Impedence Question - Balanced to Unbalanced

sk1939

Alright, I have a question. I'm working with professional audio, and I know all about mic impedances, Hi Z and Low Z inputs, and DI boxes and such, not to mention the importance of a balanced connection.

My question is, how do I best go connecting something with unbalanced outputs (DVD Player, CD Player, laptop computer) to the JBL's listed below (I know it has RCA inputs, but I have noise issues and need balanced connections). I have a balanced CD player but I don't usually use it (Teac Pro).

I have a 2 XLR to Stereo 3.5mm cable, but it just seems to wrong to me, not only for the difference in voltage (5V for XLR and 1.5V for 3.5mm) but also the difference impedances. How should I connect it/what should I use?

disneyjoe7

If I'm following you correctly the 2 XLR to Stereo 3.5mm cable, the cable could careless what the voltage is. The connector port cares what the voltage and impedance is, not the cable itself.

sk1939

disneyjoe7 wrote: »

If I'm following you correctly the 2 XLR to Stereo 3.5mm cable, the cable could careless what the voltage is. The connector port cares what the voltage and impedance is, not the cable itself.

The cable could care less yes, but I'm concerned my speakers will. Like I said the speaker has XLR inputs, the computer has 3.5mm out. The cable is 3.5mm to 2 XLR but the computer's output is like I said about 1-2V while the normal XLR has a higher voltage, and a higher level out (+4dBu) while RCA is (-10dBv).

CoolJazz

The JBL owner's manual doesn't specify the input impedance of the XLR. However, they do clearly say you can attach -10 inputs to all the connectors, so that would suggest 2 things. 1 - that you have enough gain typically from a -10 input and 2 - the important one, that it's probably a high impedance input.

You don't say much about your noise problem, so it's hard to tell what your trying to correct. But likely you've got noise on the computer output and are simply hearing that. If so, no connector or interfacing is going to correct.

However, the speaker is using a three prong grounded AC input. If they've got that ground tied to the audio ground (pin #1), then you will have a ground loop between the computer and the speaker. So plugging them into different AC sources may give you ground loop issues. Try first plugging the computer and the speakers into the same outlet.

If that's not possible, then you may be able to help yourself by looking at what the 3.5mm to XLR cable is doing. If it's ground is made from the sleeve of the 3.5mm and has continuity to pin 1, then lifting that will keep from having a ground loop. Short as possible wiring is important as well as crossing noise sources at right angles!

If you still have problems, then try to experiment with a small terminating resistance at the XLR. A high impedance input will have a greater likelyhood of "receiving" noise. Terminating it will lower this likelyhood. Try putting about a 10K resistor across pins 2 to 3 and see if that helps.

If this fails, then get a better sound card.

Good luck with it!

CoolJazz

sk1939

CoolJazz wrote: »

The JBL owner's manual doesn't specify the input impedance of the XLR. However, they do clearly say you can attach -10 inputs to all the connectors, so that would suggest 2 things. 1 - that you have enough gain typically from a -10 input and 2 - the important one, that it's probably a high impedance input.

You don't say much about your noise problem, so it's hard to tell what your trying to correct. But likely you've got noise on the computer output and are simply hearing that. If so, no connector or interfacing is going to correct.

However, the speaker is using a three prong grounded AC input. If they've got that ground tied to the audio ground (pin #1), then you will have a ground loop between the computer and the speaker. So plugging them into different AC sources may give you ground loop issues. Try first plugging the computer and the speakers into the same outlet.

If that's not possible, then you may be able to help yourself by looking at what the 3.5mm to XLR cable is doing. If it's ground is made from the sleeve of the 3.5mm and has continuity to pin 1, then lifting that will keep from having a ground loop. Short as possible wiring is important as well as crossing noise sources at right angles!

