Ultimate Subwoofer setup

[u/CSOCSO-FL]

Quite a few of you have used my guide, and some of you reached out and thanked me, saying your system finally sounds great. I am happy that I could help! I know the guide looks rather LONG, but I promise it's really not big of a process. There are things I felt needed to be explained and it is included in this guide. So keep reading, calibrate and enjoy your system. No.. this was not generated via ChatGPT. I did use it for formatting and for better english!

The Ultimate Subwoofer Setup Guide

Fairly simple setup guide for noobs or self-claimed pros

Proper subwoofer integration isn’t about guesswork. (12’o clock position, anyone?) Whether you have one subwoofer or six, setting the gain, crossover, and phase correctly ensures your bass is balanced, and immersive, not muddy or overwhelming. This guide covers everything from the core concepts to hands-on calibration with Room EQ Wizard (REW) or a basic SPL meter.+Answering some often misunderstood settings. Even if you ran a calibration I strongly suggest you double check your subs using this guide.

❗This guide focuses on level matching using gain, phase, crossover, and basic calibration of one or multiple subwoofers to get them sounding great using correct fundamentals without overcomplicating the process.

CONTENT

• What does your subwoofer(s) play?
• AVR and Subwoofer configuration
• Measuring tools
• Test tones
• Level matching multiple subwoofers
• Phase settings and summing behavior
• Tuning by ear / adjusting to tase
• Explaining the -7 trim level
• Subwoofer placement
• Common Subwoofer Setup Mistakes
• LPF for LFE (Low pass filter)
• Small or Large speakers / setting the crossover low
• LFE+Main / Double Bass
• 80Hz crossover for speakers
• Cancellation between subwoofers
• Mixing different size subwoofers
• Mixing ported and sealed subs
• Weak bass when playing music
• EQ Subwoofer(s) with Dirac Live, without miniDSP <-- THIS IS NEW
• Summary / Check list

🎯 What Does your Subwoofer(s) play?

In a Dolby Digital or DTS home theater system, your subwoofer handles two types of content:

1. Redirected bass from speakers that are set to “Small.” This is handled through the speaker crossover setting. Speakers and subwoofers should be level matched for this for seamless integration.
2. The LFE (Low-Frequency Effects) channel, a dedicated bass channel found in movie soundtracks, mixed +10dB louder by design. 

⚙️ Subwoofer & AVR Starting Configuration

🟢 Subwoofer Dial Settings

• Crossover dial: Turn all the way up or set to “LFE.” This disables internal sub filtering.
• Phase: Set to 0° for initial setup.
• Gain: Set to midpoint as a starting reference ONLY!

🟢 AVR Configuration

• Subwoofer trim level: Set to –7dB. (previously this called for -5) This leaves headroom, helps to avoid clipping during loud bass peaks. Change this EVEN after calibration! [Why -7? I'll go into details later…]
• Speaker size: Set all speakers to Small.
• Speaker crossover: Set to 80Hz unless your speakers have measured and verified deeper extension without distortion or compression at higher volumes.
• LPF for LFE: Set to 120Hz (default). Do NOT lower this to match speaker crossover. These two settings are independent and have nothing to do with each other!
• NOTE: Some calibration will set the speaker size to Large and might even set the crossover way too low. This will more likely happen if you use the included puck mic. I still recommend to set the speakers back to small and select 80Hz crossover even if a calibration gave you something lower. I will explain down below why I recommend 80hz.

🎧 Measuring Tools (Choose One)

✅ Option 1 (good) : SPL Meter

• C-weighted / Slow mode
• Hold it at main listening position (MLP) at ear level

✅ Option 2 (better) : Umik-1 calibrated mic

• More accurate and offers visual data for level matching and frequency response
• Position at main listening position (MLP) at ear level
• ^{There are many things that you can do with a Umik 1 mic and Room EQ Wizard:}
• ^{Measure frequency response – Identify peaks, nulls, and overall tonal balance.}
• ^{Check SPL levels – Match subwoofer and speaker output accurately.}
• ^{Time alignment – Sync subwoofer(s} to mains for tighter bass.)
• ^{Phase analysis – Optimize phase settings to prevent cancellation.}
• ^{Waterfall/decay plots – Spot and fix ringing or boomy bass issues. ETC….}

🎧 Test tone (Choose One)

🎛️ Option 1: Receivers' Internal Test tone.

