Speaker filler

[Woahduds]

I just finish building a pair of speakers and i wonder if adding some sort of foam or filler in the box will improve the low end

[themctipers]

@Ryan_Vickers (explain your 'foam' and 'sponge' here)

[Woahduds]

1 minute ago, themctipers said:

@Ryan_Vickers (explain your 'foam' and 'sponge' here)

https://www.parts-express.com/acoustic-sound-damping-foam-1-1-2-x-24-x-18-ul-94--260-516

https://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-sound-damping-material-1-lb-bag--260-317

these stuff 

[Himommies]

9 minutes ago, Woahduds said:

https://www.parts-express.com/acoustic-sound-damping-foam-1-1-2-x-24-x-18-ul-94--260-516

https://www.parts-express.com/acousta-stuf-polyfill-speaker-cabinet-sound-damping-material-1-lb-bag--260-317

these stuff 

IMO it's fine to probaly just buy a speaker grill and call it a day

[Phate.exe]

Just now, Himommies said:

IMO it's fine to probaly just buy a speaker grill and call it a day

A speaker grill has nothing to do with OP's question.

 

But yes.  From my car audio days, adding polyfill to the enclosure can make it act like you're working with a larger box, and and will also help to reduce resonances that would make your speaker have a weird peak in it's frequency response (on a subwoofer, you'd notice the thing become obnoxiously boomy at certain frequencies).

[Woahduds]

1 minute ago, Phate.exe said:

A speaker grill has nothing to do with OP's question.

 

But yes.  From my car audio days, adding polyfill to the enclosure can make it act like you're working with a larger box, and and will also help to reduce resonances that would make your speaker have a weird peak in it's frequency response (on a subwoofer, you'd notice the thing become obnoxiously boomy at certain frequencies).

did you notice changes in the lower frequencies? like sub bass

[Phate.exe]

Just now, Woahduds said:

did you notice changes in the lower frequencies? like sub bass

I was only really using it on subwoofer enclosures, but yeah, because the sealed box I have my 2 12in kenwoods in was a bit on the small side, polyfill did improve their sound quality.  When I stuffed the box I'm using with a single 12in kicker, it greatly helped eliminate a weird boomy resonance (which was fun if you wanted to be obnoxious with bass, but was annoying to tune to sound nice.

 

The 2x12 Kenwoods didn't really have an issue with it like the single 12, but I did notice apparently flatter frequency response from my subs after that, which made them much easier to tune.

[unknownmiscreant]

20 minutes ago, Himommies said:

IMO it's fine to probaly just buy a speaker grill and call it a day

If the speaker boxes are sealed, you definitely want to place something along the lines of speaker box filler of fibre glass house insulation inside the box. The presence of the filler makes the enclosure 'appear' larger to the individual drivers, this lowers their resonance, making more low-end.

 

It will also help reduce speaker box resonation, especially for subwoofers.

 

If you want to improve low end and have a subwoofer, I would recommend getting and active sharp roll off crossover at just above the -3db point of your midrange. That made the biggest difference to the low end on the stereo system I made a couple of years ago. If you want even more low-end, add a linkwitz transform circuit to equalize the sub. I managed to get an 8" driver with flat frequency response down to 30Hz. However you need some serious power requirements. I have a true 120W RMS amp output on the sub (achieved with BTL). (Don't confuse this with the PMPO marketing crap)

14 minutes ago, Woahduds said:

did you notice changes in the lower frequencies? like sub bass

Speaker grills are pretty useless and can actually change the sound. (probably not if you get decent ones) I personally would only bother if you have a cat/small person who will poke the speakers.

[unknownmiscreant]

7 minutes ago, Phate.exe said:

I was only really using it on subwoofer enclosures, but yeah, because the sealed box I have my 2 12in kenwoods in was a bit on the small side, polyfill did improve their sound quality.  When I stuffed the box I'm using with a single 12in kicker, it greatly helped eliminate a weird boomy resonance (which was fun if you wanted to be obnoxious with bass, but was annoying to tune to sound nice.

 

The 2x12 Kenwoods didn't really have an issue with it like the single 12, but I did notice apparently flatter frequency response from my subs after that, which made them much easier to tune.

If you wanna be obnoxious with bass, equalize your sub. With a fair bit of work, you should be able to get 2x12" below 15Hz with flat frequency response. Having said that, you may well need a new amplifier. Around 300W RMS per speaker is a minimum is this department. Also, the kinds of voltages across the speaker terminals with that kind of amplifier have a very real potential of killing you!!

 

Wierd boomy resonances suck!! The speaker set that came prre installed in our house has this, it is very responsivve around 100-120hz, but nowhere else.