If you still have problems, then try to experiment with a small terminating resistance at the XLR. A high impedance input will have a greater likelyhood of "receiving" noise. Terminating it will lower this likelyhood. Try putting about a 10K resistor across pins 2 to 3 and see if that helps.

If this fails, then get a better sound card.

Good luck with it!

CoolJazz

Ah, well I'm pretty sure that it's not a ground loop (isolated grounds), but the noise is from what I can hear, an over modulated radio station that comes through occasionally, and for better or worse, the annoying cell phone buzz. I know the speakers are shielded properly, and it's not a sound card issue ( Echo Indigo DJ), because I've never had the problem in the past. The monitors are new, as is the location, and I'm not used to using devices with balanced inputs (previously I was just using just headphones).

dorokusai

The cell phone issue is easy, just keep it away from the system. If you can determine the actual radio station, you can isolate the frequency bandwidth.

You have 3 stated changes in your system, speakers, location and use of balanced cables....why does that mean everything else works fine?

sk1939

dorokusai wrote: »

The cell phone issue is easy, just keep it away from the system. If you can determine the actual radio station, you can isolate the frequency bandwidth.

You have 3 stated changes in your system, speakers, location and use of balanced cables....why does that mean everything else works fine?

It's always worked fine in the past. I noticed that using shielded cables gets rid of the cell phone noise, but I though that balanced cables should do the same. The problem is that the 3.5mm to 2 XLR isn't balanced, and gives noise. I really want to use balanced cables to get rid of the interference, but shielded cables would work as well, but I can't find shielded 3.5mm to 2 XLR. The radio station is around 900 (Khz?) give or take, and isn't over a mile or so away. I'm using a Furman power conditioner so I don't think line noise is quite the problem either. The use of balanced cables is a necessity because I do pro audio recording and editing, and all of my components are balanced as well.

dorokusai

Why not use what you did before and just use an RCA to XLR adapter on the end?

What other output choices do you have on the sound card? I'd bet it's not just 1/8 jack.

I'm not sure where you're looking but I didn't find it very difficult to locate shielded mini-jack to XLR cable adapters. Are you just using barrels with headphone cord?

CoolJazz

The 3.5mm TRS jack isn't a balanced output. So if you had advantages in the past from it, it would have been shielded cabling that was helping.

If it's an AM getting in, then the solution is to to bled off the RF with .01 ceramic disc caps to ground. So one each from pin 2 and 3 to pin 1 ground. That forms a low pass on each input pin with RF level stuff being dumped.

CoolJazz

sk1939

dorokusai wrote: »

Why not use what you did before and just use an RCA to XLR adapter on the end?

Well before it was a different pair of monitors with only RCA connection, and an Audigy 2 ZS. Now I'm using the MOTU which has balanced outs and JBLs which have balanced ins. My problem is that I'd like to connect my laptop which only has 1/8" out on it's soundcard.

What other output choices do you have on the sound card? I'd bet it's not just 1/8 jack.

Nope, just 2 1/8" outs on the laptop.

I'm not sure where you're looking but I didn't find it very difficult to locate shielded mini-jack to XLR cable adapters. Are you just using barrels with headphone cord?

It certainly looks like it, it's this thing Cable

sk1939

CoolJazz wrote: »

The 3.5mm TRS jack isn't a balanced output. So if you had advantages in the past from it, it would have been shielded cabling that was helping.

Most likely. I know it isn't a balanced output, but I was using Monster THX shielded cables, but the distance is too far to use them. I don't like to run unbalanced cables for more than 4-6ft.

If it's an AM getting in, then the solution is to to bled off the RF with .01 ceramic disc caps to ground. So one each from pin 2 and 3 to pin 1 ground. That forms a low pass on each input pin with RF level stuff being dumped.

Will that fit in an XLR connector? Why capacitors instead of resistors?

CoolJazz

....

CoolJazz

It's a good idea to keep unbalanced short. But it doesn't mean it won't work.

