Help me plan out my garage stereo

[95maxrider]

Hello everyone! This is my first post on the forum. I've lurked for quite some time, but I finally need to ask some questions.

My name is Nick, I'm 40 and have been into stereos since I was a kid, but have never had much of a budget for anything very nice, mostly just 2.1 setups with whatever I could get my hands on. My very first job was at a high end stereo store back in 1999 where they sold fancy stuff like those Martin Logan speakers. Most of my stereo money has gone into my cars rather than my home.

I'm in the planning phase of building my attainable dream garage, and I want to have my stereo plans complete before we start building, so I know how/where to run the wires. Here are the basics:

-900 sq ft garage (25' wide by ~35' deep)
-14' ceilings
-I would like to run two sets of bookshelf speakers in stereo (A+B) mode, plus a sealed powered subwoofer. I just don't think one set of bookshelf speakers can give proper coverage in a space this large where I'll be moving all over the place, and I don't want towers taking up floor space.
-I don't stream my music, it's all located either on my computer or Fiio music player. It's a mix of FLAC/WAV/MP3.
-I don't need a 5.1 or fancier receiver since I don't need surround to listen to music
-I'd like to keep the budget to around $2,500, and I'm okay with buying used parts if it's from a reputable brand
-Right now my music source in the garage is my Fiio X3 with a 128 GB SD card, playing into a 20 year old Sony boom-box style stereo. In the new garage the source will likely be a laptop or desktop that I build with unlimited storage space.

Here are my current candidates:

Bookshelf speakers:
Two sets of Hivi Swan 3.1A DIY Speaker kit with stage 4 Sehlin mod (4 ohm) ~$350 each pair. I have already purchased one set, but haven't started assembling.

Based on their performance/value here:

Hivi 3.1A DIY Speaker With Sehlin Mod Review

This is a review and detailed measurements of the Swan Hivi 3.1A DIY Speaker kit with modified crossover by Sehlin Sound Solutions. It was kindly sent to me by @Mudjock as tested. The kit by itself goes for US $300 including Prime shipping. Unusual for a speaker kit, it comes with everything...

www.audiosciencereview.com

and here:

Speaker Data - Preference Ratings & Graphs

Speaker Preference Ratings & Graphs

sites.google.com

https://www.amazon.com/HiVi-Swans-Passive-Bookshelf-Speakers-Pair/dp/B09XGYJFRQ?crid=DGXFIYVOX6J0&dib=eyJ2IjoiMSJ9.tyIm5CVmDY0KvAP1w8Sexg6eOxxhvE1IN1hWAOpT5OL1NWjYX5EBSjtDWc85wOuhRuUKa5XZGoP1R3e9mePtq5fIcrB_gsmhDC38K-9xXbV2pj-Mjukx9xaLiUpqGcxqEvE7mA8RlvzPDobq6YEgFVzyP8q7uuv11dD2EaZOR-BFPJ-nSju2SIoka4kfdgsVjw7VborFF0EMA6G-pz71Z8HCyRIXIDlbIR8YU0C_AZc.3i0idPJBLTA2umeTeBWZ2DlPkxZN5yVuysFQiLSxA8Q&dib_tag=se&keywords=3%2Bway%2Bbookshelf%2Bspeakers&qid=1721849586&sprefix=3%2Bway%2Bbookshelf%2Caps%2C92&sr=8-4&ufe=app_do%3Aamzn1.fos.1740e8b9-be2d-46a4-a376-9d8efb903409&th=1

Subwoofer:
HSU Research ULS-15 MK 2, ~$900

Based on its performance/value in this chart:

Subwoofer Comparison (by @sweetchaos)

docs.google.com

ULS-15 MK2 Subwoofer

Introducing the ULS-15 MK2, the renowned musician's companion subwoofer that has garnered immense popularity in music recording studios and various other contexts. Well-known for being a musician’s companion subwoofer Most popular subwoofer for music and cinematic recording studios Smallest...

hsuresearch.com

Receiver:
This is where I think I need the most help!

The Fosi Audio V3 Mono class D amplifier seems pretty appealing for ~$150, but it's not clear to me how/if it/they can be used to power 4 4-ohm speakers from a single source.

