Headed in a good direction though only cross section as resistance makes the transformer part tough. Roughness of the inside of the pipe as resistors as well helps a bit
My moms boyfriend tried to explain to me back in the 80s this concept of why he always put the bass di backwards but I never got it till now. Thank you for explaining this.
Indeed, there are individuals who deserve an award for the way in which they present the technical fundamentals within the scope of sound technology, making it possible for the largest possible number of people to benefit from it. It is undeniable that this channel of yours is a credible source of information, for those who really need to understand the fundamentals. The signal level issue is an example of this. For this, I express my thanks to Dave Rat. I will continue here, no doubt.
I couldn't agree more. We just need to post a playlist created and have a link pinned in all sources (forums, discords, reddit, Instagram, Facebook groups..etc) Dr. Audio 'DR' please create (or rename mix) for a playlist mixing for newbies, experts for us to link? Cheers!
I used a DI box this weekend! I do video production for dance competitions. I take the line-level output of the soundboard backstage and ran it into a Radial DI box. Then I'm able to send the balanced mic-level signal over 150 feet to my camera in the back of the auditorium. It works great! Plus having a ground-lift can be useful if you experience any buzz or hum. DI boxes are wonderful! 😊
The best thing about using a DI backwards I’m my opinion is reamping. Most “re amp” boxes are just DIs with reversed gender XLRs. Somewhat embarrassed to admit here, but I purchased an active REAMP box from radial. After some time of using it in the studio, I A/B’d with my basic radial passive DIs in my live mic kit. There was little if any difference at all to the signal. So yeah, using the the DI backwards to reamp or extend gtr signals is awesome and adds another solution/option into the mix using something you already own. Cheers!
The thinking persons sound tech tutor. You can tell the man's brain is always working to make things better for bands and audiences and he has an uncanny skill of making it all understandable. Keep 'em coming Dave. S.
I used to always run two Multiformat, one for microphone level signals and the other for line level signals (both directions), sometimes even going up to three multicores, microphones, line inputs, line outputs, and would (mostly) use the mixing desk line input on the channel, exception being if I had mic input transformer on the desk then I would sometimes input a line signal through it for some transformer saturation, still do that till this day with my Allen & Heath Mod Two desk (the one from Pink Floyd-Live in Pompei), I believe it has Carnhill input mic transformers, beautiful original 70‘s saturation….by the way I love your videos Dave, your giving answers to a lot of what many people may think of as „stupid“ questions and then doing real life demonstrations , unfortunately many people think the only difference between signals is how „big“ or „loud“ they are, I cannot even begin to count how many times I’ve tried to explain to people the concept of impedance matching and the different topologies of pre-amp and amplifier topologies, took me a while all these years ago to understand why desk interactions happened when there was no transformer split, eg.a straight y-split going to one desk with transformer input and the other electronically balanced, or worse both electronically balanced but not identical desks, „shit, it works with two Midas desks, why not two Toys‘r‘Us desks???“ Yup, transformers are expensive…..and very often the effect of the transformer is a beautiful thing,a little fattening of the signal, a little rounding off, and a special kind of compression sometimes…it’s a pity that people often don’t realise how useful this can be in shaping the sound….and you haven’t touched on inductors for parallel eq or capacitors for filtering, trying to explain parallel eq is very confusing for many who still think in big-small signals or even more simplistic quiet-loud…..and now we are into the effect of phasing on a signal….for many non technically minded people you are doing VooDoo…🤣🤣🤣🔊🔊🔊🔊
First and foremost I always enjoy and learn from your videos, so thank you for that. I just wanted to say your analogy of impedance and current and voltage using the stick and fulcrum point was one of the best explanations I have seen since college. Bravo and keep them coming please Sir.
I really appreciate the difference between your tutorials and comments and those of audiophile sites who propose that everything needs to be absolutely perfect and that power cables make a difference that we can hear. Thanks
Ha, selling smakeoil is big business And as much as I find it distasteful there is a karmic balance to the equation of those that are willing and desire to follow blindly against logic being relieved of their finances by those that take advantage of them They both get what they desire.
Dave, Theses are awesome videos. How much do I wish RU-vid , and videos like these had been around in the 80’s . When I started playing/ working with audio gear. Would have helped to make a pile of Peavey, Crate, Audio Centron ..,, and some home built stuff sound better.. maybe., Thanks for sharing a lifetime of knowledge. As some say you might have forgotten more about audio than a lot of people will ever know.
