up REW to get it back to level with 100 Hz.
Ben
I'll try that Ben.
I went to the Parts Express site and read the comments on the Rolls MB15b Promatch.
These comments can't be viewed as definitive, but I do notice that a few people were using this box as part of a subwoofer system.
That MAY be an indicator that the box can do the low sounds. Or not.
Rolls MB15b ProMatch Balanced/Unbalanced Converter 3.5mm/RCA/XLR
BO
Har-de-har-har!!!
When is the tryout for your HBO comedy special scheduled? 😀
BO
Those reviews are useless. Unless someone specifically showed a response graph or at least mentioned the response was flat to X db it's likely that the people who wrote those reviews know less about the unit than you do.
The simple answer is that it doesn't matter, not even a little bit. Whether you hear it or feel it or a combination of both, you can DEFINITELY tell when it's missing. The suggestion that it's not important because your brain fills it in is complete hogwash nonsense.
Try listening to REAL thunder, close thunder. Or a train going by at a few feet distance. Record it and immediately play it back on a regular stereo. Is it the same? Of course not. Not even close. If you didn't have the original to compare to you might mistakenly have the illusion that the playback of the recording on the cheap stereo was complete, but back to back with the real thing, there's no comparison. Your brain can't fill in the feeling of the ground shaking beneath your feet. Do you hear that or just feel it? Really doesn't matter, if it's missing, it's missing.
Hi Bach On,
Still on the road.
Looks like you have been busy.
The Rolls MB15b looks like a nice general purpose direct interface box for a good price. The Rolls website has a spec sheet (manual) w/ schematic:
http://www.rolls.com/pdf/M_MB15b.pdf
Going from unbalanced to balanced, the low end frequency response could be improved by increasing the 1uF input capacitors (C5/C6) to e.g.: 10uF, but even that may not be necessary, as the low frequency response is dependent on the position of the gain pot, and as long as the gain pot is not cranked to the max the response will be fine as is. You could always try to roll your own, but that sounds like a different project to me. The other thing you'll have to whatch for is the phasing of the XLR connectors, just make sure you used the same convention throughout your system. Rane used to have very good tech papers on grounding/shielding/interface - Google.
Have you tried to measure the impedance of the box yet? This should show you if the leaks you may still have are really bad or just bad.
Well, Y'all have fun. I gotta keep on working on this vacation thing, sofar we've made it from Odessa Texas to Lancaster, Ohio.
Regards,
Still on the road.
Looks like you have been busy.
The Rolls MB15b looks like a nice general purpose direct interface box for a good price. The Rolls website has a spec sheet (manual) w/ schematic:
http://www.rolls.com/pdf/M_MB15b.pdf
Going from unbalanced to balanced, the low end frequency response could be improved by increasing the 1uF input capacitors (C5/C6) to e.g.: 10uF, but even that may not be necessary, as the low frequency response is dependent on the position of the gain pot, and as long as the gain pot is not cranked to the max the response will be fine as is. You could always try to roll your own, but that sounds like a different project to me. The other thing you'll have to whatch for is the phasing of the XLR connectors, just make sure you used the same convention throughout your system. Rane used to have very good tech papers on grounding/shielding/interface - Google.
Have you tried to measure the impedance of the box yet? This should show you if the leaks you may still have are really bad or just bad.
Well, Y'all have fun. I gotta keep on working on this vacation thing, sofar we've made it from Odessa Texas to Lancaster, Ohio.
Regards,
Clarification etc
@ Bach On
I composed the following, before i logged in & saw tb46's helpful post. I'll post it anyway as you might find it useful as well.
Rolls MB15b Rolls Corporation - Real Sound - Products MB15b Promatch and More Has a DEAD link to the PDF manual ! But i found one here http://c3.zzounds.com/media/M_MB15b-bd9dd0944e0ee43b2e094d1fefae8636.pdf Strange that they have it & Rolls don't ? Anyway it includes the circuit diagram 🙂
You need to change the following capacitors to enable 16Hz to pass through without attenuation.
Using XLR input/s - C2 & C4 & C13 & C154 from 1uf to 10uf
Using RCA or 3.55 Skt inputs - C5 & C6 & C17 & C20 from 1uf to 10uf
All can be 16 Volt electrolytic. Observe the polarity on them.
*
According to ART's PDF, there is No USB on the Phantom 2 !
To me, it appears that you should be/are connecting the balanced Mic to the PHANTOMIIPro & then to one of the XLR inputs J1/2 on the Rolls MB15b. The output is then fed to the laptop via the USB skt.
Also connecting for eg, a cd player output/s to either the RCA J6A & J6B or 3.55 J7 Skt input/s, or use the laptop output/s via the USB skt on the Rolls MB15b, & then the output/s goes from either/both the RCA J8A & J8B or XLR J2/3 Skt/s to the amp. Adjust the gain via the Rolls MB15b knobs.
Is this correct ?
*
@ tb46
Keep on having fun, happy vacation 🙂
@ Bach On
😉
I composed the following, before i logged in & saw tb46's helpful post. I'll post it anyway as you might find it useful as well.
Rolls MB15b Rolls Corporation - Real Sound - Products MB15b Promatch and More Has a DEAD link to the PDF manual ! But i found one here http://c3.zzounds.com/media/M_MB15b-bd9dd0944e0ee43b2e094d1fefae8636.pdf Strange that they have it & Rolls don't ? Anyway it includes the circuit diagram 🙂
You need to change the following capacitors to enable 16Hz to pass through without attenuation.
