Where's the bass from an 18" Audiobahn AW1805Q in a 12cf vented enclosure?

[FairfaxStu]

Philip,

I have a very, very similar setup to yours. I have a single JBL-2245H in a 13.18 cu. Ft. vented enclosure (internal volume without subtracting space for driver, bracing, and ports). The major difference is that I have 2x 6" ports that are 15" long each. I am powering it with a bridged Crown CE-2000 which should be about 1325 watts.

I am extremely pleased with the performance as it has nice low frequency extension, smoothness, and loudness in my opinion. Like you, I like my system to be loud (all of my other speakers are Klipsch Legacy series). Despite this, I have only managed to blow the woofer one time in the past 15 years. This was as a result of over excursion (as you know well) while listening to a Rap DVD - Dr. Dre's Up in Smoke Tour. After this lesson, I picked up 2 more 2245's that I keep around for quick replacement. Thankfully, I have never had to use them.

Anyway, I am curious as to how large your listening room is, how loud you like to listen to music/movies, and the rest of your setup (mains). It would appear that my enclosure is tuned a fair amount lower than is yours but I am not sure this would have made a significant difference anyway.

I built 2 of these for a good friend for his home theatre (larger listening space) with the exact same setup - enclosure+2245+crown. He blew them up a couple of times and then changed out the 2245's for a different driver (super expensive as I recall). After retuning the cabinet by extending the ports, he has all of the bass he can handle so much so that he has done some minor structural damage to his house by playing them wicked loud. I can see if I can pull up the drive info and perhaps some pics if you are interested.

-Stu

 

[Max Caliber]

I don't like vented designs period, so in my opinion - yes.

Well theAnonymous1, if you don’t like vented enclosures and you don’t like passive radiators, what would you prefer to use to get very low frequencies, when you have the 12^3 foot box, the place to locate it, the amplifiers to drive it, and a wife that doesn’t mind it? I’m all ears.

Philip

 

[Max Caliber]

"It’s the earth shaking rumble that I am looking for, those frequencies between 10 and 25Hz that shake the foundation."

"what sub would you suggest I use in this situation that will generate the deep frequencies I’m looking for?"

Bass shakers?

Clark Synthesis TST429 Platinum Transducer | Parts-Express.com

Hello Adam

And just what do you want me to do with the bass shakers? Recall I have a 12^3 foot box that is just waiting for a decent driver. For the shaker, I would have to put one under each chair, but even this would not shake the foundation, unless I dig a hole under my house and embed it into the concrete of my basement. And even then I don’t think that this would give the results I’m looking for.

Thanks for your unusable solution

Philip

 

[tb46]

Air Duct v. Passive Radiator

Hi Philip,

Basically, only sealed enclosures will not unload below the tuning frequency. That's not really a matter of argument any more, so, if you insist on running without a low cut (high pass) you will generate overexcursion, and damage the driver, or you will have to limit the input power. The drop in SPL below the lower impedance peak in a BR results from the port output being out of phase with the driver's output, driving the enclosure into this range without high pass is not useful, and it does not matter if the port is a passive radiator or an air duct.

You could use a tapped horn enclosure, but that would require at least 450 liter (v. your present 340 L). The tapped horn will outperform a bass reflex, but neither will have useful output to 10 Hz. Maybe take a look over at the AVS forum and the experiences people had with the DTS-10, and their other subwoofers:

Danley DTS-10 "Super Spud" DIY kit - AVS Forum

Regards,

 

[theAnonymous1]

Well theAnonymous1, if you don’t like vented enclosures and you don’t like passive radiators, what would you prefer to use to get very low frequencies, when you have the 12^3 foot box, the place to locate it, the amplifiers to drive it, and a wife that doesn’t mind it? I’m all ears.

Philip

I don't know, how many 12" holes can you cut in it? You could use the left over wood to plug to vent holes.

You must really love this box BTW.

 

[tb46]

Hi again,

A long time ago, I used to run 2 ea. sealed 2'x2'x2' w/ 4 x 10" ea., and I still couldn't hear 10Hz, but they did shake the walls .

