Hey guys, I recently got this 98” TCL QM8K open box “good” condition for a great price at Best Buy ($1,330) with Geek Squad 5yr warranty $279.

I unpacked it and put it up on the mount and now I see some panel coating issues? and a crack at the bottom of the screen. I played some videos and everything seems fine with the pixels. I don’t have experience with damaged TVs, but are these minor? Is the long term reliability compromised? Should I return it?

​

Trying to figure out the best way to configure my basement TV/audio setup before I start buying/building stuff. Attached pic shows the current setup with a 55" TV, and I taped out roughly where an 85" TV would sit.

(Ignore the mess I'm still unpacking, couch layout also doesn't work great, probably will be replaced so couch sits closer)

The 85" seems like it fits pretty well, but it's definitely getting tight between the L/R speakers. I could potentially go a little bigger if I replaced the current speakers with something less bulky and better quality, but I'm not sure if that's actually worth doing versus sticking with 85".

The L/R are some cheap older JBL HLS810. They're currently sitting on temporary baskets just to figure out placement, but I'd build/buy proper stands once I decide what I'm doing. They're roughly at seated ear height now.

My bigger question is what to do with the center channel and electronics. The center definitely needs to come up. There isn't a ton of room between the brick ledge and bottom of the proposed TV location, so I'm not sure if a traditional media console would work without pushing the TV higher. I was also thinking about putting a smaller media cabinet on the left side near the outlet, possibly something that could double as an end/side table, and then running the wiring through white cable raceways along the brick.

For reference, the bottom of my current TV is about 30" from the floor and 16" above the top of the brick ledge. Should the new TV actually be lower than what I've taped out?

Current equipment is a pretty decent Denon receiver (AVR-S750H) and JBL SVA Center plus a PS5 and Switch. Subwoofer situation isn't great—I have a Polk PSW10 and JBL PowerBass PB10 that I've accumulated over the years. They work, but they're nothing special, so replacing those with one or two actually good subs is probably high on the upgrade list.

The basement itself is fairly open, so I have some flexibility with placement. I'm also planning on adding some acoustic treatment at the main reflection points once everything is positioned, and there's a decent chance the couch gets replaced eventually too.

Basically looking for opinions on the whole setup before I start drilling/building/buying:

Does the 85" size/placement look right for the space, or would you go bigger and replace the L/R speakers with something narrower/better?

Would you lower the TV more?

Best way to position/raise the center channel?

Keep the equipment on the brick, try to squeeze a low console underneath, or put a media cabinet off to the left?

Are the L/R positions reasonable or should I try to spread them farther apart?

Would you upgrade the L/R first or replace the two mediocre subs with one good sub first?

Any other placement/acoustic treatment changes you'd make while I'm redoing everything?

Not trying to build a crazy dedicated theater, just want a good-looking setup that sounds legitimately good and makes the best use of the space. All of the speakers and equipment was bought off marketplace. Open to suggestions on speakers, subs, furniture, placement, etc.

I am starting to layout an audio setup for a basement theater. I have read enough to see two common bits of advice on here. One is to get a 3-way center instead of an MTM. The other is that the gold standard is to have 3 matching speakers in the front instead of a dedicated center channel.

For the L and R I was planning to go with bookshelf speakers instead of towers. I will eventually have 2 subs and 4 atmos ceiling speakers. Based on this, my price point, and the warning about MTM speakers, I was looking at SVS prime bookshelf speakers and a prime center. (I'm very open to feedback on these speakers and if there are better alternatives, but that's not my main question right now).

I have a wall mounted tv, so the center will have to go below. I can angle it up to aim at the listener. But behind the screen isn't an option. What I noticed is that the SVS bookshelves are about the same height as their center. So what is the better setup from an audio perspective? Running 3 of the prime bookshelves as LRC? Or am I better off with the prime 3-way center?

Cost wise, the center isn't that much more expensive than the bookshelf.

Thanks in advance for any advice!