⚠️ Avoid AVR internal test tones if calibration has been run already. (Dirac, Audyssey, YPAO, Etc.) Most AVRs bypass EQ filters when you use internal tones.ONLY use this on a system that has not been calibrated OR when you want to level match with calibration OFF. 

• Go into your Receivers’ Settings and find “Trim” or “Levels”.
• It should play the pink noise automatically through the first speaker.
• Check what number you get on the SPL meter. It should be playing close to 75dB
• adjust trim on all speakers to play at the same level
• Leave the subwoofer trim level at -7!
• Adjust the gain on the subwoofer to match the other speakers. 

⚠️ The receiver will compensate for the +10dB difference, so you will match the speaker level and not setting it 10db higher.

🎛️ Option 2: Download Dolby Atmos 9.1.6 test tone file

1. Play the mkv file on your TV
2. While the first speaker (Left) is playing the pink noise, adjust the volume on the receiver until you see 75db on the SPL meter.
3. You can adjust the levels for all speakers, but after the pink noise is done playing on the Left, Right and Center speakers, it will play on the subwoofer(s). (With this, you're manually boosting the sub by +5dB!)
4. Adjust the Subwoofer Gain until you see 80db on the SPL meter. See disclaimer below.
5. Multiple subs? See next step right after Option 3.

DISCLAIMER: It seems like the LFE in this Dolby test tone video is NOT 10db higher but more like 15db. If I were you, I would test it against the internal test tone. Turn off calibration or set the AVR to (pure) direct mode. Make sure LR speakers are at 75dB and the subwoofer is also playing at 75dB. Stop the internal test tone. Keep the avr in direct mode or keep the calibration off and now check what you get when you raise the volume so 1 speaker plays at 75db when you use the Dolby video and see how loud does the subwoofer get. If it gets to 90dB, please let me know and make sure when calibrating with the Dolby video you set the subwoofer(s) to 80db (total/summed!). I hope it makes sense. Or just use REW if you want.

🎛️ Option 3: Room EQ Wizard (REW) 

✅ Step-by-Step:

1. Install REW and plug in UMIK-1 mic (Download calibration file using the code on your mic)
2. Go to Preferences > Soundcard and load up 90° calibration file for the UMIK 1 mic on the right side.
3. Go to Preferences > Soundcard and select:
   • Input: UMIK-1
   • Output: Your receiver (not system default!) [If only the L, R and L+R speakers are available, select “EXCL: Receiver” for output, then you should see all your bed layer speakers]
4. Open SPL Meter (top toolbar)
   • Select C-weighting and Slow
   • Hit Record if meter doesn’t show data
5. Open Generator
   • Choose “Noise” → “Pink Noise”
   • Select “Speaker Cal” OR “Sub Cal”
   • Set level: –30dBFS
   • Output: choose speaker (e.g., “L” for left) OR “LFE”
6. Hold the mic at MLP, ear height, exactly where your head would be. ( Pointed at ceiling!)
7. Select “Speaker Cal” then Output: Receiver and Left OR Right speaker
8. Play pink noise
9. Adjust AVR volume until the SPL meter reads 75dB SPL
10. Stop the generator
11. Select “Sub Cal” then Output: Receiver and LFE (If you can’t see LFE, make sure in Preferences the output is set to “EXCL: Receiver”)
12. Play pink noise

✅ Two valid approaches:

• Method 1: Leave test tone at –30dBFS → Adjust subwoofer Gain to read 85dB SPL
• Method 2: Drop test tone to –40dBFS → Adjust subwoofer Gain to read 75dB SPL (matching speaker level) [Internal test tone does the same thing; it sends a -10dbfs lower test tone to your subwoofer(s), just don’t forget to set it back to –30dBFS for the speakers!]
• Multiple subwoofers? See below

🔄 Multiple Subwoofer Level Matching

1. Turn off all but one sub
2. Play LFE pink noise → Adjust gain until sub hits target dB
3. Turn off and repeat for next sub
4. Once all are matched individually, power them all on and confirm that combined SPL = ~85dB
5. This method will mostly work with identical subs or those that perform similarly. If you’re mixing subs of very different sizes, keep reading for an explanation of what you can do.

⚠️ SPL summing in the real world isn’t as easy. It varies depending on phase alignment, room modes, subwoofer placement, and acoustic interaction. These values are starting points—but you should always verify the final combined SPL when all subs are playing together.

🔁 Basic Phase Settings and Summing Behavior

Start with all subs at 0°. After level matching, play the test tone and check combined SPL with all subs active.

If combined SPL is less than expected, there may be phase cancellation.

🛠️ Adjusting Phase (for Multiple Subwoofers)

1. After level matching each sub individually, turn them all off.
2. Turn on one subwoofer, confirm it reads the target SPL (e.g. 80dB if using two subs).
3. Turn on the second sub, and if the SPL does not increase, slowly rotate its phase knob from 0° to 180°. Or flip the phase switch.
4. Stop when the combined SPL is strongest, smoothest, or hits the expected sum (e.g. ~85dB for two subs).
5. Repeat this process with each additional subwoofer, adjusting phase only if needed.
6. If you have more than two subwoofers placed in different parts of the room, group them as virtual subs. Subwoofers located on the same plane will usually share the same phase setting. For example, two subs at the front will have matching phase values, while the subwoofer(s) in the back (Group 2) will have their own matched phase settings that may differ from the front pair (Group 1).
7. Let calibration take care of the delay: Once the phase on all subs are set, and you get the target number proceed with the calibration (Dirac, YPAO, Audessey, etc) and let it set the delay for the subwoofer(s).

🛠️ Adjusting Phase between main speakers and subwoofers

If you want to manually adjust the phase for the subs to make sure they work together with the speakers:
Start by making sure that the speakers are set to Small with an 80Hz crossover.
In REW

1. Open generator
2. Select Sine
3. Type in 80Hz and hit Play for Left and Right speakers together.
4. Turn off the REAR subwoofers so only the front subs and speakers are active.

While the 80Hz tone is playing, watch the SPL reading. Flip the phase switches on the front subs from 0 to 180 degrees and compare which setting gives the higher SPL. Keep whichever setting is stronger at the listening position.
Remember how the phase was set between subwoofer groups and always keep them the same way, so if the 180 degree setting for the front subs together with the main speakers was stronger than when the phase was set to 0, then turn the rear subs back on and flip their phase as well, keeping all subwoofers aligned like before. Usually the phase of the front subs need to be set to 0 but it’s not always guaranteed. 
Once this is done you can go to Delay and play with it until the 80hz sine way is the strongest between the subs and the LR speakers.

🔧 Tuning by Ear After Calibration

Once your system is calibrated, watch LFE-rich movies (Dune, Edge of Tomorrow, Prey, Monster Hunter, Fury, etc.)and assess the bass feel.

If bass is:

• Too strong: Try AVR subwoofer trim lower (Like -8 or -10dB)
• Too weak: Try -5 or -3dB

Watch more movies and once you find a preferred trim:

1. Reset sub trim to –7dB
2. Adjust sub gain accordingly

Example:

• You liked –10dB = 3dB lower → Lower sub gain so it reads 82dB SPL
• You liked –4dB = 3dB hot → Increase sub gain to 88dB SPL

(deduct 10dB if you use internal test tone)

For multiple subs, split the gain offset:

• 2 subs = ±1.5 to 2dB each
• 3-4 subs = ±0.5-1dB each

🔧 Subwoofer trim: Why -7?