Regards,

 

[FairfaxStu]

Philip:

As promised in my previous post, here is what we did for a good friend of mine. He had the same issues a) being a bassaholic 2) blowing up JBL-2245H's. The following link is the problem as expressed on a different forum:

HELP! I keep blowing my JBL 2245H subs - AVS Forum

This link to the solution - different subs:

TC Sounds PA-5000 18" came in today! - AVS Forum Archive 2

With these playing loud, the bass will actually blur your vision and crack your drywall. I have never heard anything like it, even at a concert. Sadly, that same driver is no longer available but the manufacturer website does seem to have a compelling substitute.

-Stu

 

[Max Caliber]

Philip,

I have a very, very similar setup to yours. I have a single JBL-2245H in a 13.18 cu. Ft. vented enclosure (internal volume without subtracting space for driver, bracing, and ports). The major difference is that I have 2x 6" ports that are 15" long each. I am powering it with a bridged Crown CE-2000 which should be about 1325 watts.

I am extremely pleased with the performance as it has nice low frequency extension, smoothness, and loudness in my opinion. Like you, I like my system to be loud (all of my other speakers are Klipsch Legacy series). Despite this, I have only managed to blow the woofer one time in the past 15 years. This was as a result of over excursion (as you know well) while listening to a Rap DVD - Dr. Dre's Up in Smoke Tour. After this lesson, I picked up 2 more 2245's that I keep around for quick replacement. Thankfully, I have never had to use them.

Anyway, I am curious as to how large your listening room is, how loud you like to listen to music/movies, and the rest of your setup (mains). It would appear that my enclosure is tuned a fair amount lower than is yours but I am not sure this would have made a significant difference anyway.

I built 2 of these for a good friend for his home theatre (larger listening space) with the exact same setup - enclosure+2245+crown. He blew them up a couple of times and then changed out the 2245's for a different driver (super expensive as I recall). After retuning the cabinet by extending the ports, he has all of the bass he can handle so much so that he has done some minor structural damage to his house by playing them wicked loud. I can see if I can pull up the drive info and perhaps some pics if you are interested.

-Stu

Hi Stu

My heart goes out to you, blowing a JBL 2245 is such a pain , I consider this driver probably the best woofer ever made. This driver has an incredible sonic presence to it that never seems to distort unless it’s really overdriven, and with its 300watt RMS 600watt peak capability it’s pretty hard to get to those distorting levels in a home environment. Unfortunately, a good woofer is not automatically a good sub-woofer, thus it’s not suitable for a HT use. A point that is often not clear with this driver is that it’s Xmax (10mm) is also it’s mechanical Xlim, meaning that below its tuned frequency the cone becomes unloaded resulting in the coil bottoming out.

Knowing a bit about speakers (I was at one time the JBL service manager for Canada in the 70s) I immediately stopped using the driver after the first occurrence of this unmistakable effect, and looked for a replacement driver thus saving the driver from damage. I’ve tested the 2245 and it still performs within its specifications. This is where the Audiobahn AW1805Q was purchased as the replacement for the 2245 but unfortunately I have not been able to get the performance out of it that its specs seem to say it’s capable of.

My basement is “L” shaped with about 2240^3 feet. The long dimension is about 22’ and the main width is about 10’, the height varies but it’s about 8 feet at its max. The processor is an 8.1 Yamaha VX3300 (I think) connected to 8 speakers and one sub.

For my mains I have 2x (three-way) ESS AMT-3 rock monitors that have been modified to house 1x 12” driver (instead of the 2x 10” drivers) with 3x passive radiators, which are tuned to 20Hz. The low-mid is a 6.5” GP driver and with the large Hiel for the upper mids and highs (more like ultra highs). The impedance is 4ohms for each driver. The entire box is electronically X-overed with 2x Yamaha P2200 power amps for the mids and highs and a Yamaha CP2000 for the bas driver. The P2200 amp is rated at 235watts RMS into 8ohms and 300 watts into 4ohms (I doubt it) per channel and the CP2000 is rated at 450watts at 8 ohms, 650 at 4ohms, and 1000watts 2ohms per channel

The rears are special DIY built 3-way units that are an enlarged version of the ESS rock monitors. They have a 5.5^3 foot (vented) volume with two Max-Caliber 12” bass drivers in each rear also tuned to 20Hz (thus far I we have a total of 6x 12” bass drivers in my basement). The mids and the highs are the same as the front mains. Again this is electronically X-overed with 2x Yamaha P2200 power amps for the mids/highs and 2x more CP2000 power amps for the two 12” bass drivers (4 amps per box).