Fosi Audio V3 Mono Amplifier Review

This is a review and detailed measurements of the Fosi Audio V3 Mono class D amplifier. It was sent to me by the company. The price with the power supply I tested is US $139.99. I must say the concept of a "monoblock" amplifier in such a small size runs foul of any expectation a longtime...

www.audiosciencereview.com

I've found good used deals on the Yamaha A-S701/801

Yamaha A-S701 Stereo Amplifier Review

This is a review and detailed measurements of the Yamaha A-S701 stereo integrated amplifier with included DAC and Phono stage. It is on kind loan from a member and costs US $800. The A-S701 is one of the best looking amplifiers I have tested. Yes the controls are plastic unlike the glory days...

www.audiosciencereview.com

But then I learned it can only run 2 pairs of 8 ohm speakers, and not these 4 ohm speakers.

https://www.crutchfield.com/p_022AS801B/Yamaha-A-S801-Black.html

Given my remaining budget for the amp (~$700), the power needs of those four 4-ohm Hivi Swan speakers, and my digital source, what should I be looking for? I'm looking for any and all feedback you can provide on this project! If you think I need to start from scratch and rethink the whole thing, please say so.

Thanks!
Nick

 

[Count Arthur]

Given that you'll be moving about, I would consider having all 4 speakers outputting a mono signal. Unless you're in fairly fixed position between a pair of speakers, stereo doesn't make a lot of sense.

 

[RayDunzl]

Given my remaining budget for the amp (~$700), the power needs of those four 4-ohm Hivi Swan speakers, and my digital source, what should I be looking for?

Have you considered buying two cheap stereo amps splitting the signal from the source?

Four if they are the Fosi mentioned.

 

[95maxrider]

Given that you'll be moving about, I would consider having all 4 speakers outputting a mono signal. Unless you're in fairly fixed position between a pair of speakers, stereo doesn't make a lot of sense.

I've never set up a stereo to function like that, but I understand why it would work in this situation. But how would I wire it up to do that? Can a normal stereo receiver work in that way, or is that more of a reason to go with something like the Fosi mono amp?

 

[95maxrider]

Have you considered buying two cheap amps splitting the signal from the source?

I have not, but that's mostly because I wasn't sure if something like that is a good idea. Is signal degradation not an issue when you split it like that?

 

[RayDunzl]

Is signal degradation not an issue when you split it like that?

You're gonna be listening in your garage, so I'll say "yes, it is not".

 

[RayDunzl]

Another alternative could be to run two 4 ohm speakers off one 8 ohm amp channel by wiring the speakers in series instead of in parallel.

 

[95maxrider]

Crap, I didn't realize I was speaking with the Central Scrutinizer, I'll try to keep my plooking under control and to unload in the white zone!

 

[95maxrider]

You're gonna be listening in your garage, so I'll say "yes, it is not".

Lol, fair enough.

Another alternative could be to run two 4 ohm speakers off one 8 ohm amp channel by wiring the speakers in series instead of in parallel.

It's been a while since I brushed up on ohm's law, but would this cut power output in half for each speaker?

 

[RayDunzl]

It's been a while since I brushed up on ohm's law, but would this cut power output in half for each speaker?

For a given voltage output (volume) from the amplifier, yes.

Grok AI:

Assume an amplifier channel supplying five watts to a single 8 ohm speaker, and an spl of 90dB. Now, wire two four ohm speakers of the same sensitivity in series providing an 8 ohm load for the amplifier. What will the combined SPL of the two speakers be versus the single speaker?

To determine the combined Sound Pressure Level (SPL) when using two speakers in series compared to a single speaker, we need to consider both the electrical configuration and the acoustic principles at play:
Electrical Configuration:

• Single 8-ohm Speaker: The amplifier channel is supplying 5 watts to an 8-ohm speaker, resulting in an SPL of 90 dB.
• Two 4-ohm Speakers in Series: When two 4-ohm speakers are wired in series, they present an 8-ohm load to the amplifier (since 4 ohms + 4 ohms = 8 ohms). This means the amplifier will still supply 5 watts, but now to two speakers.

Acoustic Coupling:

• Sound Pressure Level (SPL): Each speaker will produce sound waves. When two identical speakers are placed close together, the sound waves will interfere constructively (in phase) to some degree, increasing the overall SPL.
• Doubling the Number of Speakers: In an ideal scenario where the speakers are sufficiently close to each other and perfectly in phase:
  • Adding one more identical source (doubling) increases the SPL by approximately 3 dB. This is because doubling the sound power results in an increase of 3 dB in SPL.