Using XLR input/s - C2 & C4 & C13 & C154 from 1uf to 10uf
Using RCA or 3.55 Skt inputs - C5 & C6 & C17 & C20 from 1uf to 10uf
All can be 16 Volt electrolytic. Observe the polarity on them.
*
According to ART's PDF, there is No USB on the Phantom 2 !
To me, it appears that you should be/are connecting the balanced Mic to the PHANTOMIIPro & then to one of the XLR inputs J1/2 on the Rolls MB15b. The output is then fed to the laptop via the USB skt.
Also connecting for eg, a cd player output/s to either the RCA J6A & J6B or 3.55 J7 Skt input/s, or use the laptop output/s via the USB skt on the Rolls MB15b, & then the output/s goes from either/both the RCA J8A & J8B or XLR J2/3 Skt/s to the amp. Adjust the gain via the Rolls MB15b knobs.
Is this correct ?
*
@ tb46
Keep on having fun, happy vacation 🙂
Not sure why I didn't find this in my original search, but I did find it this time.
Looking for Xti-2000 starting point - AVS Forum | Home Theater Discussions And Reviews
This post suggests it has similar/same response as the old Cleanbox, has a measurement, and suggests the Rolls may be a clone of the Cleanbox.
Looking for Xti-2000 starting point - AVS Forum | Home Theater Discussions And Reviews
This post suggests it has similar/same response as the old Cleanbox, has a measurement, and suggests the Rolls may be a clone of the Cleanbox.
Just use the XLR to RCA cables (or thumb-sized adaptors... available at any music store) and away you go. Or the Rolls right out of the box. Too much scare talk here. Anything that mentions "18 Hz roll off" will be inconsequential to your sound. And might provide some heretofore overlooked driver protection (um, that's what sealed boxes are for...).
Consider measuring the size of your port in case you later will want to cut a piece of wood to seal the port and convert to a sealed box. Just sayin'.
Ben
Ben
Consider measuring the size of your port in case you later will want to cut a piece of wood to seal the port and convert to a sealed box. Just sayin'.
Ben
Ben
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@ Bach On
Crown XLS 1500 specifications
That "seems" like a mistake, as it says < 0.5% here http://rdn.harmanpro.com/product_do...XLS_Install_DataSheet_Web_050615_original.pdf
Funny how many manufactures have errors in their specs 🙁
Frequency Response is NOT the same as Power bandwidth
I don't see a Power bandwidth graph etc for the Crown XLS 1500 anywhere ? I would email Crown & ask them for the info.
Why the source/preamp/mixer etc & amp "Total combined" f3's matter, is because thay ALL have a cumulitive effect on the frequency response. They are ALL in series, which makes the f3 point cut off sharper = less bass. For eg only,
Unit A = -3dB @ 10Hz connected to Unit B = -3dB @ 10Hz = Total f3 = -6dB @ 10Hz ! If ANY units are worse than that, then the f3 will be even worse. Which means these things affect the 16Hz !
That's why you NEED to change the capacitors in whatever low level equipment you use, otherwise they will restrict your ability to produce 16Hz. If you do this, then if required the amp f3 can then be compensated by some sensible EQ.
If you don't do this, it doesn't mean you won't hear/feel anything, but you won't be getting the FULL result you hoped etc for, & with all the time/effort you've put into trying to achieve it !
Crown XLS 1500 specifications
That "seems" like a mistake, as it says < 0.5% here http://rdn.harmanpro.com/product_do...XLS_Install_DataSheet_Web_050615_original.pdf
Funny how many manufactures have errors in their specs 🙁
Frequency Response is NOT the same as Power bandwidth
I don't see a Power bandwidth graph etc for the Crown XLS 1500 anywhere ? I would email Crown & ask them for the info.
Why the source/preamp/mixer etc & amp "Total combined" f3's matter, is because thay ALL have a cumulitive effect on the frequency response. They are ALL in series, which makes the f3 point cut off sharper = less bass. For eg only,
Unit A = -3dB @ 10Hz connected to Unit B = -3dB @ 10Hz = Total f3 = -6dB @ 10Hz ! If ANY units are worse than that, then the f3 will be even worse. Which means these things affect the 16Hz !
That's why you NEED to change the capacitors in whatever low level equipment you use, otherwise they will restrict your ability to produce 16Hz. If you do this, then if required the amp f3 can then be compensated by some sensible EQ.
If you don't do this, it doesn't mean you won't hear/feel anything, but you won't be getting the FULL result you hoped etc for, & with all the time/effort you've put into trying to achieve it !
Yeah right. I've showed a couple of graphs now that show a loss of about 6 or 7 db at 16 hz. That's inconsequential? I suppose it might be to you, as every piece of advice you give is contrary to OP's goal (indicated in the thread title if you haven't noticed) of strong 16 hz.
Just sayin'. Sealing the box is going to lose ANOTHER 6 db or more at 16 hz. Add that to the lost 6 db from the "inconsequential" rolloff of the DI box, and IN THIS POST ALONE your advice is a loss of 12 db at 16 hz.
This is a pro sound application Ben, nobody uses sealed boxes for prosound sub bass. There's a long list of very good reasons for that.
I'd say that it certainly is consequential, if you're looking to produce 16 Hz and any appreciable volume.
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