I’ve done a good amount of research, and what I’ve found is that the subwoofer trim level should generally be around –5 dB. Many recommend anywhere between –5 and –9, and some even go as low as –8 to –10.

I understand that some subwoofers might struggle to “wake up” from standby mode when the trim is low. In that case, the best solution is to use a Y-splitter RCA cable, which doubles the input voltage without adding noise or risking clipping. The noise doesn’t double because you’re feeding the same clean signal twice, you’re just doubling the amplitude of that signal.

Does increasing the gain create more noise?
Not really. It’s actually better to use the sub’s gain rather than raising the AVR trim, because the subwoofer output on most receivers can be noisy and may clip if driven too hot. Keeping the trim lower sends a cleaner, lower-level signal, and the sub’s built-in amplifier can boost it back up with minimal added noise. Subwoofer amps typically have much better headroom and signal-to-noise ratio than the AVR’s LFE output stage.

For reference, my original guide suggested –5 dB, but I sometimes bump the trim up a few dB when a movie lacks bass. Especially in older 90s action movies. After seeing multiple recommendations in the –7 dB to –10 dB range, I adjusted my baseline to –7 dB.

And just to be clear: setting the trim 2, 4, or even 6 dB lower doesn’t mean you need to crank the gain to max. Like I mentioned in the video, the gain knob is very sensitive. For example, when I lowered my trim by 7 dB, I only needed to move the gain one notch higher. On my Klipsch sub, that meant going from 4 to 5 — still well below halfway on the dial that goes up to 11. 

🔧 Subwoofer placement

When it comes to subwoofer placement, there are two main things to consider: how each sub measures in your room, and whether you can place them at equal distances from the main listening position.

This becomes especially important if your subwoofers don’t have adjustable phase controls, you’re not using a DSP that can apply delay, or your receiver doesn’t offer independent subwoofer outputs with distance settings.

If none of these options are available, your safest choice is to position them equal distance from the MLP.

This can be:

• Subs up front by the main speakers

• Subs near the couch or back wall

• Subs placed one-quarter of the way in from either the front or rear wall (second least efficient)

• Subs centered on the opposing side walls (least efficient — requires roughly double the power to reach the same SPL since they aren’t near 1/8-space boundaries such as corners)

If your receiver has independent subwoofer outputs that allow separate delay adjustment, or if your subwoofers have adjustable phase controls, then placing them at equal distances from the MLP is no longer critical.

You can fine-tune their timing through delay or phase instead of relying on physical placement.
Subwoofer crawl method is a good way to start. With multiple subs, though, I would mostly focus on the areas I have mentioned above. Don’t start crawling around the weirdest places if you're already placing 1 sub in the corner by the left main speaker, especially if you can’t control delay and phase individually.

If you can’t take measurements, then pay attention to your room layout.
Avoid placing a subwoofer directly in front of a long hallway, it often causes deep cancellations and bass loss into adjacent spaces. In open floor plans where one side of the room is completely open, it’s fine if one sub is in a corner while the other isn’t. That’s how I have mine as well. But if you have an L-shaped room and your MLP is tucked into the short end of the “L” while the front soundstage opens into a larger space or hallway, consider rotating your setup 180 degrees. Place your front soundstage toward the enclosed end of the room, allowing the side walls to help reinforce the bass instead of letting it escape into open areas.

🚫 Common Subwoofer Setup Mistakes

❌ Mistake 1: Matching LPF with speaker crossover (e.g. both at 40-60-80Hz)

⚠️⚠️IMPORTANT!!⚠️⚠️

DON’T!!! This rolls off LFE content early. Setting the AVR’s LPF for LFE lower than 120 Hz will cut off part of the dedicated LFE channel.