 

I have never tried with or without filler, in either my sub or midrange/tweeter enclosures. It was so cheap, I just bought a sheet of it straight up, and it was just enough to fill all my boxes. If you do get foam, make sure it is open cell, as other wise it will probably degrade sound quality. The acrylic 'wool' i bought was very easy to work with, and didn't leave alot of mess.

[Phate.exe]

2 minutes ago, unknownmiscreant said:

If you wanna be obnoxious with bass, equalize your sub. With a fair bit of work, you should be able to get 2x12" below 15Hz with flat frequency response. Having said that, you may well need a new amplifier. Around 300W RMS per speaker is a minimum is this department. Also, the kinds of voltages across the speaker terminals with that kind of amplifier have a very real potential of killing you!!

Haha, I'm pretty much done messing with that system, it's more than obnoxious enough as-is.  It's pretty well-balanced (especially after I added the 6.5's to the rear doors), but I've got another EQ setting tuned for annoying people.  Low 120-decibel range tuned for sound quality, and will do 130 if you tune things to piss people off.

 

It's a pair of Kenwood W3011's in a slightly-too-small sealed box (hence why I stuffed it with polyfill), with size considerations mostly being based around nicely fitting between the rear shock towers of my old 1997 Accord sedan.  I had purchased the amp when I was originally planning to run a pair of 10's instead, so it's a bit undersized but still kicks out more than the rated 500W RMS without clipping if you can keep it cool.  The subs would be totally happy with double the power I'm throwing at them currently, but it's loud enough and it's in a very small car.

 

I put the 12's in the car in 2008, because that's what highschool kids do.  While I was a broke college kid with plenty of time on my hands, I was given a few sets of the factory Bose speakers and amps out of a 90's Maxima, figured out the wiring pinouts to make them happy, and got those working.  Overall, I actually like the junkyard bose speaker/amp combos more than the Alpine TypeS component set I had, and installed a set in the front doors, rear doors (using door cards from an accord wagon), and in the rear deck.

 

Just running whatever Pioneer single din I bought for $200-ish back in 2008, I think it's a DEH-P3000.

[vanished]

1 hour ago, themctipers said:

@Ryan_Vickers (explain your 'foam' and 'sponge' here)

I have no idea what's going on here but I'm pretty sure it has nothing to do with what I was telling you about (ports on a sub and plugging them)

[unknownmiscreant]

2 minutes ago, Phate.exe said:

snip

Yeah, keeping amps cool is rather hard, mine struggles for thermals when I crank it, but thats mainly as I only designed the cooling system to handle the midrange amps. Adding the BTL sub amps really didn't help thermals, so now I have a (thankfully quiet) fan with thermistor control. Next amp I build will be water cooled, probably with something along the lines a a RAM block from EKWB, and I will also have all the micro controllers for input selection etc built into one chassis. Live and learn I guess.

 

1000W amp for any speaker is somewhat ludicrous. At that point I personally would start looking for higher efficiency drivers, as when running any driver over 100W ish you start running into power compression issues and the laws of diminishing returns. I have never really looked into car audio, I've stuck to mains powered hi-fi stuff, where power supply is a bit easier, I have built every part of my stereo (including amps, crossovers etc from scratch.) Also I don't have a car.

 

Being obnoxious with bass can be somewhat amusing, even with flat frequency response, most of my family get triggered by my 8" sub when we watch movies. Maybe thats due to movies over-accentuating bass to try compensate for other peoples shit systems.

 

What parts are you using from the bose set? My (fairly limited) experiences of bose products have not been overly positive. I would be interested to know what you found that was of use.

[unknownmiscreant]

2 minutes ago, Ryan_Vickers said:

I have no idea what's going on here but I'm pretty sure it has nothing to do with what I was telling you about (ports on a sub and plugging them)

Plugging ports on a sub?? Generally if the subwoofer is a decent brand, the ports will have been tuned to generate a usually fairly decent frequency response. You can try plugging the ports, make sure whatever you do is 100% REVERSIBLE!!!! Last time I tried plugging speaker ports it made everything worse. There are benefits to sealed cabinets, however I would generally recommend leaving ports alone (unless they are tune able) as unless the speaker was very cheap, resonances etc will have been setup from the factory. Any modifications have a fair likelihood of being detrimental.

 

For box filler material, I would recommend either fiberglass house insulation, or something along the lines of material that has been designed as a speaker box filler. I got a 1x1.5m sheet for 10-15USD. Probably stay away from foam or sponge, as it is likely to be more expensive and has the potential to be closed cell, which would degrade performance.

 

I would only go with the house insulation if you are comfortable with the mess it is sure to make.