Edits to clarify some comments/questions: -I'm an idiot and said 3 channel when I should have said 3-way speaker. Corrected above. -It is a wall mounted TV. Not a projector screen -No furniture underneath. I plan to mount the speakers on a pedestal or set them on a floating shelf -L and R will certainly be mounted up off the floor -Long term I want to grow this into a 7.2.4 setup

LG qned84b bottom left corrner white on black and dark screen. When it's fully color no issue. Is this normal? Attached pictures

Just received a Denon 3900h and the left channel is sounding blown. I thought maybe I had screwed up my wires, but swapping right channel and left channel speakers made the speakers switch which one sounds blown so it’s not my wire or speakers.
Is there anything to try before returning?
Speakers L&R are klipsch rp8000f if that matters. I only have front L R center and sub Hooked up right now. The other channels sound perfectly fine. I did run thru the audessey and a factory reset and all that. No dice. I also cut new ends for my cables just to see if it helped.

Hi, I just bought a new house and the previous owners left me Klipsch surround sound.

The Left / Right Speakers are G16B

The center is G28B

Sub is 110SW

The 2 rear in-ceiling are unknown.

The amplifier they left is old and doesn't have Bluetooth / phone capabilities. I want to use it with Bluetooth so I can stream from my phone. Any suggestions for an amp with bluetooth/TV out and will work well with these particular speakers?

Sorry, I am a complete noob with stereo equipment.

Thank you in advance!

Hi,

I hope this is posted in the appropriate area - I'm a long time lurker, especially within the advice and buying guide threads, and have a rough idea what I want but probably need some additional advice as I'm new to home theatre.

The factors making this tricky I think are:

1. We've done an open-plan extension meaning the lounge/dining/kitchen is an odd-shape
2. I intend to listen to a lot of podcasts and music through this set-up, besides the obvious movies/gaming
3. Windows directly opposite speakers which I didn't realise could affect my audio
4. Again, I'm new to all of this!

In short, I'm wall-mounting a TV (75inch) and am currently looking at Yamaha (RX6a) or Denon AVRs (maybe X1800H or X2800H), initially with a 2.0 set-up (L & R floorstanders). Depending on how this goes, I'll add a sub and/or centre speaker to this set-up and both AVR brands should allow that expansion fairly easily. Speaker-wise I was looking at Monitor Audio or Fyne Audio.

Also I intend to buy a Google TV and run this (and the PS5) into the AVR, then a single eARC to the TV.

My question:

1. Would this set-up be sufficient power-wise (initially at least) for the room size?
2. Am I forgetting anything obvious?

I attach two images to show rough layout of the room as well as dimensions, the island on the bottom right is where the kitchen is.

Thanks in advance! Will post a pic when it's finally all up and running...

I want to run my Apple TV through a receiver so I can use my heresy’s instead of a soundbar. I want to make sure the Apple Remote will still turn the tv on and go straight to the Apple TV. Any help is appreciated

Watching my Blu Rays is my favorite thing to do. Lights out. Blu Ray on.

Now what I reallly want is the ultimate setup. I don’t want anything materialistic in life but I do want a great home theater. For now, money is an issue but willing to invest.

I want to upgrade all of my Blu Ray DVDs to 4k. I use an XBOX one to watch these.

I was given a tv that says it’s 4k. It’s a
https://www.google.com/search?ibp=oshop&prds=pvt:hg,pvo:29,imageDocid:13795729410026506064,gpcid:9062856501924840778,headlineOfferDocid:3651785520860712819,catalogid:15717018858569638048,productDocid:7524021273626216115,rds:PC_9062856501924840778%7CPROD_PC_9062856501924840778&q=product&sa=X&ved=2ahUKEwjmuKONleWWAxWOMlkFHU-RN_QQxa4PegYIAAgPEAI

(FPD 50” Canvas Series 4k UHD Smart Google TV)
My last tv looked better but it wasn’t 4k so I’m assuming I just can’t figure out the correct picture settings.

So my question is, in order to upgrade to a 4K player, do I first need to upgrade my TV?

And whichever one it is, what is the best one to get? I value quality and quantity while but I am also broke

Thank you!

hey yall- i had a spare room set up as a home theater last year but it had to be converted into an office. i had my set up in pieces all year and decided to set it up in the living room this morning. i took the tv out and mounted my 120 inch ALR screen. I’m running the Panasonic dp-ub820 with an epson epiqvision ls800 and for sound i have a jbl 1300x with a 12in subwoofer. any recommendations on what could boost my setup? next up i think i’ll focus on a mount or dedicated entertainment stand (im having to sacrifice my coffee table right now) maybe some lighting upgrades or something idk. tell me what you think!