Hi Dave, Mr.Wolf here , just wanted to tell you are doing an awesome work with your channel, I show lot of your myth busters to some of my students. Thanks for being so awesome with all these tests, thanks for taking the time to teach others and for your humility and kindness
Wish you were doing this when I was active in Audio Engineering!!! Gr8 vids Dave!!! Still learn something new even after I've retired due to health! Thnx much!
Thanks Dave, this is amazing information you're sharing! One note on that ZOOM H4n - it is a little funky but you can actually feed line level into the inputs but you have to run them in via 1/4" which is how the H4n knows you're giving it line level instead of mic level. Of course a DI is a great way to do this more universally.
Hmmm, the 1/4 seen to reduce the level that is recorded but the high input level seems to still distort the circuit before the the level reduction. I will set up a test to show the issues if I get a chance.
@@DaveRat Good point - I suppose it depends on the levels coming off the board. I tested it with an Allen & Heath SQ-5 but we were only running spoken word audio through the board. Could be different with music, especially anything on the louder end of the spectrum.
No, it's a GOOD analogy! It's like the one I use for batteries with water between 2 reservoirs and the diameter of the hose. Pressure velocity and flow are good analogue of watts, volts, amps. resistance with friction works too, and torque for impedance works too.
The coolest thing I've done with DI's was to act kind of like splitters and used them on the inputs of a friends BOSS RC-300 looper pedal so that I could tap the instruments before they went into the looper. That way I was able to break up the looper setup into 6 individual channels (3 for the loops and 3 for the instruments). That way the same guitar input could be used to input a rythym guitar part into the looper and then turn around and take a lead on it and I still had control of the mix of the individual parts and loops at the board. I know it was overkill for a looper setup, but it sounded way better because I had way more control over it, instead of it being all in one stereo output.
Great video. Your descriptions are very creative. Running a DI backwards is great in a pinch, but for long-term use, I still prefer devices designed for the job. Microphone transformers work well for low to high impedance conversion, and there are special interfaces for connecting consumer audio devices to balanced inputs. You might have also spent a bit of time on the pad switches on most DI boxes and when to not use them. But then we might have been here next week. 🥴👍🏻🎶🙉
Well done..... I actually bought radio shack low Z to hi Z transformers because I thought using a passive DI backwards would not work. I still have so much to learn.
Needless to say (but I will anyway) it's also a great way to re-amp guitars. Or re-amp anything, really. Blast your recorded drum track through an Roland JC-120 turned up good and loud in a nice sounding room, record the ambience and now you have a really interesting sounding reverb.
cool cool , as usual! What about Impulse response and phase of passive vs active DI ;) would link nicely with your comment about passive annalogue filtering with 2 DIs.
Thanks for this, could you please make a comparison video with cheap/entry level Active and non active DI's versus semi pro versus pro DI's? Would love your take on this subject :)
I ALWAYS learn from your videos. Thanks Dave! I currently send a single D.I. feed from my bass player's multi-effects pedal to our mixer for mains and monitors. I want a dry feed as well to give us a bass sound for the mix that is more consistent in tone and volume than I get from a completely wet feed now. I plan to route the bass through a Radial Stage Bug SB-2 for a dry feed to the mixer, send the 1/4" out from the D. I. into the effects pedal and back out to a 2nd D.I. and on to the mixer as a wet feed. I expect a hum and hope to remedy it with the ground lift switch. Should I expect any other issues? Do you recommend another solution? Thanks for your time and consideration.
With the Zoom recorder, the XLR inputs are mic level, and the trs inputs are line inputs. It’s an odd implementation of combo xlrtrs, but I just wish they had an optional pad..
You've made me start thinking like a mad scientist. Does impedance affect frequency response? If I underpower a PA, what frequencies are the first to go? If I play low quality music during a pre-show, will my sandwich also taste better? Thanks for the inspiration!
"Why would you want to use a DI backwards?" Something I heard from a recording engineer is a "double DI" method -- you want the guitar player either in the control room or super far away from the amp, you can get 2 DI boxes with a female/female XLR connecting them -- with some (probably miniscule) signal loss you can get that guitar player a couple of hundred feet from the amp running most of the signal across the balanced XLR. Anybody have practical experience doing this? I haven't tried it myself.