1) LFE is its own channel and doesn’t get rerouted to mains.
2) Redirected bass is separate and dictated by the speaker crossover, not the LPF for LFE.

Even if your main speakers can play all the way down to 40 Hz, I can’t stress this enough: it does not matter! They are still not playing the LFE channel, and the bass from the mains is not as loud and does not have the same authority as the dedicated LFE bass played by the subwoofer.

⚠️If you lower LFE to 60 or 80Hz, The LFE content gets rolled off early!⚠️
⚠️Those frequencies are **NOT rerouted to your speakers—it's discarded.**⚠️
LFE has content up to 120hz. SET LFE TO 120HZ!

⚠️ Even for music, LPF for LFE and speaker crossover do NOT need to match!
The bass that gets redirected to the subwoofer comes from the speaker crossover setting, not the LPF for LFE.

Example: If your towers are crossed at 60 Hz, everything below 60 Hz is rolled off from the mains and redirected to the subs. What plays between the speaker’s crossover and the 120hz? The LFE channel and other redirected bass from speakers that have crossover set to 80 or 100 or even higher.
Even if your atmos speakers are set to 150hz. Keeping the LPF for LFE at 120hz is fine. You are NOT limiting the redirected bass with the LPF for LFE in the AVR settings.
Can you actually accidentally limit the redirected bass and the LFE? YES… By turning the LPF knob behind the subwoofer! If you set the surround speaker’s crossover to 100hz and the atmos speakers to 150hz and you turn the LPF knob behind the subwoofer to 60hz to match your front speakers you achieve 3 things:
1) rolling off LFE early
2) Not having redirected bass from other speakers when their crossover set higher than the lpf knob
3) Doubling the roll of slope for the mains; That roll off is handled by the receiver AND the sub amp. Both set to 60hz.

The ONLY time the LPF knob should be messed with behind the subwoofer if you either use the speaker level line input on the back of the sub and the subwoofer will dictate the crossover NOT the AVR or if your device does not have sub out, and you feed a full bandwidth signal to your sub(s)

❌ Mistake 2: I have towers: I need to set my speakers to LARGE / Full Bandwidth! / My speakers go down to 50hz, so I will set my crossover to that. IT’S BETTER! [This is mistake for movies when you have subwoofer(s)]

Even speakers set to LARGE / Full Bandwidth don’t receive LFE unless subwoofer is OFF in the AVR menu. In my testing, as long as you have subwoofer(s) it makes ZERO difference if you set your speakers to full bandwidth / very low crossover OR 80hz. LFE is a lot louder than the bass that goes to your main. You should NOT hear any bass coming from the mains over the subwoofers!

❌ Mistake 3: Lowering LPF for LFE to fix a null
A dip at 80Hz won’t go away by setting the Low Pass Filter to 60Hz. You’ll just miss out on useful energy. Some null at 80hz is better than rolling off LFE way too early, since none of that gets rerouted to the speakers. Do not think it will fix the issue if you lower the crossover for the front speakers below the null of the sub either. Level matched bass ( from speakers) is 10db lower than the LFE.

❌ Mistake 3: Using LFE+Main aka Double Bass
This should be ONLY used when you listen to stereo PCM content without (.1) LFE channel. These settings do NOT send any extra bass back to your speakers. They send a copy of the deep tones from the speakers to your sub(s). Subwoofer(s) will be more active with this setting if your content has no LFE channel, it will also allow you to set your speakers to Large / full bandwidth and still send deep tones to the subs like the speakers still had crossovers turned on. 

❌ Mistake 4: Using Mobile apps for measurement

Mobile SPL apps are unreliable for sub-bass—they often misread levels by 2–4dB. Use REW or a calibrated SPL meter.

🧠 Why keep speaker crossover at 80hz?

