The catch
Onkyo TX-RZ30
Even with more amplifiers, nine-channel processing rules out a 7.1.4 expansion.
Side by side
Onkyo TX-RZ30 vs Denon AVR-X3900H: Onkyo comes with Dirac, Denon can grow to 7.1.4 and four separate subs
Quick verdict
TX-RZ30 is the pick for a settled nine-speaker room that should come with full-bandwidth Dirac Live. If you plan to grow to 7.1.4 or connect four subwoofers separately, AVR-X3900H is the pick. Preferring Dirac to the included Audyssey setup means paying for a Dirac license on the Denon.
Before you buy
Why, and what it costs you
Only the Denon expansion is solved by an external amp
Eleven main channels make up a 7.1.4 layout. Denon can process all eleven and needs two additional amplifier channels. Onkyo is missing those two processing channels, so an amp on its own cannot complete the same layout.
Where this comes from
7 + 4 = 11. X3900H: 11 processed - 9 amplified = 2 external channels. RZ30: 9 processed, which leaves 2 channels unavailable before amplification even comes into it.
The catch
Denon AVR-X3900H
Dirac Live is an added cost on top of the receiver.
Onkyo TX-RZ30
- Why pick it
- Full-bandwidth Dirac comes included while you run 5.1.4
- You skip buying a separate Room Correction license
- The catch
- Even with more amplifiers, nine-channel processing rules out a 7.1.4 expansion.
Denon AVR-X3900H
- Why pick it
- You want a documented route to 7.1.4 using an external amp
- Four subwoofers need to be independently adjustable
- The catch
- Dirac Live is an added cost on top of the receiver.
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What this page compares
Onkyo TX-RZ30 vs Denon AVR-X3900H on included Dirac, 5.1.4 speakers and later 7.1.4 expansion, plus which receiver spares you the next upgrade.
TX-RZ30 is the pick for a settled nine-speaker room that should come with full-bandwidth Dirac Live. If you plan to grow to 7.1.4 or connect four subwoofers separately, AVR-X3900H is the pick. Preferring Dirac to the included Audyssey setup means paying for a Dirac license on the Denon.
Which one fits
Pick the situations that sound like you
My room stays at 5.1.4, and I want Dirac
The full-bandwidth Room Correction license comes with Onkyo. For Denon it is an optional purchase.
- Onkyo TX-RZ30
- Better fit
- Denon AVR-X3900H
- Good
I might put rear surrounds into a 5.1.4 room
That makes it 7.1.4. Denon can process it given two external amplifier channels, whereas Onkyo tops out at nine.
- Onkyo TX-RZ30
- Not suitable
- Denon AVR-X3900H
- Good
I want four subwoofers, each with its own connection
Four independent sub outputs are on Denon. Onkyo has two outputs.
- Onkyo TX-RZ30
- Not suitable
- Denon AVR-X3900H
- Better fit
I need room for six high-frame-rate HDMI sources
Six 4K120-capable inputs are listed for each, though the exact formats matter. Onkyo inputs 4 to 6 are limited to 24 Gbps, so check the source format and DSC requirements.
- Onkyo TX-RZ30
- Depends
- Denon AVR-X3900H
- Depends
In practice
Differences you will notice
Only the Denon expansion is solved by an external amp
Eleven main channels make up a 7.1.4 layout. Denon can process all eleven and needs two additional amplifier channels. Onkyo is missing those two processing channels, so an amp on its own cannot complete the same layout.
How we worked this out
7 + 4 = 11. X3900H: 11 processed - 9 amplified = 2 external channels. RZ30: 9 processed, which leaves 2 channels unavailable before amplification even comes into it.
At 5.1.4, the software that is included starts to matter
Each receiver already powers the nine speakers of 5.1.4. If that is your final layout and Dirac is something you specifically want, RZ30 comes with the full-bandwidth Room Correction license that Denon sells separately.
How we worked this out
5 + 4 = 9 main channels. Each has 9 amplifiers. Onkyo documents a full-bandwidth Dirac Live Room Correction license as included, and Denon lists Dirac as an optional upgrade.
Four independent connections are needed for a four-subwoofer plan
X3900H can give four subs their own outputs, but RZ30 has two. Splitting two outputs may feed more physical subwoofers, yet it does not create four receiver outputs that are independently controlled.
How we worked this out
X3900H specifies 4 independent subwoofer outputs, and RZ30 provides 2. A passive splitter copies a signal and does not add receiver processing outputs.
Plan your receiver connectionsLay out my system
Check a documented speaker layout against HDMI sources and external-amplifier plans.
Onkyo TX-RZ30
Handles your setup
Runs 5.1.2 on its own built-in amplifiers. Takes 3 HDMI devices, 1 of them at 4K/120Hz. Input count does not guarantee every chroma, bit-depth or DSC combination. Check the manufacturer's HDMI format table and current firmware.