All good, that's a simple way to get a long run and for guitar, the losses in the di's should be less than no di's. Also going the other way and converting from low to high and back to low to create an analog passive low pass and get a warmer sound is another angle
The double DI box is a definitely a “thing”. Works great! We have a current recording session in place with our practice space set up with guitar cab/ head and board is in a camper/control room. Musician plays in “control room” with tracks to monitors (like a studio would do) and pulling directly from instrument and sending back through a 250’ Whirlwind 32/8 snake to amplifier input. Also picking off signal between head and cab with DI and sending back to board for capture. In the past, have also used a Whirlwind Director DI (in a pinch) as a ¼” speaker line extension junction box, when existing monitor location needed to be moved further than speaker line would reach. Grab another ¼” speaker cable and a DI and bam, longer cable. The In and Out are in parallel (Whirlwind Director), FYI.
I've heard that passive, transformer based DI boxes can ruin a single coil bass or guitar tone, because it can load the pickups down. In that case, if you need to plug a passive instrument to a board, the best scenario is to use an active DI, or even no DI at all, taking care to plug it on a high impedance input if possible? In my mind, passive, low signal devices need high impedance inputs, including dynamic mics... or am i wrong?
Is there a difference between a passive DI and a Reamp box? Or is a reamp box basically a passive DI with a potentiometer to fine tune the level? I use a re amp box to send a line level aux to my Roland Space Echo and then into a DI then into my console mic pre.
There’s a difference in the ratio of the transformers. A passive Di is around 10:1, a reamp is usually about 4:1. A passive Di in reverse, will take that line out (+4) and multiply it by 10, you’d need to pad it about 30dB or you’d over load your (instrument level?) Space Echo input. Your reamp transformer will take that line output and step it down 4:1, which is what you want. I don’t mean to confuse, and anything Dave says, I would not question.
Active systems usually send the signals at higher levels reducing the susceptibility to induced noise. Also active systems can minimize loading down the source by being very high impedance.
I always wondered whether the Freq Response changes when you invert the DI Box. Will have to try that one in my lab. Any comments your way ? Thanx from Caracas !
As long as you don't try and drive a lower impedance load, it should be the same either way. And awesome! Caracas! I was there once and it was fascinating.
@@DaveRat So true, plus tryin to keep the HighImp wiring as short as possible. Hey, when did you visit us out here ? I studied ElectroAcoustics in Boston in the 70s, toured extensively as Engineer and Stage Mgr and now (67 is an age you stop hopping on stages) am dedicated to my Electronics Lab, fixing vintage and pro gear out here. All the best to you !!
Calling Mr. Rat! I have a technical question for you. I am running a consumer grade HK preamp into a Driverack 480 (going unbalanced RCA to XLR by grounding the shield to ground). The issue I am encountering is that due to the impedance mismatch (I think), the preamp really struggles to get a high level signal to the 480, and consequently is real easy to run the pre into clipping. Would a DI box like the Radial ProD2 improve my signal to the 480 and keep the pre from clipping so easily? I don't have a full understanding of how these DI boxes work, but after watching your video, it gives me some hope that these might be just the ticket. I appreciate your videos and willingness to share your wealth of knowledge, -thank you!
Hmmm, sounds like you have a minus 10db output driving a plus db input and you need to find 14db somewhere. So, either raise the input gain like 10 to 14 db on the 480 or add piece of gear, like a compressor or something with 10 or more db of gain between the two. Using a di box backwards would be too drastic. A Rolls promatch is a box designed for that purpose as well
If the xlr input on your driverack is balanced (and I'm assuming it is), you want to use a DI box. If it is balanced, the way you have it set up now forces the driverack to accept a single ended signal. There' are different ways a component can be balanced, and the wiring can be different depending on the methods used. Given that, the results of using a cable like you describe can range from working OK to crossing wires and making a short circuit. Without knowing the details of how your equipment is made, its hard to say what is going on in your system. Either way, the issue you describe is a textbook example of why you should be using a DI box in the first place. I think if you try one, you'll be pleasantly surprised with the results.
Ciao! So if I understood well, the correct way to plug a stomp box reverb that I love to my console is to feed the reverb's input with an aux send (+4 balanced) with a backward DI box in the middle, and the plug the reverb's output through a DI box (this time withh a "regular" way of pluggin) then send the signal to a mic input of the desk. Is that correct? Thanks for all!