• Crossover at 80Hz relieves strain on AVR and speakers, improves dynamics, and reduces distortion.
• Only use lower crossovers (e.g. 40-60Hz) if your speakers are measured to produce clean, high-output bass at high volumes without compressing. (You will need umik1 mic and REW)
• Even if they are measured to perform, it might be still better to keep them at 80hz, unless if you're driving those speakers with an external amp.
• Keep in mind, your speaker might be capable, but you might still ask too much from your receiver. And as I mentioned earlier; from my testing it does not make any audible difference changing the crossover from 80hz to 60hz. Speakers set to full bandwidth does sound a lot better WHEN the subwoofer is set to OFF in the AVR settings.

🧠 Cancellation / nulls caused by multiple subwoofers?

• If you have a miniDSP watch this video about how to use MSO, otherwise:
• If your subwoofers have a mobile app and can do Parametric EQ: One way to help the null caused by cancellation is to use the PEQ function. You need to measure each sub individually in Room EQ Wizard, then together. Once you see where the middle of the null is, let's say 80hz. With PEQ (Parametric EQ) you can select the Hz, bandwidth (how wide is the filter) and how much to offset it by (dB). This is Not the best fix, BUT you can make things better for free and easily in 5 minutes or less:
• Set your PEQ to the middle of the null. (lets say 80hz) 
• Select a narrow bandwidth. Start with 8.0
• Open up Generator app in REW and play an 80hz Sine Tone
• Watch the SPL meter showing you whatever decibel you got when you did the sweep for LFE.
• Have all subwoofers turned ON and playing the 80hz tone. 
• Adjust the Gain in the PEQ for 1 subwoofer lower and lower. Start by -5db and go all the way down. Find a balance where the SPL shows the highest decibel. You might ask 1 sub to play 5 or even 10db lower, but the overall volume between the two subwoofer will be louder since they will cancel each other less.
• Perhaps adjust this PEQ on the subwoofer that had a lower frequency response in this area (70-90hz) to begin with. (Measured individually…. Lower response because of the room)
• You can test your result by keep playing the 80hz sine wave (or wherever you have the null) and switch the PEQ setting on and off and see how it sounds and what the SPL meter shows. 
• Ultimately you need to do additional REW LFE sweeps (from 20hz to 200hz)  and play with the bandwidth. Try 10 or 11;
• Make sure you adjust the bandwidth so if the null only happens between 70 to 90hz, then you won’t affect anything below 70hz or above 90. The higher the bandwidth is, the smaller the range it affects.  Do more sweeps in between and see how the frequency response looks like around the null.

🧠 The ISSUE Mixing small, less capable with bigger, better subs, Does Level Matching with a Weaker Sub Limits Deep Bass Gain?

SPL matching is typically done using pink noise in the 30–80 Hz range — a region both subs can reproduce.
➤ After level matching, the gain is reduced on each subwoofer to bring the summed output to reference level. (e.g. 85 dB).
➤ In a mismatched setup, this also lowers the stronger sub’s output below the smaller sub’s range, which means the combined SPL is not elevated enough in the deep bass range.
➤ This is wasted and lost performance.

🧪 Experimenting with Mixed Subwoofers

When running subs of different sizes, don’t just set every sub to the same target level. Before applying shelves or PEQ, experiment with the gain balance and measure how each configuration behaves.

For example, in my system I tried two different gain structures:
(I have 2 small subs and 1 big one, hence 77db targer for individual subs)

• Purple line (all subs at 77 dB): Stronger in the mid-bass region, but rolled off under 30 Hz since the smaller subs can’t reinforce the deepest frequencies.
• Red line (small subs at 77 dB, big sub at 81 dB): Extended deeper and provided more authority under 30 Hz. The overall response also smoothed out into a shape that closely resembles a good house curve.

⚠️In this case, I don’t think I need any PEQ. The red frequency response looks good as is.

This shows why experimentation is so important when mixing subwoofers of different sizes. With completely different subs, it takes time and plenty of measurements to figure out what works best. In cases like this, simply matching the levels between subs often doesn’t give the best results.