The front and rear centers are by JBL (presently I don’t recall the model number) where I replaced the crappy little twitter with the nice bullet driver. They are now two-way electronically X-overed with two 2x Yamaha P2200 power amps driving them.

The Side effects are Small JBL units (again I forgot the model number) driven by a single Yamaha P2200 power amp (no E-x-over).

The Audiobahn AW1805Q sub-woofer is driven by a Yamaha P7000 power amp that is wired in a bridge mono mode giving 2200 watts into 8ohms.

The 4x electronic crossovers are all DBX 123XL units using as much as possible balanced feeds, (it’s very hard on a big system such as this to keep the hum down).

With a system such as mine, if I push the amps to 10 watts on their peak reading meters you would be forced to leave the room. I don’t usually play the system that loud but what it’s missing is the really deep SUB bass that I am trying so hard to get. It was there with the JBL but I know that the driver would have been destroyed if I left it there. The Audiobahn can handle the power but its not producing any deep (powerful) sub bass.

That’s where I currently stand looking for some guidance to solve this issue.

Much regards

Philip

 

[Max Caliber]

I don't know, how many 12" holes can you cut in it? You could use the left over wood to plug to vent holes.

You must really love this box BTW.

theAnonymous1,

You haven’t answered my previous question.
If you don’t like vented enclosures and you don’t like passive radiators what would you prefer to use to get very low frequencies? I’m still waiting for your answer

Furthermore how can you explain using lots of 12” drivers to out perform a single 18” driver, and again into what kind of enclosure would you attempt to do this? Just saying you change one size of driver with many smaller drivers does not answer the question of enclosure type and the required tuning that follows.

Cheers

Philip

 

[theAnonymous1]

Sorry, I thought I made it clear I was talking about sealed enclosures with LT equalization.

The 12" driver thing was just a joke. I was suggesting it would take a lot of them to make a 12cu.ft box usable as a highly damped sealed enclosure.

Oh, and yes, sealed enclosures can and do play extremely low. It's takes more SD+XMAX+POWER to achieve this compared to BR alignments, but it's what I prefer.

You are obviously dead set on your 12cu.ft box though, so we will just pretend I'm not here anymore. Carry on.

 

[BobEllis]

If you want below 20Hz response you should either tune lower or seal the box. Operating below box tuning risks pushing the driver to its mechanical limits. Sure you driver has a stiff suspension, but you can still bottom it at 10 Hz with 500W. (using the specs that come with WinISD)

You've got a good deal of xmax and plenty of power. Why not just seal the ports and apply a Linkwitz transform or 2nd order shelving filter to boost the low end? The box may be bigger than you could get away with, but that just means you'll need less boost.

Sealed you'll pretty much run out of excursion at 15 Hz/104dB (which you could hit with your 2245H with less power and an appropriate high pass filter.) Not sure you how much more you could get out of ported since we don't seem to have published specs that are correct for the series configuration. Put two drivers in your box and gain another 3 dB. CHances are you'll run out of power if you try to LT below 15Hz at Q=.5 (Q=.7 gives flatter anechoic response but you'll run out of power sooner and in room response will likely be rising)

You'd need to rework your ports to get better extension with your current box, but you should be able to get a little higher output down to your tuning frequency. ~21" ports for 15Hz.

 

[tb46]

Measuring away:

Hi Philip,

Sooner or later you'll need to measure something, your room, your speaker(s). (I understand the JBL was fine, but that does not eliminate the room.) It sounds like your place would benefit from a multiple sub alignment procedure as per Earl Geddes:

http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html

mehlau.net > audio > multisub

Additionally, you can measure the Thiel/Small parameters with a simple multimeter, a small resistor and your computer as a signal generator. There are a lot of references on the web.