If you're able to identify an AM station, then if that's the only problem, the LP filtering will fix that. Caps form a LP filter whereas a resistor would just load it, trying to achieve less likelyhood of noise pickup. You could try a resistor but I'd bet on the cap.

Yes, a little .01 disc cap is small enough to go into the connector with care. Keep the leads as short as possible. If you can find a RS with any parts at all, they should still have them.

BTW, examine pin #3 and make sure something is tied to it. It should ideally be tied to the audio ground back at the output end and not tied at the XLR input. If it's left hanging open then you've found a problem to fix. Buying a premade cable, if it is, guarantees nothing.

CJ

sk1939

CoolJazz wrote: »

It's a good idea to keep unbalanced short. But it doesn't mean it won't work.

If you're able to identify an AM station, then if that's the only problem, the LP filtering will fix that. Caps form a LP filter whereas a resistor would just load it, trying to achieve less likelyhood of noise pickup. You could try a resistor but I'd bet on the cap.

Yes, a little .01 disc cap is small enough to go into the connector with care. Keep the leads as short as possible. If you can find a RS with any parts at all, they should still have them.

BTW, examine pin #3 and make sure something is tied to it. It should ideally be tied to the audio ground back at the output end and not tied at the XLR input. If it's left hanging open then you've found a problem to fix. Buying a premade cable, if it is, guarantees nothing.

CJ

Alright, I'll try using the cap and see what happens, our RS still has a few parts left. I cracked open the connector, and to my no surprise, Pin 2 of the XLR connector is hot, while Pin 1 & 3 are tied together neutral/ground.

TECHNOKID

CoolJazz wrote: »

The JBL owner's manual doesn't specify the input impedance of the XLR. However, they do clearly say you can attach -10 inputs to all the connectors, so that would suggest 2 things. 1 - that you have enough gain typically from a -10 input and 2 - the important one, that it's probably a high impedance input.

You don't say much about your noise problem, so it's hard to tell what your trying to correct. But likely you've got noise on the computer output and are simply hearing that. If so, no connector or interfacing is going to correct.

However, the speaker is using a three prong grounded AC input. If they've got that ground tied to the audio ground (pin #1), then you will have a ground loop between the computer and the speaker. So plugging them into different AC sources may give you ground loop issues. Try first plugging the computer and the speakers into the same outlet.

If that's not possible, then you may be able to help yourself by looking at what the 3.5mm to XLR cable is doing. If it's ground is made from the sleeve of the 3.5mm and has continuity to pin 1, then lifting that will keep from having a ground loop. Short as possible wiring is important as well as crossing noise sources at right angles!

If you still have problems, then try to experiment with a small terminating resistance at the XLR. A high impedance input will have a greater likelyhood of "receiving" noise. Terminating it will lower this likelyhood. Try putting about a 10K resistor across pins 2 to 3 and see if that helps.

If this fails, then get a better sound card.

Good luck with it!

CoolJazz

The problem is at the cable it self and that is where the focus should be.

sk1939 wrote: »

Ah, well I'm pretty sure that it's not a ground loop (isolated grounds), but the noise is from what I can hear, an over modulated radio station that comes through occasionally, and for better or worse, the annoying cell phone buzz. I know the speakers are shielded properly, and it's not a sound card issue ( Echo Indigo DJ), because I've never had the problem in the past. The monitors are new, as is the location, and I'm not used to using devices with balanced inputs (previously I was just using just headphones).

When dealing with Balanced/unbalanced connections, the only way out is to use isolation Xfo along with grounding of the unused Lo pin (rarely used with computers).

sk1939 wrote: »

It certainly looks like it, it's this thing Cable

Your above cable would be fine if it were a balanced to balanced connection but in this case is useless. You are actually trying to send a stereo unbalanced signal to a balanced powered speaker and this isn't the proper way to go about it.

