Boxing in rear deck speakers ?

[Brewzer67]

As an audiophile of many years I can say from experience that you always want an amp which has more power than you need for driving your speakers to the volume levels you want. If you don't, you will always drive the amp to clipping which is the kiss of death for a speaker. Way more than overpowering them. I have routinely had speakers with an RMS rating of 60 watts survive use with an old Sansui 9090 (110 watts/channel) or Technics SA-1000 (330 watts/channel) which both substantially exceed the RMS rating of the speakers. The key is to listen to them and scale back as soon as you hear any slight strain. I have also seen speakers of a 100 watt RMS rating die at the hands of a 50 watt amp because it was driven to its max and was probably at 20% distortion or more due to clipping. Clean power is safe, clipped and distorted is not. Marantz made a killing in the 70's and 80's selling amps that delivered more unclipped power than they were rated for. JMHO

 

[j-c-c-62]

As an audiophile of many years I can say from experience that you always want an amp which has more power than you need for driving your speakers to the volume levels you want. If you don't, you will always drive the amp to clipping which is the kiss of death for a speaker. Way more than overpowering them. I have routinely had speakers with an RMS rating of 60 watts survive use with an old Sansui 9090 (110 watts/channel) or Technics SA-1000 (330 watts/channel) which both substantially exceed the RMS rating of the speakers. The key is to listen to them and scale back as soon as you hear any slight strain. I have also seen speakers of a 100 watt RMS rating die at the hands of a 50 watt amp because it was driven to its max and was probably at 20% distortion or more due to clipping. Clean power is safe, clipped and distorted is not. Marantz made a killing in the 70's and 80's selling amps that delivered more unclipped power than they were rated for. JMHO

Well, it appears that controversy is finally settled based on who has awarded you the first "like" on your above reply.
I'll add mine.
My experience being in the industry over 5+ decades has been in nearly every case, listening to two different solid-state amps of the same design/manufacturer/etc, yet having different power ratings, with the output level say at only 5% of the lower amps rating, and both tested at the same listening level, the larger amp ALWAYS sounds better.
That does not mean I am suggesting one should seek to use a 5,000 watt amp to power a 5 watt speaker, which would not be cost/nor power consumption/weight/size wise efficient, dangerous to the speaker and of likely diminishing returns, etc

 

[Unkle Krusty]

I do not know about that.
But, what I do know is my 007 pickup, has a powered sub woofer and two big speakers behind the seats. The seller did not know they were there, and neither did I. A large fuse and some tuning by the stereo guy and I can make a lot of noise.
The speaker specs should give the volume. 4.41 cubic feet for the 12 inch replacement I have for my shed speakers.

For post 21. I think my GAS Ampzilla is getting tired. I will probably be looking for a replacement later this year.

 

[j-c-c-62]

I do not know about that.
But, what I do know is my 007 pickup, has a powered sub woofer and two big speakers behind the seats. The seller did not know they were there, and neither did I. A large fuse and some tuning by the stereo guy and I can make a lot of noise.
The speaker specs should give the volume. 4.41 cubic feet for the 12 inch replacement I have for my shed speakers.

For post 21. I think my GAS Ampzilla is getting tired. I will probably be looking for a replacement later this year.

You can't realistically compare a typical 6x9 car speaker with any 12" in any way except that they both produce sound, ignoring what the particular 12" speaker is designed for and intended use, ie, horn loading, ported bass reflex, acoustical suspension, infinite baffle, passive radiator, midrange, guitar/musical instrument, coaxial, Sub, etc .
Other than that, I will stay on topic regarding rear shelf mounted 6x9 car speakers.

 

[Nacho-RT74]

I’m sound tech (or supodselly I am LOL)

My first question is… why?

The only reason to build an enclosure cabinet and actually win something is getting the box correctly tuned to get a bass reflex build into the enclosure to win some dBs from the sound coming from back of the speakers (yes, speakers produces same sound on both sides, but 180* out of phase) and get the bass reflex projected to the front or cab correctly phased. If you don’t get that, better get it simply hanging out from rear tray as an infinite baffle as originally is.

Otherwise a sealed enclosure produces a back pressure able to get absorbed the cone movement reducing sound pressure, unless you include some venting holes on back… but still will be winning nothing aside maybe protect the assembly?

 

[Nacho-RT74]

About speakers and amps balance.