Here is Brian Steele's website:
The Subwoofer DIY Page - Measurements

and

Elliott Sound Products:
Measuring Loudspeaker Driver Parameters

Having that data will allow you to optimize the enclosure for this particular driver, and is about a necessity even with the approch outlined by BobEllis (I second that, even though for pure grunt it's hard to beat the tapped horns.)

Regards,

 

[Max Caliber]

Hi Philip,

Sooner or later you'll need to measure something, your room, your speaker(s). (I understand the JBL was fine, but that does not eliminate the room.) It sounds like your place would benefit from a multiple sub alignment procedure as per Earl Geddes:

http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html

mehlau.net > audio > multisub

Additionally, you can measure the Thiel/Small parameters with a simple multimeter, a small resistor and your computer as a signal generator. There are a lot of references on the web.

Here is Brian Steele's website:
The Subwoofer DIY Page - Measurements

and

Elliott Sound Products:
Measuring Loudspeaker Driver Parameters

Having that data will allow you to optimize the enclosure for this particular driver, and is about a necessity even with the approch outlined by BobEllis (I second that, even though for pure grunt it's hard to beat the tapped horns.)

Regards,

Thanks for the info. I'll look into it.

Regards
Philip

 

[Max Caliber]

If you want below 20Hz response you should either tune lower or seal the box. Operating below box tuning risks pushing the driver to its mechanical limits. Sure you driver has a stiff suspension, but you can still bottom it at 10 Hz with 500W. (using the specs that come with WinISD)

You've got a good deal of xmax and plenty of power. Why not just seal the ports and apply a Linkwitz transform or 2nd order shelving filter to boost the low end? The box may be bigger than you could get away with, but that just means you'll need less boost.

Sealed you'll pretty much run out of excursion at 15 Hz/104dB (which you could hit with your 2245H with less power and an appropriate high pass filter.) Not sure you how much more you could get out of ported since we don't seem to have published specs that are correct for the series configuration. Put two drivers in your box and gain another 3 dB. CHances are you'll run out of power if you try to LT below 15Hz at Q=.5 (Q=.7 gives flatter anechoic response but you'll run out of power sooner and in room response will likely be rising)

You'd need to rework your ports to get better extension with your current box, but you should be able to get a little higher output down to your tuning frequency. ~21" ports for 15Hz.

Thanks Bob

Can I ask what software you are using to get your figure?

Cheers

Philip

 

[Max Caliber]

Hi again,

A long time ago, I used to run 2 ea. sealed 2'x2'x2' w/ 4 x 10" ea., and I still couldn't hear 10Hz, but they did shake the walls .

Regards,

That's exactly what I am looking for, however my enclosure is cut for an 18' driver and 2x 4' vents.

So what can fit in it if the JBL is too fragil and the Audiobahn is unheard?

Cheers

Philip

 

[Max Caliber]

Philip:

As promised in my previous post, here is what we did for a good friend of mine. He had the same issues a) being a bassaholic 2) blowing up JBL-2245H's. The following link is the problem as expressed on a different forum:

HELP! I keep blowing my JBL 2245H subs - AVS Forum

This link to the solution - different subs:

TC Sounds PA-5000 18" came in today! - AVS Forum Archive 2

With these playing loud, the bass will actually blur your vision and crack your drywall. I have never heard anything like it, even at a concert. Sadly, that same driver is no longer available but the manufacturer website does seem to have a compelling substitute.

-Stu

Thanks Stu

I may have to follow the same route.

Regards
Philip

 

[Max Caliber]

Sorry, I thought I made it clear I was talking about sealed enclosures with LT equalization.

The 12" driver thing was just a joke. I was suggesting it would take a lot of them to make a 12cu.ft box usable as a highly damped sealed enclosure.

Oh, and yes, sealed enclosures can and do play extremely low. It's takes more SD+XMAX+POWER to achieve this compared to BR alignments, but it's what I prefer.