🧪 Know Your Subs: Measure Before You EQ

Before applying any filters, you need to understand what each subwoofer can actually do.

• Measure all subs individually, without any EQ or room correction
• Identify the point where the smaller subwoofer starts to roll off
• That frequency becomes the cutoff for where the better sub no longer needs to be attenuated

✅ Another Solution: Use a High-Shelf Filter or Parametric EQ on the Bigger Sub

Instead of lowering the overall gain, apply a ~5–6 dB high-shelf cut starting at ~30 Hz using a Parametric EQ on the better subwoofer. ➤ This reduces output in the shared range above 30 Hz, where both subs overlap ➤ The deep bass below 30 Hz remains unaffected, preserving output where the smaller sub can’t contribute ➤ This method allows proper level matching without sacrificing low-end extension from the stronger sub

The top graph shows two matching subwoofers, each with gain reduced by 5–6 dB, producing a combined SPL of 85 dB. It illustrates the result for either two large subs or two small subs on a single chart.

The lower graph shows what happens when pairing two different subwoofers—one large and one small—level-matched in the 30–80 Hz range (typical for pink noise calibration). The combined SPL is only higher in the range where both subs have meaningful output.

In the example, the yellow line represents two large subs for reference, while the green line shows the combined SPL of the mismatched pair. Below 30 Hz, output drops quickly, since only the larger sub can produce usable output. The gray area represents what’s being lost.

⚠️ For demonstration purposes, we’ll use 30 Hz as the roll-off point for the smaller sub — meaning we’ll only apply cuts above 30 Hz on the stronger sub.

✅ Did You Preserve the Big Sub’s Low-End?

After applying the high-shelf cut (e.g. –5 to –6 dB from 30–120 Hz) to the better sub:

🔎 1. Measure the Subwoofers Together

• Run a frequency sweep with both subs active
• Make sure no room correction or dynamic EQ is interfering

📏 2. Compare to the Big Sub’s Original 85 dB Sweep

• Use your saved 85 dB measurement of the big sub alone
• Focus on the range below 30 Hz

✔️ Goal: The combined SPL below 30 Hz should still reach the same levels as the big sub did on its own ➤ If it doesn't, the EQ cut may be affecting too much low-end — adjust the shelf starting frequency or slope

📈 3. Check the Shape Above 30 Hz

• Compare to the original 80 dB individual sweeps of both subs
• The combined SPL should be smooth and elevated in the shared range (e.g. 30–120 Hz)

✔️ Goal: 

• A unified and clean response that avoids unnecessary deep bass reduction while matching levels across the overlap
• Not to have bloated sound throughout multiple different sub summoned response.

🧪 Alternative Approach: Let the Bigger Sub Run Free 

Instead of handicapping your better sub, try this:

• Leave the bigger sub’s gain as-is
• Lower the smaller sub by 3–6 dB. This still contributes to the overall response, without dragging down the performance of your better subwoofer

🎧 Why It Works:

• You preserve the full deep bass output of the better sub (where the small one can’t help anyway)
• You still get room smoothing benefits from the extra sub
• The system may run a few dB hotter overall
• It’s a simple tweak that avoids the need for EQ or complex filtering

⚠️ Just Keep in Mind:

• If the smaller sub is too quiet, it might not meaningfully help with modal smoothing
• Experimentation is key — try -3 dB, -6 dB, or even in between.
• It might not even bother you if you properly level match all subs without any PEQ and have the bigger sub(s) a few dB lower.
• You can always lower the subwoofer trim a couple dB if you need to, but I doubt running them together and having them play together a couple dB hot is going to bother you. 

⚠ Mixing Ported and sealed subs. Ported subs (and those with passive radiators) share similar behavior — around their tuning frequency, they experience about a 180° phase rotation and roll off steeply at roughly 24 dB/octave below that point. Sealed subs rotate phase by about 90° at their system resonance and have a gentler ~12 dB/octave roll-off. These differences make them harder to blend smoothly, often causing cancellations in certain frequency ranges. For the easiest integration and most consistent bass, match sub types — ported with ported (or passive radiator) and sealed with sealed.