What we have to realize is that balanced to unbalanced signal the Lo is generally left opened at the unbalanced side of the cable and acts as an antenna thus the reason for picking-up unwanted noize such as radio stations. You are also right about the difference in signal levels (voltage/db) since the desired level is actually 0 db at the balanced amp (thus the reason to "SOLO/calibrate" each individual I/P & O/P of a mixer at 0 db thus overriding the natural and unavoidable noize of an incoming signal. The use of a stereo passive DI like the one on the below link will surely cure your problem(s) (we use DIs all the time for conferences that have presentations with audio). Talking with one of our Technician (which is also a musician) you probably will not need to use the grounding switch option with your laptop but in any cases, it is there for you to experiment what works best.

http://digiflexcables.com/EN/products.htm

I know it is available in Canada Futureshop is parent company in Canada) so I wonder if available in the US (BB maybe???).
http://www.futureshop.ca/catalog/proddetail.asp?logon=&langid=EN&sku_id=0665000FS10120008&catid=27298#

disneyjoe7

I agree feel it's a cable issue.

CoolJazz

TECHNOKID wrote: »

When dealing with Balanced/unbalanced connections, the only way out is to use isolation Xfo along with grounding of the unused Lo pin (rarely used with computers).

Wrong! Isolation tranformer is probably the best way, but most expensive way. If the speaker is high impedance input with enough gain, then putting a cheap "converter" of any kind in between only decreases quality and doesn't gain a thing!!

TECHNOKID wrote: »

What we have to realize is that balanced to unbalanced signal the Lo is generally left opened at the unbalanced side of the cable and acts as an antenna thus the reason for picking-up unwanted noize such as radio stations.

If the pin #3 has a wire on it going back to the output but isn't tied down, yes that would a problem. But he already said it's grounded.

If you treat it as a balanced input at the XLR, then you still get the common mode reject capability of the balanced input!!! That's the best way to do it without dropping around a $100 each for Jensen's. Avoid cheap converters unless absolutely necessary. Most all of them kind of suck for quality! Throwing a handfull of cheap op-amps and coupling caps in the path just for gain isn't a good solution most of the time!

CoolJazz

TECHNOKID

CoolJazz wrote: »

Wrong! Isolation tranformer is probably the best way, but most expensive way. If the speaker is high impedance input with enough gain, then putting a cheap "converter" of any kind in between only decreases quality and doesn't gain a thing!!


If the pin #3 has a wire on it going back to the output but isn't tied down, yes that would a problem. But he already said it's grounded.

If you treat it as a balanced input at the XLR, then you still get the common mode reject capability of the balanced input!!! That's the best way to do it without dropping around a $100 each for Jensen's. Avoid cheap converters unless absolutely necessary. Most all of them kind of suck for quality! Throwing a handfull of cheap op-amps and coupling caps in the path just for gain isn't a good solution most of the time!

CoolJazz

1. From opening the box my self, I can assure you the boxes use isolation Xfo NO op amp and/or caps!
2. Don't forget the speakers OP is referring to are POWERED speakers therefore the impedance of the speakers has NOTHING to do with it since the interface/isolation box is seen by the amp NOT the speakers. The speakers impedance is seen by the amp ONLY!!!
3. The interface/isolation box provides a switch option for grounding the Lo if need be (however proven unecessary with most computer use).
4. Treating an unbalance signal as balanced by mean of a balance cable doesn't work. Balance circuit doesn't come from the cable but from proper circuitry. The cable is there to carry the signal as originally provided (which is unbalanced in this specific case) the cable will NOT magically balance the signal!
5. Don't forget you are using low voltage/current signal at this stage and do not require massive Xfo and therefore pricing isn't a killer (therefore price doesn't mean cheap but ratter priced according to components that are used: 2 small passive isolation Xfo along with Los going through a switch with gives you the option of grounding them or not). Most of the cost is in the enclosure itself!

