Do you think this is would be a good HT performer?

[Blaser]

Hi all,

I have been using this sub for 2 years in my car. Pls check link below for details.

https://www.hci-services.com//tech_d...5GTi_rev_f.pdf

http://europe.jbl.com/car/products/p...&region=EUROPE

Indeed It is installed in a 4 Cu Ft box with a 15 " long, 6" diameter port. It is tuned 28 Hz. It is a very good performed in car (it can hits more than RS level meter can measure).

As always I like playing with my toys... I moved this sub to my HT room, but I made a small modification: I inserted a longer 5" port (approx 3.5 ft) to tune it lower. I powered it with my sony Hi Fi rated 200 WRMS *2 (10% THD). It was obvious that this was not enough power but... I am just playing.

In room response (BFD ed) was flat down to 25 Hz and began a gentle roll off below that (I suppose the box is not big enough to reinforce lower frequencies). I could have 16 Hz at - 12 db from target response. Watching matrix, It could hit up to 114-115 db. The sound is good although I have a bad amplifier, box is too small also..... as it is for car use.

Now, I am wondering if this woofer was correctly boxed (7-8 cu ft) and tuned to 18 Hz for example, what would be the result? More importantly what should be the box dimensions (volume) and port length? I need the tough guys to help me here pls!!

I have downloaded many box design programs but either they give me different results or simply there are parameters to fill that I don't understand/find!

If you think this can be a successful experience, I can buy another sub and DIY to obtain more headroom.

In a nutshell, do you think this solution can be better/stronger than an SVS Pb 12+ or HSU HOs for example? If so what box dimensions, port size, length....Amplifier do you suggest?

Thanks for helping!

Blaser

[Exocer]

Without solid stated T/S parameters from JBL we know little about the driver's capabilities. That being said, it looks like you've measured very good frequency response in your room. With a little more power and a larger box with lower tune you may be able to get a little bit more low frequency bass from this sub. Before you decide to do that it may be smarter to see if JBL can provide the necessary T/S parameters so we can throw together some simulations before you go and build another box

[Blaser]

Hi exocer! Thanks for your post!

The T/S parameters from JBL are clearly stated!! Did you check the link I posted? I think most required T/S are available. Kindly check.

Thank you.

[JorgenMan]

The only parameters I'm seeing are sensitivity, power handling, impedance, and dimensions. "Frequency Response" is 16 Hz - 1 kHz, but who knows what that really means. Contact JBL and see if they will give you T/S parameters.

[Blaser]

Ahh, Sorry I posted a wrong link.

Here is the correct one

https://www.hci-services.com//tech_d...5GTi_rev_f.pdf

and http://europe.jbl.com/car/products/p...&region=EUROPE

Thanks

[Blaser]

The Driver looks so **** GOOOOD!!!

[JorgenMan]

The driver looks good to me, but I'll leave the specific suggestions to someone with more real experience in ported boxes. Are you wanting to do a big sonosub, or do you want to keep the size down closer to 7-8 cubic feet, like you said at first? I think this should definitely outperform an SVS or Hsu.

[Blaser]

Hey JorgenMan,

Thanks for your post!! A sonosub would be rather difficult/expensive I think. I think a Sonosub is OK, but a rectangular based one.... if you see what I mean, I don't care about dimensions but at least I would try to get a small footprint.

My need is a subwoofer which would be straight linear down to 16 Hz Anechoic (I like bottom heavy bass!!), Tuned 16, very powerful below 30 Hz.... I need an in room response 6-8 db/octave gain down to 15 Hz or so. And I would like the capability to hit 120db uncompressed at 20 Hz in room. I think a hudge box would be required to reinforce the very low LF!

Maybe SteveCallas could inform us how large the box would be?

[JorgenMan]

If you want bottom-heavy bass, I'd say get a BFD or something else to equalize your response. To get anechoic response flat to 16 Hz, you're looking at 350 liters and a 31"-long, 8"-wide port. I get the impression you want something smaller than that. You just need to decide how big of a box you can handle - that will determine how low you can go.

[Blaser]

Size is not important as long as this will help in the lowest octave!

[SteveCallas]

300 liters with a 6" diameter port that is 24" long being fed with 800 watts should do what you want. Depending on your typical listening levels, you may want to build two.

[Blaser]

QUOTE=SteveCallas;26166]300 liters with a 6" diameter port that is 24" long being fed with 800 watts should do what you want. Depending on your typical listening levels, you may want to build two.[/quote]

• What would be then the FR shape, the tuning freq.?

• Does the 300 L include driver volume, port volume....? or is it a net volume?

• As this is a USD 700 driver, do you think something cheaper can do the same without compromising SQ so much?

• Is there any (known) transformer that converts 220 VAC to 12-14 V DC?

Thanks for your feedbacks!

[JorgenMan]

blaser wrote:

[*]Is there any (known) transformer that converts 220 VAC to 12-14 V DC?

There are plenty, but I'm guessing you're wanting to use it to run a car amp, right? If so, I'd say just save your money and get a pro amp. If not, I apologize for jumping the gun. If you let us know what you're needing it for (a filter, maybe?), we'd be better able to recommend one.

[JorgenMan]

blaser wrote:

• Does the 300 L include driver volume, port volume....? or is it a net volume?
• As this is a USD 700 driver, do you think something cheaper can do the same without compromising SQ so much?

The 300 liters is a net volume, so it does not include driver/port volume.

You can definitely do better for $700. Look into the RL-p 15" from SoundSplinter and the 15" TC-2000 from TC Sounds, for example. There are several threads on this forum (and others) on using these drivers in big ported sonosubs. Do some looking around, and you'll see what kind of designs people are doing.

[SteveCallas]

What would be then the FR shape, the tuning freq.?

Exactly what you asked for

Does the 300 L include driver volume, port volume....? or is it a net volume?

Net. You can do the fine math if you want, but I'd just aim for 330-340 raw.

As this is a USD 700 driver, do you think something cheaper can do the same without compromising SQ so much?

Easily. FiCar Q15, SS RLp-15, or TC 2000 15 would all work, and actually give a bit more output.

[Blaser]

JorgenMan, SteveCallas

Thank you really!

[Blaser]

SteveCallas wrote:

Exactly what you asked for


Net. You can do the fine math if you want, but I'd just aim for 330-340 raw.


Easily. FiCar Q15, SS RLp-15, or TC 2000 15 would all work, and actually give a bit more output.

Hi Steve,

What about dual SS RL-P18 each in a 565 L net enclosure volume tuned 16 Hz powered by EP-2500 in a 2000 cuft room?

Can a PVC tube be used for a sonotube and deliver similar quality as wooden boxes? If so, what would the top material be? wood? is it possible to glue wood with PVC and have acceptable results? Any guidelines to follow when doing a PVC sonotube?

Thanks in advance!

Blaser

[tjambro]

blaser wrote:

What about dual SS RL-P18 each in a 565 L net enclosure volume tuned 16 Hz powered by EP-2500 in a 2000 cuft room?

Hi Blaser, that's pretty close to what I'm doing actually. I'm shooting for dual 550L boxes with a 14.5Hz tune. Here's a link if you are interested:

http://www.hometheatershack.com/foru...llt-begun.html

-Tom A.