[vanished]

3 minutes ago, unknownmiscreant said:

Plugging ports on a sub?? Generally if the subwoofer is a decent brand, the ports will have been tuned to generate a usually fairly decent frequency response. You can try plugging the ports, make sure whatever you do is 100% REVERSIBLE!!!! Last time I tried plugging speaker ports it made everything worse. There are benefits to sealed cabinets, however I would generally recommend leaving ports alone (unless they are tune able) as unless the speaker was very cheap, resonances etc will have been setup from the factory. Any modifications have a fair likelihood of being detrimental.

There are some very high end subs that come with foam plugs to be added or removed at your leisure 

[unknownmiscreant]

9 minutes ago, Ryan_Vickers said:

There are some very high end subs that come with foam plugs to be added or removed at your leisure 

At the high end, subwoofers have tuneable ports, and doing some tuning can improve sound-quality. I'm not denying that, however most of time when people are told to plug their sub-ports it is for a fairly low-end sub that has not been designed to have that happen, so the results can be varied. Hence the following comments:

12 minutes ago, unknownmiscreant said:

You can try plugging the ports, make sure whatever you do is 100% REVERSIBLE!!!!

13 minutes ago, unknownmiscreant said:

I would generally recommend leaving ports alone (unless they are tune able)

 

[Ahoy Hoy]

It should do absolutely nothing to the low end frequencies. It will affect higher frequencies which will then trick you into thinking its done something with the low.

There is a really simple rule for foam and what frequencies it will affect. It has to be greater then a quarter of the wave length to have a affect.
100Hz is 3.5 meters. so thats 90cms of foam. 20Hz is 55 meters, thats a lot of foam.

[loculus]

4 hours ago, unknownmiscreant said:

At the high end, subwoofers have tuneable ports, and doing some tuning can improve sound-quality. I'm not denying that, however most of time when people are told to plug their sub-ports it is for a fairly low-end sub that has not been designed to have that happen, so the results can be varied. Hence the following comments:

 

This is totally besides the point, just FWIW the ~$400 Hsu Research VTF-1 MK3 (their cheapest model) has a variable tuning port system. That's not entry level in sub land but far from the high end.

[unknownmiscreant]

5 hours ago, loculus said:

This is totally besides the point, just FWIW the ~$400 Hsu Research VTF-1 MK3 (their cheapest model) has a variable tuning port system. That's not entry level in sub land but far from the high end.

I'm really not sure what your point is. Or why what I said is beside the point. As far as I can tell your only point is:  "the cheapest HSU sub [which you state yourself is not entry level] has tuneable ports." Are you solely disagreeing with my use of the incredibly arbitrary and undefined terms 'high end' and 'low end'? I was intending 'high-end' to encompass products exactly like the one you mentioned. Did you even read what I posted? I stated very clearly that if the sub has been DESIGNED to be tuned, (as the one you posted has) that tuning it is worthwhile. My points about trying to tune a sub that has not been designed to be tuned and not making any irreversible modifications were pointers from my personal experience trying to improve speakers and from other audio websites. I have never plugged the ports on a speaker and thought that it improved the overall sound stage, but the results really depend on each individual speaker. For sure it is worthwhile to try plugging the ports, but don't go around gluing them shut, in case the ports are required for the speaker to resonate properly inside the enclosure, and create the desired sound stage. If this is the case you will feel like a right mug having ruined your sub woofer by gluing the ports shut.

 

 

10 hours ago, Ahoy Hoy said:

It should do absolutely nothing to the low end frequencies. It will affect higher frequencies which will then trick you into thinking its done something with the low.

There is a really simple rule for foam and what frequencies it will affect. It has to be greater then a quarter of the wave length to have a affect.
100Hz is 3.5 meters. so thats 90cms of foam. 20Hz is 55 meters, thats a lot of foam.

Would you care to explain why? Based off my understanding of physics, it seems like you are going for something about resonance inside the box. A 55m speaker box seems somewhat ludicrous. I may be wrong, but I always thought the main purpose of foam was to reduce unwanted vibrations.

[loculus]

6 hours ago, unknownmiscreant said:

I'm really not sure what your point is. Or why what I said is beside the point. As far as I can tell your only point is:  "the cheapest HSU sub [which you state yourself is not entry level] has tuneable ports." Are you solely disagreeing with my use of the incredibly arbitrary and undefined terms 'high end' and 'low end'? I was intending 'high-end' to encompass products exactly like the one you mentioned. Did you even read what I posted? I stated very clearly that if the sub has been DESIGNED to be tuned, (as the one you posted has) that tuning it is worthwhile. My points about trying to tune a sub that has not been designed to be tuned and not making any irreversible modifications were pointers from my personal experience trying to improve speakers and from other audio websites. I have never plugged the ports on a speaker and thought that it improved the overall sound stage, but the results really depend on each individual speaker. For sure it is worthwhile to try plugging the ports, but don't go around gluing them shut, in case the ports are required for the speaker to resonate properly inside the enclosure, and create the desired sound stage. If this is the case you will feel like a right mug having ruined your sub woofer by gluing the ports shut.