You are obviously dead set on your 12cu.ft box though, so we will just pretend I'm not here anymore. Carry on.

Thanks theAnonymous1

Sorry but I didn’t quite see your comment as a joke, because there was a time where I contemplated such a configuration. Note the tread where someone else suggested using multiple 10” subs to get 10Hz and that is also a possible consideration.

Check out Stu’s links to large subwoofer enclosures, now that’s what I’m looking for , seeing how I have the space and the box, for what possible reason would I want to go with something else unless it showed a serious advantage over the present configuration.

When I was asking for your preference in enclosures, I was perhaps expecting to hear of something a little more exotic such as Infinite Baffles, open dipoles, transmission lines, etc .

The whole goal of this tread was to see if anyone could help me find out why the Audiobahn AW1805Q was not performing well in a 12^3 foot box that is supposed to have been tuned to 20Hz. Unfortunately only a few comments have offered anything I can try do to remedy the problem.

Cheers

Philip

Thanks

 

[bjorno]

...When I was asking for your preference in enclosures, I was perhaps expecting to hear of something a little more exotic such as Infinite Baffles, open dipoles, transmission lines, etc ...

IMO: A piece of cake but...

The whole goal of this tread was to see if anyone could help me find out why the Audiobahn AW1805Q was not performing well in a 12^3 foot box that is supposed to have been tuned to 20Hz. Unfortunately only a few comments have offered anything I can try do to remedy the problem...

First,You have to bring order to the Audiobahn T/S mess: See the picture..

b

 

[noSmoking]

hi Max,
I just built a decware home wrecker with one 18" peavey low ryder sub, OMG! Bass,I rattled stuff off the shelves,it punches your chest, I'm pumping it with 700 watts of gianclone and it was not past 9 oclock on the volume,I'm happy,I have not tuned or tested it yet,but my pants leg shake and my chest rumbel's,lol. and I like it so far,look on this site, for THREADS peavey 18" or emmenice 21", if you just got to save the box you have get a frequency genenator, a amp, and a spectrum analyzer, and start with the ports ,get some 4" pvc sch 40 tube and cut off 20" 2 times and put them in your 4" port holes and try 10" and see what happens, chart it, maybe you need a bigger port as suggested was 21" maybe try it before you reduce size,you can put a piece of wood over a big port and adjust it as it plays,and then maybe make the box smaller and do the ports again, mine came out at 15.6 cu ft and 1 6"x8" port and 2 4" x 3/4" stock so far,BTW boxtune had it at about 10 cuft,I'll test it soon and and post it, Good luck and keep trying you will get there !!!!!!!!

 

[Max Caliber]

hi Max,
I just built a decware home wrecker with one 18" peavey low ryder sub, OMG! Bass,I rattled stuff off the shelves,it punches your chest, I'm pumping it with 700 watts of gianclone and it was not past 9 oclock on the volume,I'm happy,I have not tuned or tested it yet,but my pants leg shake and my chest rumbel's,lol.

Thx noSmoking

Congrats on your sub’s operation, it sounds very similar to what the JBL 2245 was doing for me; but that feeling is now gone since I installed the Audiobahn AW1805Q. Can you supply a little more info on this box design? I did a quick search on the web and found some interesting stuff, can you point me to the design you built? I would like to see if I could modify mine into something like yours that would help make this sub-woofer worth it, instead of just being a big heating element in my basement.

Can I ask you what the cubic volume of your enclosure is, where is it placed in your listening room, and what your the crossover frequency is?

As for test equipment, I have plenty of very high quality stuff including ultra-low distortion (Tektronix and HP) programmable frequency generators and distortion analyzers, Tektronix sweep/function generators, Tektronix 2 & 4-trace scopes with built in FFT functions, Very high precision frequency counters with sub-fractional hertz resolution driven by ultra-low tremco oscillator, hi precision digital DB meters, etc. A lot of this stuff was used when I first designed and tuned the box for the JBL with spectacular results, but nothing seems to coming together with the AW1805Q.

I could go on and on but I think this will distract from my actual problem as to what to with my basement heater?

Again THZ for the info.

Philip