Denon AVR-X3900H
Handles your setup
Runs 5.1.2 on its own built-in amplifiers. Takes 3 HDMI devices, 1 of them at 4K/120Hz.
A powered subwoofer does not count toward the speaker channels. This checks one main room. Check Zone 2, bi-amping and unusual speaker assignments yourself. Leave room for ventilation, and confirm HDMI settings, cables and speaker impedance before you install.
Option A
Onkyo, TX-RZ30
TX-RZ30
Full-range pre-outs and a full-bandwidth Dirac Live license come with this nine-channel receiver. It fits a 5.1.4 system that might use external amplifiers, though that adds no processing channels.
- Best for
- Dirac on nine channels, with power-amp flexibility
Facts we checked
- Built-in amplifiers: 9
- Main processing channels: 9
- Included calibration: Dirac Live Room Correction Full Bandwidth
- Subwoofer connections: 2 outputs
Option B
Denon, AVR-X3900H
AVR-X3900H
You can run 5.1.4 today on the nine built-in amplifiers and eleven-channel processing, then reach 7.1.4 by adding an external stereo amp. Four independent sub outputs make a more involved bass setup possible.
- Best for
- Growing from 5.1.4 to 7.1.4 in stages
Facts we checked
- Built-in amplifiers: 9
- Main processing channels: 11
- Included calibration: Audyssey MultEQ XT32
- Subwoofer connections: 4 independent outputs
Spec by spec
Where they really differ
| Spec | Onkyo TX-RZ30 | Denon AVR-X3900H | In practice |
|---|---|---|---|
| Built-in amplifiers | 9 | 9 | A five-speaker base layer with four heights can be powered by either. |
| Main processing channels | 9 | 11 | Denon alone can process the eleven main channels that 7.1.4 requires. |
| Included calibration | Dirac Live Room Correction Full Bandwidth | Audyssey MultEQ XT32 | The setup workflow that comes included is different. Denon offers a paid Dirac route. |
| Subwoofer connections | 2 outputs | 4 independent outputs | Four separate subwoofer connections on Denon need no split signal. |
| HDMI input count | 6, with three 40 Gbps and three 24 Gbps inputs | 6, all supporting 4K120 within the published format limits | Lower bandwidth applies to Onkyo inputs 4 to 6. For each source, check chroma, bit depth and DSC requirements. |
| Main-channel pre-outs | 9 | 11 | How many pre-outs there are depends on each receiver's processing limit. |
Trade-offs
What each pick costs you
With Onkyo TX-RZ30
- Dirac Bass Control is optional and sits apart from the included Room Correction license.
With Denon AVR-X3900H
- 7.1.4 continues to need two external amplifier channels.
Change of plan
When the answer changes
The receiver has to include full-bandwidth Dirac
Go with Onkyo TX-RZ30. Room Correction comes with RZ30. Bass Control is still optional.
Later on I plan an eleven-speaker main room
Go with Denon AVR-X3900H. Eleven-channel processing and the external-amplifier connection path are supported by X3900H.
I need 7.1.4 and want no external amplifier at all
Neither model fits. Nine built-in amplifier channels are in each.
Decision guide
How to decide
A settled nine-speaker room that wants full-bandwidth Dirac Live included belongs with TX-RZ30. Plans to reach 7.1.4 or to connect four subwoofers separately belong with AVR-X3900H. On the Denon, preferring Dirac over the included Audyssey setup means buying a Dirac license.
Work out if nine speakers is the finish line
RZ30 has a straightforward case in a settled 5.1.4 room, particularly if Dirac is the calibration system you want to learn. If two rear surrounds are likely to come later, the Denon saves you from replacing the receiver, though you would still need the extra speakers and two amplifier channels.
Treat the Dirac products as distinct
Full-bandwidth Room Correction is covered by the license included with the Onkyo, while Bass Control is an optional addition. The word Dirac does not promise that every bass-management tool is included. For the Denon, check the exact license and the cost of a compatible microphone before comparing total prices.
Spare terminals count for less than extra processing
A rear panel may look ready for many speakers even though the receiver processes fewer channels at once. When planning an expansion, check processing, amplification and pre-outs together. With an external amp, the Denon combination supports eleven main channels. The Onkyo combination stays a nine-channel system.
What this page can’t tell you
- What you have here is a review of US connections and speaker layouts. We did not measure amplifier output, room-correction results or sound quality. Checking HDMI format, firmware and display compatibility is still up to you.
By the numbers
What the data shows
What we found across the AV receivers we compare, plus the checked facts behind each finding.
Show the facts and the math
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| Onkyo TX-RZ30 |
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| Denon AVR-X3900H |
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Ready to buy
See today’s price and what owners say
Open either model on Amazon for the current price, customer reviews and delivery options.
Onkyo TX-RZ30
Full-bandwidth Dirac comes included while you run 5.1.4
See price & reviews on AmazonDenon AVR-X3900H
You want a documented route to 7.1.4 using an external amp
See price & reviews on AmazonEach link opens in a new tab.
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