NORMALLY what is correct is get an amp 10x more powerful than what speaker is able to handle but are we talking about PEAK? or RMS?. All in all, the best is an amp able to produce the full peak power without electronic distortion AND the speaker able to handle the transitory peaks without going to excursion (acoustic or mechanical distortion)

The electronic distortion creates square waves which becomes sinusoidal audio waves into DC. This keeps speaker coils fully out of the magnet out being constantly energized up to get heat and burnt.

The mechanic distortion gets damaged the cone itself but still keep safe the coil.

Now… a 200w amp supplying a 40w speaker? Sure, I can see it fine. At the end your hearing must be able to say stop! Is distorting! You can use a 1000 watts amp too! Or 20 watts amp. Is your hearing capacity able to distinguish how much is enough to stop?

The kind of music is also something to be considered. Trash metal? Jazz?

 

[Nacho-RT74]

On a side note:

Not even reconigzed audio brands (such as Harman-Kardon and others) taking care of the audio equipments on premium car brands actually build speaker enclosures on their assemblies. They all assume the panels where they are mounted as “infinite baffles”… without even incorporated bass reflex systems to the car.

 

[j-c-c-62]

I’m sound tech (or supodselly I am LOL)

My definition, anybody two working ears is a "sound tech". The difference is in their training to understand what they are hearing and why.
We all started out knowing absolutely nothing, and we all are usually on the same path hopefully moving forward, but always at a different place.
I make a conscious concerted effort to share what I have learned over the decades, that I wished would have been offered to me.
Getting some to actually listen (pun intended) can be a chore sometimes.

 

[YY1]

Let's talk about $10,000 speaker wire.
Because you really can hear a difference between that and lamp cord.

...or so some people say.

 

[j-c-c-62]

Let's talk about $10,000 speaker wire.
Because you really can hear a difference between that and lamp cord.

...or so some people say.

It's called "confirmational bias" and easy to prove with a simple double-blind A/B test.
Lamp cord is far from ideal, but it's biggest downside is simply too small of guage , and easy to resolve.
If they really want ultimate speaker wire, pure silver is it, and less than $10K, good luck of anyone over 30 ever being able to hear the difference

 

[68 Sport Satellite]

...in nearly every case, listening to two different solid-state amps of the same design/manufacturer/etc, yet having different power ratings, with the output level say at only 5% of the lower amps rating, and both tested at the same listening level, the larger amp ALWAYS sounds better.
That does not mean I am suggesting one should seek to use a 5,000 watt amp to power a 5 watt speaker, which would not be cost/nor power consumption/weight/size wise efficient, dangerous to the speaker and of likely diminishing returns, etc

I agree on both statements above. I think we're generally both in agreement and getting a little tripped up on lack of complete explanations earlier on. Thanks for carrying on the dialogue. You were saying above "in nearly every case the larger amp always sounded better". So there were some cases where the smaller amp sounded better? Was that due to other variables in the smaller amp construction or something else?

Back to the OP's original question - there is not going to be much benefit in boxing your 6x9 size speakers while hanging from the rear deck.

As for powering those 6x9's with an external amp:
@j-c-c-62 : you've provided some clarity on two points we can agree on and have some discussion - I agree on a larger amp set to 5% of the lower amps rating sounding better in general. Problem is, when using the car stereo volume dial, we generally would like to have a usable range with the turn of the knob and not hear speaker distortion only half-way up, which makes me also agree with your not suggesting a 5000w amp to power a 5W speaker. Too little power from amp to speaker can be bad if the volume is turned up too loud, and too much power from amp to speaker can also be bad if volume is turned up too loud (for different reasons).

I know some amps have their own output range switch or knob, but those don't always provide enough control due to their own range, sensitivity, or lack thereof. So, it's a balancing act - use an amp with enough CLEAN power for the speakers so they're not sounding like crap when turned up, but low enough power so the car stereo volume control can be used with a wider overall range. Those reading here also need to remember like you said in the subsequent post - a 6x9 is not built the same as and does not behave like a 12" for sound reproduction, so some greater care in choosing the correct amplifier power for a 6x9 is appropriate since the 6x9 is often 2-way or 3-way with tweeters involved and also has a smaller primary voice coil and cone.

Based on your industry experience and customer feedback, is there a general rule of thumb for selecting a safe good sounding amp wattage to power a pair of 6x9's and still have a wide usable range on the car stereo volume control? I do know in that first example I gave, the 200W Sanyo amp connected to the pair of Jensen 6x9's that were both rated at 200W was too much power. aAfter installing it I took it to an audio shop and after evaluating they agreed. Was the other smaller amp I had on hand and had success with the best choice to replace the 200W amp? Maybe not - but it was good enough for my particular combination and I didn't have funds to experiment at the time.