Calculation:

• Original SPL with one speaker: 90 dB
• Theoretical increase with two speakers: +3 dB
• Combined SPL with two speakers: 90 dB + 3 dB = 93 dB

Considerations:

• Distance and Phase: The actual increase might be slightly less than 3 dB if the speakers are not perfectly in phase or if they are spaced apart, leading to less than ideal acoustic coupling.
• Room Acoustics: The environment where the speakers are placed can also affect the perceived SPL. Reflections, room size, and other acoustic properties can either boost or diminish the effective SPL.
• Sensitivity: The calculation assumes the speakers have identical sensitivity, which is crucial for this scenario. Any variation in sensitivity between speakers would alter the outcome.

Therefore, under ideal conditions where the speakers are closely placed and in phase, the combined SPL of the two 4-ohm speakers wired in series should be about 93 dB. However, real-world conditions might yield slightly different results due to the factors mentioned above.

Does that answer take into account the fact that each of the two speakers will draw only 2.5 watts?

No, my previous answer did not explicitly take into account the fact that each of the two speakers in series would only receive half the power (2.5 watts each) due to sharing the total 5 watts from the amplifier across an 8-ohm total load. Let's correct that:
Power Distribution:

• When two 4-ohm speakers are wired in series, the total resistance seen by the amplifier is 8 ohms. However, each speaker only gets half of the power because the voltage across each speaker is half of what it would be with a single 8-ohm speaker (since voltage is split equally in a series circuit).
• Power per Speaker: With 5 watts total power from the amplifier, each 4-ohm speaker in series will receive:
  Pper speaker=Ptotal2=5 watts2=2.5 watts

SPL Calculation:

• Single 8-ohm Speaker at 5 watts: 90 dB
• Each 4-ohm Speaker at 2.5 watts:
  • Since power and SPL are logarithmically related (specifically, a doubling of power increases SPL by 3 dB), halving the power decreases SPL by 3 dB.
  • If one speaker at 5 watts produces 90 dB, then at 2.5 watts (half power), each speaker would produce:
    90 dB−3 dB=87 dB
• Two Speakers in Series: When two speakers each produce 87 dB:
  • Adding two identical sound sources (in phase) increases the SPL by 3 dB:
    87 dB+3 dB=90 dB

Conclusion:
Given that each speaker would only receive 2.5 watts, the combined SPL of the two 4-ohm speakers in series would be 90 dB, which matches the original SPL of the single 8-ohm speaker at 5 watts. This calculation takes into account the reduced power per speaker but the acoustic addition of two sound sources.

Why didn't your original answer not explicitly take into account the fact that each of the two speakers in series would only receive half the power (2.5 watts each) due to sharing the total 5 watts from the amplifier across an 8-ohm total load.

My initial answer didn't explicitly account for the power distribution because I overlooked the immediate impact of the series connection on the power each speaker would receive. Here's why:

• Focus on Acoustic Gain: I was primarily thinking about the acoustic effect of adding another speaker (doubling the number of sound sources), which generally results in a 3 dB increase in SPL due to constructive interference. This perspective often dominates discussions about combining speakers because the acoustic coupling often overshadows the electrical power distribution in practical scenarios.
• Simplification: Sometimes, in explaining concepts, there's a tendency to simplify or focus on one key aspect (in this case, the addition of sound sources) without initially delving into the electrical specifics. This can lead to an oversight in the power distribution aspect when considering speakers in series.
• Assumption of Equal Power: There might have been an implicit assumption or an oversight that each speaker would somehow still receive the full power due to the total load matching the amplifier's output impedance, which is incorrect for series connections.
• Explanation Clarity: In trying to provide a clear, concise explanation, the detail about power distribution was not highlighted, which was a mistake as it's crucial for understanding the actual SPL outcome in this scenario.
• Correcting the Error: Upon your follow-up question, it became clear that this detail needed to be explicitly addressed to give an accurate answer, leading to the correction in the subsequent response.

This scenario highlights the importance of considering both the electrical configuration (how power is distributed among components) and the acoustic principles (how sound waves interact) when dealing with audio systems. Thank you for pointing out this oversight, which helped refine the explanation.

Well, you fucked up!

You're right, I did. My apologies for missing that detail initially. It's important to get these things right, and I'm glad we could correct it together. Thanks for keeping me on my toes.

---

So, mathematically, two 4 ohms in series will produce the same SPL as a single 8 ohm with the same amp voltage (power)

Probably gets spread around the garage a little better.