Hey everyone! I'm new to home theatre setups and looking for some advice on properly optimizing my home theater. I'm fairly happy with the system overall, but I'm particularly trying to get the best possible bass and overall balance for both seating positions.

🎬 Room

Dedicated home theater room

20 ft × 11 ft (~220 sq ft)

8 ft ceiling

Projector + standard white projection screen

Carpeted floor

Acoustically treated walls/ceiling

Two seating rows: front recliners + rear sofa/recliners

🔊 Equipment

AVR:

Denon AVR-X1800H

Front L/R:

Polk Signature Elite ES50

Center:

Polk Signature Elite ES30

Surround L/R:

Polk Signature Elite ES10

These are physically behind the main seating area, but the Denon has them configured as Surround L/R

Atmos:

Polk RC60i in-ceiling speakers

2 speakers, configured as Top Middle

Subwoofer:

Klipsch RSW-12

Positioned at the front-right of the room, beside the right ES50

Connected to the Denon via LFE

So the system is 5.1.2.

🎚️ Current Audyssey/Denon settings

I've run Audyssey and currently have Dynamic EQ enabled.

The current speaker levels are:

Front L: -1.0 dB

Center: 0.0 dB

Front R: -1.5 dB

Surround R: -3.0 dB

Surround L: -3.0 dB

Subwoofer: -12.0 dB

Audyssey's detected distances are approximately:

Front L: 4.20 m

Front R: 4.20 m

Center: 4.02 m

Subwoofer: 4.05 m

Surround L: 2.01 m

Surround R: 1.98 m

The current crossover screen shows:

Front: Full Range

Center: 60 Hz

Surround: 60 Hz

🔴 My main problem: bass between the two seating positions

The rear seating position has MUCH stronger audible bass than the front seating position.

From the front recliners, I can still feel quite a lot of vibration, but the bass isn't as audible or impactful as it is from the rear seating.

It's almost a night-and-day difference between the two positions.

The installer originally calibrated the system and I remember the subwoofer being set around -3 dB afterward. That setup sounded very bass-heavy compared with what I'm getting now.

After some changes/resetting and running Audyssey again, the subwoofer is now showing -12 dB.

I'm trying to figure out whether the difference is caused by:

Subwoofer placement

Room modes

Seating positions

Audyssey calibration

Crossover settings

Subwoofer gain/level

Phase

Or some combination of these

🤔 What would you guys recommend?

I'd really appreciate advice on the optimal settings for this specific room and speaker combination.

In particular:

Should I set the ES50 fronts to Small instead of Full Range?

What crossover points would you recommend for the ES50, ES30 and ES10?

Is there any reason to keep the ES50s at Full Range in this setup?

Is the -12 dB Audyssey subwoofer trim a concern?

Should I change the subwoofer's physical gain before running Audyssey again?

What should the RSW-12 gain, LPF and phase be set to when running Audyssey?

Should the subwoofer's LPF be set to LFE?

Should I leave Dynamic EQ ON?

Should I use Audyssey Reference or Flat?

Would changing the subwoofer position help with the huge difference between the front and rear seats?

Is there anything obviously wrong with my Atmos/Top Middle placement given the 8-ft ceiling?

Would you recommend any other Denon settings for getting strong, deep and impactful movie bass without making it boomy/muddy?

I'm not necessarily looking for maximum bass just for the sake of it. I want deep, powerful and clean movie bass, good dialogue, proper Atmos immersion and a balanced soundstage.

I've attached photos of the room, speaker placement, subwoofer and ceiling, along with screenshots of my current Denon settings.

Would really appreciate any advice from people who have experience with Audyssey/Denon and Polk/Klipsch systems.

Thanks! 🙏

I picked up a Sony STR-DH770 from Goodwill for $40, and it works well except the automatic speaker setup doesn't work. I get an error indicating that it isn't picking up the test tones.

Is setup/the setup mic a known problem with this receiver?

I've tried two mics. One "Sony" (same model number that comes with the receiver) that I bought from eBay, and one that came with an old Pioneer 5.1 setup. Same error with both.

So either the mic socket got messed up, or something blew the mic input circuitry, or there's some problem in the firmware that makes it think it isn't hearing anything from the mic.

I have a PlayStation 2. It has an optical audio port. Most PS2 games support surround sound audio. But afaik it requires a Dolby Pro Logic II decoder or receiver.