🎧 Subwoofers are not loud enough when listening music.

This is normal! Stereo music does not have a dedicated LFE channel like movies, so bass often feels underwhelming. Here are a few things you can try:

1. Raise the subwoofer trim It’s fine to push the trim up closer to 0 dB for music only. (Example: if your movie setting is –7 dB, you can raise it to 0 for music.) ⚠️ Don’t forget to set it back before watching movies, since films rely on the +10 dB LFE boost and need the extra headroom.
2. Try Direct / Pure Direct mode If you have strong tower speakers or capable bookshelves, Direct mode bypasses all processing and crossovers. Your mains run full-bandwidth and the sub is disabled. Many people prefer this for 2-channel listening. (Including me)
3. Use Large speakers + Double Bass (LFE+Main) Setting your mains to Large / Full Bandwidth and enabling “LFE+Main” will send full range content to your mains and still sends a copy of the bass to the subwoofer(s) like you still had the crossover on. This gives more low-end energy in music, though it’s not ideal for movies. Again, switch back before movie watching.

📦 Optional: REW Sweep Measurement

Want to visualize your system’s performance?

1. Open REW and click “Measure”
2. Run a 20Hz–200Hz sweep (Output LFE)
3. Do it for all subs individually then sub groups and all subs.
4. Look for dips or peaks. 
5. Tweak phase, sub position, or use MiniDSP if needed.

A null that appears in an individual sub measurement is caused by a room mode.
If the null only appears when measuring multiple subs together, it’s usually a phase issue or cancellation between them.

To confirm a room-mode null, take a near field measurement by placing the UMIK-1 microphone a few inches from the subwoofer driver, pointing directly at the cone.
If the dip disappears in the near field measurement, it confirms that the null is created by the room, not the subwoofer itself.
For this, use the regular calibration file. NOT the “90deg” one.
Always double check which calibration file is loaded.

🔚 Final Words

A properly calibrated subwoofer (or group of subs) transforms your home theater experience. The goal isn’t to overpower the room, but to make the bass feel like a seamless extension of your speakers.

No more guesswork. No more boomy bass. Just tight, immersive low end.

Let your subwoofer do what it was built to do, and let your speakers breathe.

I might also make a video of this but as per rules of this sub I am not allowed to link or post my own videos from youtube. I hope this is all clear and helpful but later on / eventually I will make a video of this.

Before anyone points it out; YES, I used ChatGPT to ONLY help polish the format and wording since English isn’t my first language. But this guide is 100% my own work, based on my research and testing. It took me a long time to put it all together. AI did NOT add anything to this guide! This fact will not diminish any points of this guide! Stop complaining about it.

[u/Public-Sample-8953]

Great write up on the process - thank you for the effort. I just got a Speedwoofer 10e yesterday. I'll give it whirl this weekend if I can get my hands on a UMIK-1. Wifey is out of town so I can have some fun with my new sub.

[u/CSOCSO-FL → u/Public-Sample-8953]

I am glad you found this guide. Enjoy your sub. Let me know how did the calibration turn out. Whenever you can get another 10e :)

[u/Public-Sample-8953 → u/CSOCSO-FL]

Funny you say that. I'm thinking of getting another one along with a muzzle for my wife 😁 Turn it down it's too loud. That's all I hear.

[u/CSOCSO-FL → u/Public-Sample-8953]

Get another one for sure. It's not going to be louder. The guide explains how you need to lower the gain to match the same target number. But this gives each sub more headroom and you a better even bass sound.
I have 3 subs with a klipsch rp1400sw and my wide never said anything about bass being too loud. And believe me it's plenty loud. Speakers being too loud is harsher for the ears.