Cheers!
TK

CoolJazz

TECHNOKID wrote: »

1. From opening the box my self, I can assure you the boxes use isolation Xfo NO op amp and/or caps!

Cool! Now all you have to be concerned about is the quality of that transformer. But the question remains, why are you putting it there? Galvanic isolation is a good thing, but not at the cost of putting cheap anything there! If it's cheaper than the metal box that it's in, then it's not a quality solution at all!! Not when the situation isn't in need of any impedance change.

TECHNOKID wrote: »

2. Don't forget the speakers OP is referring to are POWERED speakers therefore the impedance of the speakers has NOTHING to do with it since the interface/isolation box is seen by the amp NOT the speakers. The speakers impedance is seen by the amp ONLY!!!

Correct, the amp input impedance is in question. If it was a low input impedance, then the simple computer card line driver wouldn't probably have a ghost of a chance. If it's a high load, then the only thing to worry about is noise pickup. A good shielded cable might get you there, but if he's within a mile of an AM site as mentioned, then the bleeder cap is probably necessary. If it's good enough for the station itself to use, then it's good solution.

TECHNOKID wrote: »

4. Treating an unbalance signal as balanced by mean of a balance cable doesn't work. Balance circuit doesn't come from the cable but from proper circuitry. The cable is there to carry the signal as originally provided (which is unbalanced in this specific case) the cable will NOT magically balance the signal!

You're way off here Techno. The balanced input will provide CMMR as long as you're not tieing it to pin 1 right there in the input connector. Any common mode noise will be rejected that's picked up in between. This is a tried and true method that gets thrown away very often by the use of the RCA/XLR adapter used right at the input.

TECHNOKID wrote: »

5. Don't forget you are using low voltage/current signal at this stage and do not require massive Xfo and therefore pricing isn't a killer (therefore price doesn't mean cheap but ratter priced according to components that are used: 2 small passive isolation Xfo along with Los going through a switch with gives you the option of grounding them or not). Most of the cost is in the enclosure itself!

Pardon me, but I wouldn't consider using anything less than a Jensen, or one of the old Ampex or similar iron. I've used the little tiny xfmr's that RS sold for instance by the boat load for telco interfacing ect, but that's not what you put in for full bandwidth audio! Even something made for stage use probably isn't full bandwidth. Good iron is very overlooked, but going cheap just won't get there in my book!

CoolJazz

TECHNOKID

dO YOU REALIZE THE op IS TALKING ABOUT A PAIR OF POWERED SPEAKERS WORTH SLIGHTLY MORE THAN 300$? Maybe you could also recommend he use MIT interconnects?

The box I am talking about has been used to interface consumer grade electronics (unbalanced) with comercial/profesional grade electronics (balanced) for many years with great success and is therefore proven very effective. Every year, I provide audio visual requirements for our Xmas parties and every time we decided to use laptops to do so, I always used a quality DI box to interface the laptops with the mixer <=> powered speakers with gret success. It did the job, music was great, NO distortion, no ground issue and matched level.

You can prone High End/esoteric interface but don't you think that logic would dictate to use such with High End system?

Below are the specs for the DPI which uses the same for the DSPDI:

Digiflex DPDI - Passive DI Direct Injection Box with Neutrik Jacks - 1/4" Input 1/4" Thru XLR Male Balanced Isolated Output

PROFESSIONAL QUALITY
ROBUST ALL STEEL CONSTRUCTION
Absolutely transparent sound
High-end performance at a fraction of the price
Recessed connectors and switch for mechanical protection
Genuine NEUTRIK® connectors protected by a clamshell design
Designed and engineered in Canada

SPECIFICATIONS
- Freq. response: 10Hz to 40kHz (± 3dB) or 20Hz to 20kHz (± 1dB)
- THD (0dBu) = 0.0137% @ 60Hz; 0.0016% @ 1 kHz; 0.004% @ 20kHz
- Max. input: + 25dBu @ 60Hz (1% THD) - More than enough headroom for any musical instrument
- Dual ¼" connectors at the input with a ground lift switch and a male XLR at the output