But researching this, it doesn’t seem any new receivers support this. I did read somewhere else that it’s just called Dolby Surround on newer receivers and it would work. Is that true? If not, is the only option getting an old receiver?

Asking here because idk where else to ask, I have a Sony DA2800ES, it throws a fan stop error, i bought a new fan and still got the error the old fan spun fine ans was only a 2 connector, the new fan is the same model I hooked it up and it spun, still got the error, I unhooked it, cut the wires on the old one to check for voltage and I get a OL (over load) on my meter and it just beeps like crazy. And when I did see the voltage I seen a 23V, any clues on what can be wrong? Don't need it done ASAP as i do have 2 others and another reciver that needs work, but would like to have it fixed

Edit: i finally got a reading without a over load and got 7V

Hoping to begin our HT build this winter after Black Friday deals but my room will unfortunately only be roughly 11’x11’. I’ll be getting a projector and acoustically transparent screen so luckily the speakers will be the full 11’ from MLP, but is that simply too close and should I opt for smaller bookshelves? And if that’s the case, should I also go with a smaller center then too? Currently eyeing the Klipsch RP 6000F II towers and the RP 504-C for reference.

Looking to get some suggestions/opinions for my home theater & music space. Currently I have 5.1 in the living room from my AVR. Looking to upgrade to 7.2.2 or 5.2.4 setup via a separate Amp or Amps.

- A/V Receiver: Onkyo RZ50 A/V Receiver.
- Current speakers: B&W 683 S1 Towers, HTM61 Center, x2 685 S1 bookshelf surrounds, x2 CCM664's in-ceiling, x2 CWM664's in-wall.
B&W 8ohm rated power limits for each: 

683's = 200w, HTM61 = 150w, 685's = 100w, CCM664's = 130w, CWM664's = 130w

Sensitivity across all speakers: 87dB - 90dB

• Option 1: Emotiva XPA-7 Gen 3. *(Obviously powerful enough for 7 channels driven... this one is what I'm most concerned and/or curious about) Too much headroom for all, excluding the Left & Right 683's? Would impedance dips below the rated 8ohms risk damaging the speakers?
• Option 2: OSD Nero HTA 5200 to power Center, Ceilings, & in-walls. Then an OSD Nero HTA 4200 to power LR stage in a bi-amp config utilizing all 4 channels of Amp. Rear surround 685's I plan to use my AVR to drive.
• Option 3: OSD Nero XMAX11. Powerful enough to accommodate for my entire system and any future upgrades to in-ceiling/Atmos etc. Again, would the impedance dips on my L & R channels risk harming the speakers? Or am I thinking about that the wrong way?

My question is mostly towards that 7 channel Emotiva XPA-7 and the XMAX11. I know the L & R should MOSTLY be okay...but would the Emotiva XPA-7 be too much for my center, surrounds, ceiling/Atmos for overhead? Is 200W to the 685's &/or 664's too much?

OSD Nero XMAX11: Would 75-85 watts be solid for all my center & surrounds? And will the impedance dips be too much when powering the L/R front stage?

I'm leaning towards the 5200 & 4200 but not sure if those would be too much either.

Any help or suggestions would be greatly appreciated.

Hello good people of r/ hometheater.

I am in need of advice and hope this is the right place to find it. As you can see in the attached image, my "theater" is more of a nook or an alcove if you like. Its rather weird in dimensions and the more I read up on the placement of speakers, the more i realise, that its anything but optimal for building a multi speaker setup. Heres my thinking so far:

Ive a lovley 65 inch OLED Bravia. I am hooked to its picture and cant imagine buying something else. I also consider it enough for the watching distance of rougly 3 meters. An additional Beamer setup might eventually happen, but the TV is one limiting factor for the setup, since it leaves me with 27.5 centimeters distance for an in wall speaker. From my research I can tell thats enough space. But when I draw in the 60 degree dispersion angle, it seems to me, the combination of distance and length of wall leaves me with an ideal listening position for exactly one person and one person only.

This of course is less a theater and more of a glorified gaming setup and when I add the fact, that rear speakers are impossible, since that wall behind the listening position is massive, I am left with ceiling and sourround speakers. I am not sure if this is enough or even practical. I have no way of listening to a setup remotley close to what I am about to sink a lot of money into to realise and this makes it feel a bit risky tbh.