 

My comment was a brief aside (my comment being largely outside of what is relevant for his discussion, which is your point about generally not messing with ports that aren't designed to be tuned), as in not disagreeing with the substance of anything prior, that tunable subs exist far below the high end of the market. It's an arbitrary distinction but maybe some have seen these.

 

It was supposed to be a clarifying example of exceptions to the generalized statements about high vs. low end subs and which features they might have, but apparently nobody took it that way so nevermind.

[Ahoy Hoy]

7 hours ago, unknownmiscreant said:

Would you care to explain why? Based off my understanding of physics, it seems like you are going for something about resonance inside the box. A 55m speaker box seems somewhat ludicrous. I may be wrong, but I always thought the main purpose of foam was to reduce unwanted vibrations.

Thats exactly the point it is ludicrous which is why people dont make huge cabinets like that and its also why sub dont normally have foam in.

[unknownmiscreant]

4 hours ago, loculus said:

My comment was a brief aside (my comment being largely outside of what is relevant for his discussion, which is your point about generally not messing with ports that aren't designed to be tuned), as in not disagreeing with the substance of anything prior, that tunable subs exist far below the high end of the market. It's an arbitrary distinction but maybe some have seen these.

 

It was supposed to be a clarifying example of exceptions to the generalized statements about high vs. low end subs and which features they might have, but apparently nobody took it that way so nevermind.

Apologies for the misunderstanding. I don't have a very good handle of what pre-assembled high end audio products that are out there. mainly due to the cost . 

 

3 hours ago, Ahoy Hoy said:

Thats exactly the point it is ludicrous which is why people dont make huge cabinets like that and its also why sub dont normally have foam in.

That looks accurate for ported enclosures, where resonance is key to creating the frequency response. My points were more to do with sealed enclosures, where resonance is quite high, so equalization is required to get a flat frequency response, at the expense of max SPL. I have a max DC gain of 9db on the sub feed, I can get 100db (at 1m) at 30Hz.

 

Thanks for clearing that up.

[Ahoy Hoy]

19 hours ago, unknownmiscreant said:

That looks accurate for ported enclosures, where resonance is key to creating the frequency response. My points were more to do with sealed enclosures, where resonance is quite high, so equalization is required to get a flat frequency response, at the expense of max SPL. I have a max DC gain of 9db on the sub feed, I can get 100db (at 1m) at 30Hz.

It would be silly putting it in a ported speaker since it just fall out (when people do they then put a grill infront or inside the port). Its has the same affect on ported or unported since that doesnt affect how the foam works. It only affects higher frequencies so if you are going to get resonance at higher frequencies it is worth while doing, but if your not theres no point.
There are websites to calculate resonance frequencies, just give something like calculate resonance frequncy in a speaker cabinet into google.

[unknownmiscreant]

6 hours ago, Ahoy Hoy said:

It would be silly putting it in a ported speaker since it just fall out (when people do they then put a grill infront or inside the port). Its has the same affect on ported or unported since that doesnt affect how the foam works. It only affects higher frequencies so if you are going to get resonance at higher frequencies it is worth while doing, but if your not theres no point.
There are websites to calculate resonance frequencies, just give something like calculate resonance frequncy in a speaker cabinet into google.

Thats makes sense. I have never seen foam/wool in ported designs. 

 

I'm really not sure about what happens for sealed enclosures. My understanding (possibly wrong) was that the larger the box, the lower the resonance, and the presence of the filler made the box 'appear' larger. Hence reducing resonance and the amount of DC gain required to equalize it.

 

I'm going to do some more research into this, and probably try measuring the resonance of my sub with and without the filler. I'll let you know what the results are.

 

I used this to fill my speakers. Its basically acrylic house insulation.

https://www.jaycar.co.nz/650gsm-acrylic-speaker-dampening-material/p/AX3694

[spwath]

3 hours ago, unknownmiscreant said:

Thats makes sense. I have never seen foam/wool in ported designs. 

 

I'm really not sure about what happens for sealed enclosures. My understanding (possibly wrong) was that the larger the box, the lower the resonance, and the presence of the filler made the box 'appear' larger. Hence reducing resonance and the amount of DC gain required to equalize it.

 

I'm going to do some more research into this, and probably try measuring the resonance of my sub with and without the filler. I'll let you know what the results are.

 

I used this to fill my speakers. Its basically acrylic house insulation.

https://www.jaycar.co.nz/650gsm-acrylic-speaker-dampening-material/p/AX3694

i have seen it in ported speakers with no grill. It stays in fine.