These specs are usually only found in very high priced esoteric direct boxes!

http://www.axemusic.com/product.asp?P_ID=19784&strPageHistory=search&strKeywords=digiflex,DSPDI&numPageStartPosition=1&strSearchCriteria=any&PT_ID=all

On page 21 of the below link are some definitions of balance and unbalanced signals, the requirement for common mode impedence:

http://www.jensen-transformers.com/an/Audio%20Transformers%20Chapter.pdf

On the below link, the OP has tried to achieve what is described in 2.1. With the box I have proposed, description of 2.2 is achieved (without the ground switch activated) then as described in 2.3 grounding pin 2 is achieved allowing the I/P stage to drive its + through the O/P Xfo when the ground switch is activated and thus meets all the requirement for proper matching of the unbalanced <=> balanced signal.

http://www.jensen-transformers.com/an/an003.pdf

Page paragraphs 4 & 5 are worht reding also to fully understand CMRR problematics when dealing with unbalanced <=> balanced issues.

Cheers!
TK

CoolJazz

Technokid,

Thanks for taking all the time it took you to find those links. Don't mean to step on your toes for something that your obviously happy with. If it works, it works. And yes, I do have trouble scaling back. But he probably would hear a nice improvement with MIT cables... But your right, that'd be above and beyond.

But I'd suggest being careful about thinking regarding those specs that they accomplished more than the experts like Jensen have been able to do. But I do like the idea of transformers...just not needed in this case, cheap or not.

I stand by that if there is RF, the long time traditional RF bleeder cap is simple and very effective.

The balanced/unbalanced interfacing does have several issues to it. Buying a simple adapter may work or may not. And may or may not be the best answer. For instance the running a cheap RCA cable over a distance and then using the adapter right at the XLR input can work fine. But won't have the common mode rejection advantage. But if there isn't noise, then that wouldn't matter, would it? The OP does have noise...apparently from RF.

CoolJazz

sk1939

CoolJazz wrote: »

Technokid,

Thanks for taking all the time it took you to find those links. Don't mean to step on your toes for something that your obviously happy with. If it works, it works. And yes, I do have trouble scaling back. But he probably would hear a nice improvement with MIT cables... But your right, that'd be above and beyond.

But I'd suggest being careful about thinking regarding those specs that they accomplished more than the experts like Jensen have been able to do. But I do like the idea of transformers...just not needed in this case, cheap or not.

I stand by that if there is RF, the long time traditional RF bleeder cap is simple and very effective.

The balanced/unbalanced interfacing does have several issues to it. Buying a simple adapter may work or may not. And may or may not be the best answer. For instance the running a cheap RCA cable over a distance and then using the adapter right at the XLR input can work fine. But won't have the common mode rejection advantage. But if there isn't noise, then that wouldn't matter, would it? The OP does have noise...apparently from RF.

CoolJazz

LOL, so much reading to do.

I do own a pair of DI boxes (cheap ones) for my electric guitars, but the problem is that they do hinder audio quality, something I cannot afford when editing/mixing orchestral music. I have not looked at higher end ones, or active DI boxes, so I'll take a look later. As far as the radio noise issue, I went out and bought a pair of these RF filters to use for the AM problem, seems to work fine.

As far as the balanced line problem, I would use RCA in's but you have to realize also that my REL sub is connected to the monitors as well with an XLR Y adapter (the REL is using a Speakon to XLR adapter), so that's something else to be aware of. As far as cabling, everything balanced is using Mogami balanced cables.

As far as my speakers go, I will have you know that while not alot, they are $600 for the pair, and the sub is another $600. I am up at school remember, so taking my LSR 4326's would be foolish indeed.