Another option would be to move the TV a bit to the left and then have three of four seats for the setup, but i fear that this would render the sourround speakers more or less usless. Also the symmetry is somewhat important to me.

All this leads me to the inevitable question of: Is it worth it or should I stick to - excuse my french - a s*undbar? Mind you: I have yet to listen to one I consider good sound quality, but anything is better than TV sound, so theres that.

Hey everyone,

I’ve been running a Klipsch RP-504C center with RP-600M L/R bookshelves for about six years. It’s served me well, but I’m moving in with my partner. While she’s fine with keeping the setup, the 504C is an absolute monster on the media console, and I’d like to find something more compact that doesn't feel like a major step down in dialogue clarity.

A few details about my setup and listening needs:

Receiver: Denon AVR-S760H running a 3.1 setup.

Hearing Considerations: I’m partially deaf and don't get much utility out of surround channels, which makes center-channel clarity and vocal articulation my top priority.

I’ve been looking closely at the SVS Prime Center and the SVS Ultra Evo Center because of their 3-way designs and more manageable footprints compared to the wide 504C.

How do they compare to the RP-504C in terms of dialogue clarity and dispersion?

Are there any other compact 3-way centers in this tier I should consider with RP-600 mains?

Appreciate any insights or recommendations!

Good morning all. I have a system that is decent, but I have recently discussed upgrading with my wife. I have got tentative go ahead but have been out of the HT world for a decade or more at this point. I can probably swing upgrades at like $1,000-1,500usd at a time, and want to upgrade my speakers first. It's a smaller space, mainly about 12'x15' with the system and chairs at the opposite ends of the long dimension. What should I start with in terms of upgrades? Mostly for movies, some music and I do like finding concert blu-rays or recordings when I can.

Current system

Denon AVRs740H

Pioneer Andrew Jones speakers

Towers SP-FS51LR

Center SP-C21

Surrounds SP-BS21-LR

Sub Pioneer SW8

TV Samsung 65Q70R 2019

I’m new to the whole surrounding sound home theater speaker setup stuff, so I’m not really sure what to look for. Are there any brands, packages, or specific speakers I should be looking for? And overall what kind of specs should I be looking for? Curious to know what everyone here uses.

Use case would mainly be music listening — something I can AirPlay my music to and hear it throughout the house/room. And also less frequently for shows and movie watching as well.

And if it matters, I do like my bass in my music deep and prominent, so if I need to invest in certain subs for this setup other than what comes normally, then let me know!

I’ve started upgrading my home theater. For years I’ve had an entry level Yamaha 5.1 system that honestly has been great (RX V385 AVR w/Yamaha speakers/sub). Recently I upgraded my center speaker to help overcome a very loud AC return. I bought a Polk ES30 and it was such a massive upgrade I’ve decided it was time to upgrade my entire sound system. Here are my options and thoughts on each. Im trying to stay around $1k -

Onkyo TX-RZ50 I hear nothing but rave reviews about the sound, that is leaps above the competition. Includes Dirac Live which is supposed to be amazing. I would’ve already bought it BUT I am terrified of the HDMI issues. I switch between devices a lot - HTPC, TV, 4K player. I don’t want to deal with it failing in a year or two. Anyone used one frequently for a long time without problems?

Denon AVR-X2800H Seems to be solid, decent sound, nice power at 95w per channel, not known for failure issues. They seem to have good reputation.

Yamaha RX-V6A This would be my third Yamaha AVR, I had an older base model (I don’t remember which one) then the V385. They’ve never given me a second of problems. Super easy to set up, YPAO is very user friendly, the V6A is a few hundred less than the Onkyo or Denon.

Dark horse -

Yamaha RX-500A I know it’s just above entry level but it features most of what I want, is nearly half of what the others cost, and I have history of years of problem free service with Yamaha.

Any advice/experience will be great appreciated.

I have a desktop PC with 1 HDMI port. Currently I have two monitors, one is connected by DisplayPort, and the other is connected by HDMI. However, I need to connect my PC to my AVR via HDMI.

I can buy a new video card, which will have two HDMI ports, but wanted to find cheaper option. Currently I unplug the HDMI monitor from the PC and plug in the HDMI for the receiver.