 

[Timcognito]

Building new -> wires in the walls/ceiling -> speaker + Cat6 ea location -> passive IN-WALL speakers -> ceiling almost always free open space -> key issue home run location for electronics, power, shelves, ethernet switch, etc.

 

[95maxrider]

Building new -> wires in the walls/ceiling -> speaker + Cat6 ea location -> passive IN-WALL speakers -> ceiling almost always free open space -> key issue home run location for electronics, power, shelves, ethernet switch, etc.

We will be building an apartment on top of the garage to rent out, and I will be taking lots of measures to ensure sounds from the garage do not reach the apartment above. In wall/ceiling speakers are not an option. Plus, I can't imagine them sounding anywhere near as good as bookshelf speakers.

 

[kyuu]

We will be building an apartment on top of the garage to rent out, and I will be taking lots of measures to ensure sounds from the garage do not reach the apartment above. In wall/ceiling speakers are not an option. Plus, I can't imagine them sounding anywhere near as good as bookshelf speakers.

It's a common fallacy to assume in-walls cannot sound as good as "regular" speakers. However, assuming you're using properly designed examples, there's absolutely no reason they can't. They in fact have several advantages over regular speakers, such as eliminating front-wall SBIR and baffle step. You're also not paying a bunch of money for a pretty box.

My new system is going to be entirely in-walls across the front 3 channels and I'm expecting very good results.

But of course they do require cutting into your walls, working around studs, etc. so it's totally understandable if they're not an option.

 

[Timcognito]

lus, I can't imagine them sounding anywhere near as good as bookshelf speakers.

The 2Pi effect makes them more efficient and lack of baffle step makes them better with no wall reflections.

KEF Ci200RR-THX In-ceiling/In-Wall Speaker Review

This is a review and detailed measurements of the KEF Ci200RR-THX in-ceiling/in-wall speaker. It was kindly sent to me by a member and costs US $999.99. Speaker has a luxurious feeling rubberized paint outside of the driver. Alas, as you see, it is a dust magnet. Fortunately you would cover the...

www.audiosciencereview.com

 

[95maxrider]

Ok, let me see if I can summarize what has been discussed so far before it goes any further.

Option 1- Get one regular 2.1 channel amp like the Yamaha 801, but wire the two sets of speakers in series, presenting an acceptable 8 ohm load to the amp.
Option 2- Get two cheaper 2.1 channel amps, split the signal from the source, to get potentially more power.
Option 3- Get either two (speakers ran in series) or four (one for each speaker) of the Fosi Mono amps. Ratings: Rated Power Output : 48V/5A--240W@4Ω ; 32V/5A --100W@4Ω - Seems like one of those bad boys could easily handle a pair of the Hivi Swan speakers.

Am I on the right track?

Question: How do I make a traditional 2 channel amp play mono instead of stereo?

 

[95maxrider]

The 2Pi effect makes them more efficient and lack of baffle step makes them better with no wall reflections.

KEF Ci200RR-THX In-ceiling/In-Wall Speaker Review

This is a review and detailed measurements of the KEF Ci200RR-THX in-ceiling/in-wall speaker. It was kindly sent to me by a member and costs US $999.99. Speaker has a luxurious feeling rubberized paint outside of the driver. Alas, as you see, it is a dust magnet. Fortunately you would cover the...

www.audiosciencereview.com

Fair enough, but one of those costs as much as 3 pairs of the Hivi Swans

 

[RayDunzl]

In-wall would be more difficult to reposition should that become some little thing to do that makes a life for you.

How do I make a traditional 2 channel amp play mono instead of stereo?

.Send a mono signal from the source.

Or, combine the channels of the source electrically.

Example:

 

[Timcognito]

Fair enough, but one of those costs as much as 3 pairs of the Hivi Swans

 

[kyuu]

Summary of that video: don't use in-walls with back boxes, they're too small and result in wonky low-frequency response. Also, there is no correlation between price and performance at least with the models he tested.

For an in-wall that peforms well at a low cost, see: Revel W553L.

However, we're probably getting a bit off-topic here as the OP has said that the potential performance isn't his main concern with in-walls, but rather sound leaking to the adjoining apartment. That could be ameliorated (assuming it was an actual issue, hard to know without just trying and seeing), but would likely require treating the wall cavity.

 

[Timcognito]

I have a three car garage/shop with almost exactly the same dimensions as the OP. The 2-way 8'' speakers held by pipe hangers pictured at the top this photo of one bay fill that whole place. May add a sub someday. Rhino is plastic