This is giving me such problems that I just may go from the laptop into the MOTU's USB port (desktop which I use primarily, is connected via Firewire), and not have to worry about it all.

sk1939

I did find out that the XLR connection can accept a line level input as long as Pin 2 is hot, but again, that defeats the purpose of having balanced connections.

Oh and as a side note, the speakers don't sound like their cost, they sound much better (I've compared them).

CoolJazz

SK, I've never seen that particular Shure RFI fixer connector, but it's spot on for the AM issue. It's the $35 each version of what I was suggesting for less than a buck or two. But you avoided the need for soldering iron etc.

I'm not sure exactly what you're saying about pin 2 hot. If you only have the single hot lead then it's obviously not balanced audio. But yes, it's absolutely the case that if you wire the input like it's balanced, then the common mode reject is present regardless of whether the low side is inverse audio or simply tied back to the sources ground. The only thing needed to do that is NOT tieing the low pin to ground at the input. Still has to be grounded, just do it at the source not at the input. Down side is half the level of balanced and therefore that much closer to the noise floor. A trick that works well!!

The reason to use iron is to isolate, impedance match and perhaps change gain, though that gets dicey (read $$ to do right) quick.

CJ

PS...I'm sure you temporarily pulled out that sub Y to make sure it's not causing issues! Particularly where it pulls power ground!

sk1939

CoolJazz wrote: »

SK, I've never seen that particular Shure RFI fixer connector, but it's spot on for the AM issue. It's the $35 each version of what I was suggesting for less than a buck or two. But you avoided the need for soldering iron etc.

I'm not sure exactly what you're saying about pin 2 hot. If you only have the single hot lead then it's obviously not balanced audio. But yes, it's absolutely the case that if you wire the input like it's balanced, then the common mode reject is present regardless of whether the low side is inverse audio or simply tied back to the sources ground. The only thing needed to do that is NOT tieing the low pin to ground at the input. Still has to be grounded, just do it at the source not at the input. Down side is half the level of balanced and therefore that much closer to the noise floor. A trick that works well!!

The reason to use iron is to isolate, impedance match and perhaps change gain, though that gets dicey (read $$ to do right) quick.

CJ

PS...I'm sure you temporarily pulled out that sub Y to make sure it's not causing issues! Particularly where it pulls power ground!

I did try that, pulling the sub Y...it's a nightmare cable setup that I'm sure will give me problems/interference later on, but so far nothing.

As far as pin 2 hot, the manual states that if you use unbalanced inputs on the balanced XLR input, it says "pin 2 must be + to have foward cone movement" or something to that extent. I think that I'll just tie everything into a mixer or the MOTU and be done with it, it's just not worth the headache to keep worrying about the impedences and voltage and whatnot. The MOTU is balanced out, JBL's are balanced in, the REL is Speakon HI-Z but that different.

Impedence matching transformer huh, something like this?

CoolJazz

That's a $75 fix for a problem that I'm not so sure you have. You say headache...it's not one if you hook it up, it works and you just move on. Don't over think it. Putting an extra stage of anything in comes with sonic costs. If you don't need it, its a cost that doesn't pay.

CoolJazz

sk1939

CoolJazz wrote: »

That's a $75 fix for a problem that I'm not so sure you have. You say headache...it's not one if you hook it up, it works and you just move on. Don't over think it. Putting an extra stage of anything in comes with sonic costs. If you don't need it, its a cost that doesn't pay.

CoolJazz

I did hook it up, and it does work (3.5mm to 2 XLR), there's just an annoying hissing that sounds occasionally when using the built in sound card rather than the external (computers bad ground I'm sure). The levels are slightly strange, but it does work, and the knob is 1/4 of the possible volume and it is plenty loud. The nice thing about monitors is that when they say 50W, they mean 50W, these things get ear splittingly loud. The nice thing about monitors is that they have a large sweetspot (at least these do), no matter where you are in the room, assuming there's nothing in the way, the monitors sound just as good as they do up close.