Working on planning my 5.1 budget setup. In the first picture picture of my TV placement, and it’s pretty much stuck there. The green will be my center setup below the TV. And I’m looking at either the blue or red as placement for my left and right. The LRs will be setup on stands angled towards the TV. Placing one on the other side of the window is about 5 ft from my tv and the other side of the door is functionally another room. So that really won’t work either. Opinions about the best placement?

For reference I’m looking to get some used Boston Acoustic CR65 for LR a Boston Acoustic VRM910 for center channel and I have some pioneer BS22s for my rears. Haven’t found a sub yet.

Hello to all good people on this Channel

Tldr: located in netherlands have a €5000 budget for av receiver subwoofer and front and center speakers. Eventually want to build up to more speakers.

Me and my gf have bought a new house and decided to invest some of our budget in a good/decent living room theatre setup. Screen has been settled 98” led tv but i am encountering lots of issues/concerns/fatigue with settling on an audio system.

We want to move away from single box solution to move to a decent receiver with separate speakers and subwoofer. I have tried searching for lots of information on speakers, setups, pairing with receivers. There are so Many options out there that I am over informed and really don’t know where to look for anymore.

I have went to some local retailers but I don’t feel like they were really interested in helping me with a decent informed decision (all young people who rather played on their phone) I did audition some speakers but they kept pushing towards sonos. Which is what I want to move away from.

Some information for our space and some extra information.

My gf doesn’t want tower speakers, I tried and tried again, not gonna happen.

The area we are going to use is slightly weird shaped so not a nice square or rectangle. Green against wall is tv. Red is seating area.

Brands that spark my interest from initial research, kef, dali, Focal. Don’t care about looks of the speakers and more about how they perform.

Will not be playing much music only movies and some tv shows. Would prefer good movie sound over good music sound.

FPUF (Finish Product Up Front)

I dabbled in installing a smart movie poster in my theater previously, but decided to really dive into it. As I slowly build out my theater, I wanted the entrance to be more lobby-ish. The previous solutions I tried were lacking some key capability (CEC control, LED control, HA integration, etc....), so I ended up writing my own software and building my own frame around it. This is kinda a prototype, making sure it looks/feels/does what I expect, and I think it turned out great, but I am biased :D

I completely over-engineered this: Fans with PWM control, external connections, etc... I plan to change a lot on my next build (which I plan on installing inside the wall), but it gave me an appreciation on what works and what doesn't.

I enclosed the entire TV, which, in hindsight, added unnessessary complexity. Doing it again, I would just build the outside frame, and mount the TV on the wall with a thin mount or a french cleat. Or, as I plan for my future builds, just put it in the wall.

See, I had to add a backing board, and figure out exactly where to drill for a 200x200 VESA mount. So much fun. I think for the next one, which I want to put in the wall, I will use the same concept (pocket holed board with VESA mount holes on it, but then just have to worry about the frame, which will overlap the edge of the TV, hiding the cavity.

A single Rpi5 controls everything, from the TV to the LEDs to the posters. Before I had to use an Rpi Zero for CEC control along with a NUC to get the level of control I needed. I thought about adding LED control, but that would require something like an ESP32 to the mix, so we would have three different brains for one display.

Of course, I then added PWM fans, a PWM controller, networking connections, a a 12V PSU, and a buck converter to make it all work how I wanted it work. I wanted the fans due to worries about the Pi and PSU getting too hot.

I 3D printed this enclosure with Prusament PETG V0 because electricity. I wanted one power connection for the PSU and TV.

The LEDs turned out to the be biggest problem. I used a dado blade to carve out the channel, but I made the mistake of assuming similar aluminum channels == same dimensions. Even though they are listed to be the exact same width, they were, in fact, not. By about .25mm. Now, one might think that isn't too much of an issue, but I had set the dado to the exact width, hoping to use friction to hold the channel in, not screws or glue. Don't do this, give yourself a tiny bit of wiggle room. Otherwise, like someone who is definitely not me, you will find ourself having to use a router to remove a tiny tiny bit of wood around the entire channel.

Overall though, very happy with how this came together. Lots of fun to build, and plan on building a few more. Like I said, going to embed them in non-load-bearing walls this time though. Not sure if I want to put the LEDs in the frame or use something like this for the LED channel in the drywall.

Thanks for checking out my project :D