Confused between studio monitors for HT setup

[TimW]

I understand why someone would buy a Denon AVR just for use as a pre/pro since they have a great price to performance ratio. But why would you want powered studio monitors for a surround sound system? You already get decent amplification with the Denon, certainly on par with most affordable studio monitors. And you can get passive speakers with great performance at a reasonable cost from the likes of JBL, Infinity, ELAC, Focal, KEF, etc.

Plus studio monitors aren't well suited for surround sound system use. They have balanced inputs that need adapter cables and they all require power as well. Then you've got to figure out how you're going to turn them all on and off. I had an LSR305 surround sound system for a little while and they're hiss was very annoying when nothing was playing. Would not recommend a system like that.

 

[AnalogSteph]

Yes, the DI box can be very very close to AVR.

I meant exactly the opposite - close to the speaker.

 

[LTig]

I meant exactly the opposite - close to the speaker.

That makes no sense, IMHO.

 

[Hifisound]

I understand why someone would buy a Denon AVR just for use as a pre/pro since they have a great price to performance ratio. But why would you want powered studio monitors for a surround sound system? You already get decent amplification with the Denon, certainly on par with most affordable studio monitors. And you can get passive speakers with great performance at a reasonable cost from the likes of JBL, Infinity, ELAC, Focal, KEF, etc.

Plus studio monitors aren't well suited for surround sound system use. They have balanced inputs that need adapter cables and they all require power as well. Then you've got to figure out how you're going to turn them all on and off. I had an LSR305 surround sound system for a little while and they're hiss was very annoying when nothing was playing. Would not recommend a system like that.

The reason I got LSR308 was they were even cheaper than Elac B6.2 here in India. Yaa turning them on is one hassle but I expect better SPL handling from them in my 22’ x 14’ ft room. I tested them and didn’t find the hiss to be an issue unless listening very close to the tweeter.

( for 4 atmos I plan to use passives)

 

[FrantzM]

Hi

In my HT, Music is through headphones, > 98%
I have a room of similar size... concrete with windows sometimes, open.
3 JBL LSR 308 for LCR
2 JBL LSR 305 for Surround
2 Bose 161 for Atmos speakers
3 Parts Express Sub 1500.
1 Denon AVR X-3400

I hear no hiss. I have reached, on Aquaman 108 dB at the LP before lowering the volume, I should have worn earplugs,. I sit about 11 ft from the LCR/screen and 8 feet from the surrounds...
I hope I am not jinxing myself, m DIY Cables made of TRS to RCA . Belden 8241 Coax, no Hum either.
Quite pleased by this system. Event content ... but ..... being an audiophile, may move in a few month (sight unseen) toward JBL SRX 835P, 815P and 3 SRX 828 Subwoofers... Yep! I am an audiophile. A nutcase.

 

[AnalogSteph]

That makes no sense, IMHO.

Why? Cable (+ input) capacitance is critical on the output side of a transformer, where there is just the >10 kOhm input impedance in parallel. You don't want the ultrasonic resonance peak to be shifted too much into the audible range.
On the input side, it's seeing the very low-impedance source output instead (much heavier damping in the RLC), so the cable can be much longer without any ill effect. It should be some decent coax, of course, which will give good shielding and have low capacitance to boot. (The output side goes into a balanced input, so some ordinary twisted pair there.)

Yes, the overriding concern is the transformer.

I wouldn't dare a prediction on interference rejection for different percentages of unbalanced vs. balanced cabling, but wouldn't expect any major issues either way. The Monoprice cable should generally be fine, too, but I would not rule out that certain combinations of cable length and ground loop area couldn't get enough ground loop current going to cause an audible issue in the AVR.

 

[LTig]

Why? Cable (+ input) capacitance is critical on the output side of a transformer, where there is just the >10 kOhm input impedance in parallel. You don't want the ultrasonic resonance peak to be shifted too much into the audible range.
On the input side, it's seeing the very low-impedance source output instead (much heavier damping in the RLC), so the cable can be much longer without any ill effect. It should be some decent coax, of course, which will give good shielding and have low capacitance to boot. (The output side goes into a balanced input, so some ordinary twisted pair there.)