Hmmm. You don't need the 2nd DI and the output of the stomp box is not an issue for the console to deal with. To send to the stomp box, the console output is found to be pretty hot, so either turn the output way down or use a DI the normal way to drop the level down. That said, a DI typically has a mic level out so it may be a bit low for the stomp box input. I'd give a try and see which works better
@@DaveRat Hola Dave! I plugged the input of the stomp box the way you explained and cool! that's the only way to feed with a proper signal the input of the pedal himself with (also) hot signals coming from the +4 dBu converter balanced output. I test the flow with no flipped DI and there was no way of hearing "dry signal" coming back clean from the pedal; always "cruch". So I thank you very much for this top useful piece of advice: It makes me think that the next time I want to use my friend's fostex E16 for tracking drums, I will need at least a rack of 10 radials (which I used for patching this time_1XJDI with Jensen) passive to hit the tape... Also, as you suggest, I patched the rev pedal's output directly in a mic preamp (padded) and there is enough room to align. Thanks again for having my rev pedal connected properly to the rest of the world! Ciao!
He from London Dave. thank you so much for your video. I like to ask you about the DIbox what do you think we can use the output from the console to DI box to The speakers ?
@@DaveRat he Dave I think I put wrong the question:))I'm sorry My question is, can we use the DI box between the console outputs and main speakers? Thank you Dave.
A di box will drop the voltage to mic level. So, yes, if your speakers only take mic level. If you are trying to solve a buzz, use an line level iso transformer instead
@@DaveRat I think it makes more sense after watch #2. The information @3:30, where you speak of getting everything into the same level range. This makes sense and is somthing I had not thought of. I've always thought, balanced and shielded means I'm good to go and should have no worries about crosstalk. This information indicates the possibility is still there and therefor it's beneficial to get the levels in the same range. A practical example of this is where I may be sending a signal for an active floor monitor to a station on stage along the same snake I'm using for microphones. I've not experienced any noticeable crosstalk. Thinking about the components, I just verified the outputs of my stage box are +4db and the mics are a mic of dynamic and condenser. Have I been getting lucky? @11:35, with what happens as the signal that has been converted to high z is fed into the low z input of a console, it sounds like you may loose some of the signal content once processed by the console. Maybe a roll-off of the upper and lower frequencies is occurring . Am I still out in left field?
You are on track. And though the crosstalk is minimal or non audible, the bigger issue is if there is a fault. Snake gets punched and shorts a speaker send to a mic input or a mis patch sending high level to a mic. That said, if it works all good, but as the importance of a flaw free show increases, so does the caution and best practices. Separating return snakes is one aspect. Avoiding super hot inputs mixed with super low level inputs is another way to steer a bit clearer of potential mishaps
@@DaveRat Great recommendation. A good idea to keep the connections safe in the case of the eventually inevitable mishap in the live gigging environment. You mention using a separate return snake for higher line level signals. If I am assessing the scenario and best results desired correctly, the only way to use a separate line within the same snake as a return safely I would need to step down the signal from line to mic level between the stage box and the feed of the snake that then goes to stage. Does that sound correct? If yes, then I am thinking one of our little transformer equipped direct boxes in a 10 to 1 ratio would be the fix as you have shown here in these videos. I would think something a little different with balanced in and out would be ideal. Thank you for taking the time to respond to my questions. It is much appreciated knowing who you are and likely how busy you must be, I am honored.
If you're not having an issue and you want to run a single snake I would just go ahead and run the returns down the snake don't step up or step down and add the complexity which can create its own issues
Hmmm, though transformers can be designed to induce phase shift, audio transformers offer little to no shift in the passband. I think you are thinking of inductors.
Dave, what do you think about reamping with a backwards di? I’ve done it and been happy with the results but I’ve heard a lot of naysayers. What say ye?
Sort of. On the unit I have, H4n, the 1/4" are about 14 db lower than the XLR. But, with high level inputs something before the input level control clips around the same level on both. So it is almost like all the 1/4" does is offer the ability to turn it down farther after it has already distorted.
How can low impedance have a lot of resistance? Some of the stuff he says just doesn't make sense. The explanation he gives at around 11:20 mark just makes no sense. I understand what he was saying about the DI working backwards, it is the analogy he is using, it just confuses me.
Yes, could see how "a lot of resistance" can be confusing if interpreted as "a high resistance". I switch between the analogy where offering "a lot of resistance" to the wooden stick moving would equate to and be the result of the low input impedance. The low input impedance (low resistance) of a balanced input will drag down the output voltage of a high impedance output.