Yes, the overriding concern is the transformer.

I wouldn't dare a prediction on interference rejection for different percentages of unbalanced vs. balanced cabling, but wouldn't expect any major issues either way. The Monoprice cable should generally be fine, too, but I would not rule out that certain combinations of cable length and ground loop area couldn't get enough ground loop current going to cause an audible issue in the AVR.

I always thought that DI boxes are made for stages, where the connection to the unbalanced source is much shorter than the connection to the balanced sink - could be a mixing console through 25 m or more of multicore cable. And it makes sense to keep the unbalanced connection as short as possible because all noise inducted into it cannot be separated from the signal. Of course there are active DI boxes which do not suffer from transformer problems because they don't have one.

 

[AnalogSteph]

I always thought that DI boxes are made for stages, where the connection to the unbalanced source is much shorter than the connection to the balanced sink - could be a mixing console through 25 m or more of multicore cable. And it makes sense to keep the unbalanced connection as short as possible because all noise inducted into it cannot be separated from the signal. Of course there are active DI boxes which do not suffer from transformer problems because they don't have one.

When I hear DI box, I'm thinking recording studio as early as Beatles era, but whatever. What I know about DI boxes is mostly from Wikipedia, so I would hesitate to call myself an expert on the matter.

As a not unimportant distinction though, what we are talking about in this application is a line-level transformer, not a DI box. The two are commonly conflated (it's a box with a transformer inside that converts balanced to unbalanced), but the important distinction is that a DI box uses a transformer with a non-1:1 turns ratio to perform an impedance transformation - high level, high impedance pickup signal to lower-level, nominal 200 ohm microphone impedance. The high-impedance input side (the pickup isn't helping that much) would be the more critical one in this case.

In case of the Radial Eng. JDI, for example, input impedance is 140 kOhms, while output impedance is 150 ohms. The Jensen JT-DB-EPC transformer datasheet reveals that it's a 12:1 transformer and that the 140k input impedance spec actually assumes 1 kOhm output loading, so actual input impedance with typical 2-3 kOhm mic inputs is likely to be higher. Signal voltage is being reduced by a factor of 12 (21.6 dB), while current goes up by the same factor.

In comparison to a 600 ohm in/out or even 10 kOhm in/out line-level transformer, the 200 ohm output side of a DI transformer has lower inductance to begin with and is loaded with a typical 2-3 kOhm mic input to boot, so it would in fact support a substantially longer run of cable without undue FR peaking. Also, a 12:1 turns ratio means that 144 pF of cable capacitance on the output (that's about 1 m of twisted pair) is being transformed to just 1 pF on the input side (about 1 cm of coax).

Some active DIs do not even provide galvanic isolation either.

 

[Hifisound]

The cable dealer has recommended me this for the rear speakers which require 37 ft length
https://dbxpro.com/en/products/djdi

this is passive though

 

[AnalogSteph]

The cable dealer has recommended me this for the rear speakers which require 37 ft length
https://dbxpro.com/en/products/djdi

this is passive though

From the specs:

Insertion Loss 21dB typical

So that's how they're getting from 50k to 600 ohm nominal. Seems a bit much though, unless you have a fairly hot output to run into it. You may be able to spare 10 dB but not this much.

I'd say stick with the HD400, that's got like 1-2 dB worth of insertion loss tops. It's a nominal 600:600 ohm, so not the easiest load perhaps, but it'll drive some cable length at least, I just wouldn't overdo it.

 

[Hifisound]

From the specs:

So that's how they're getting from 50k to 600 ohm nominal. Seems a bit much though, unless you have a fairly hot output to run into it. You may be able to spare 10 dB but not this much.

I'd say stick with the HD400, that's got like 1-2 dB worth of insertion loss tops. It's a nominal 600:600 ohm, so not the easiest load perhaps, but it'll drive some cable length at least, I just wouldn't overdo it.

Thx.

Will an active one be better ? Or will it be more noisy ?
I am also wondering if I should use active DI for all 5 LSR308s ( even for nearer LCRs) to have better gain match between AVR pre out and 308s