AVS Forum | Home Theater Discussions And Reviews (https://www.avsforum.com/forum/)
-   DIY Speakers and Subs (https://www.avsforum.com/forum/155-diy-speakers-subs/)
-   -   4645C Clone in Aus. Figures not working out? (https://www.avsforum.com/forum/155-diy-speakers-subs/2383762-4645c-clone-aus-figures-not-working-out.html)

AudyoVidyo 03-29-2016 07:45 PM

4645C Clone in Aus.
 
Hey guys,
I am currently embarking into the world of JBL Pro Cinema speakers. Of course everything costs more when you live on the biggest island in the world...

So I bought a used 2242HPL from an ebay seller in the US and it is on it's way to me currently. I will be building a 4645C clone with it. Works out about a quarter of the price of buying a full 4645C here in Australia. (And eliminates an 8 week lead time too).

My question relates to the 4645C box. I put the driver parameters into WinISD and ran the sim. However the 225L net box volume and port dimensions don't really work out to the 25Hz port tuning as stated in the PDF: http://www.jblpro.com/pub/cinema/4645c.pdf

I input the 225L (8cu ft) and a 8" port diameter stated in the PDF, and it spits out a 54.13cm (21.31") port length? When in this thread: http://www.diyaudio.com/forums/subwo...l-4645c-2.html the guy actually measured the port in the 4645C and it is 7.25" to 7.5" internal diameter only 12.5" long. This works out to about a 28Hz tuning? Am I missing something? Or is the 4645C port not actually tuned to 25Hz?

LTD02 03-29-2016 07:54 PM

winisd can overstate the tuning frequency by a bit. known issue.


josh measured that cab to have a tuning frequency of 26hz or so, as that is about where the impedance is at a minimum.


if using one sub, ~25hz is probably a decent tuning.
if using two subs, ~22hz may be a little better.
if using four subs, ~18-20hz may be a little better.


just a tradeoff in excursion constrained max output and extension, so it kind of depends on personal playback preference.

AudyoVidyo 03-29-2016 08:30 PM

Thanks LTD. If that is a known issue then it makes it a little hard to get it right when designing any sub doesn't it. *sigh*

I will just have one to start with so will go with the 25Hz tuning. I will go with the manufacturers dimensions then and hope that it is right.

I have two Dayton HO18 martycubes at the moment. I know the JBL won't go as low, but it has the punchiness that the Daytons seem to lack. I am willing to trade extension for punch.

I will document the build here too.

chrapladm 03-29-2016 09:45 PM

Where are you located?

LTD02 03-29-2016 10:03 PM

Quote:

Originally Posted by AudyoVidyo (Post 42826202)
Thanks LTD. If that is a known issue then it makes it a little hard to get it right when designing any sub doesn't it. *sigh*

I will just have one to start with so will go with the 25Hz tuning. I will go with the manufacturers dimensions then and hope that it is right.

I have two Dayton HO18 martycubes at the moment. I know the JBL won't go as low, but it has the punchiness that the Daytons seem to lack. I am willing to trade extension for punch.

I will document the build here too.

yeah, that's right, but at the end of the day, 1-2hz isn't going to make or break most subs.


the manufact. dimensions should give you about a 26hz tune or so.
http://www.data-bass.com/data?page=system&id=68
I thought he posted the impedance sweep, but now I can't find it. :-)


the jbl has a rising response, so some of that extra punch is frequency response related. some is sensitivity related.


are you planning on a protective high pass for the 4645c clone?

Tip24/96 03-30-2016 06:02 AM

Quote:

Originally Posted by LTD02 (Post 42827570)
yeah, that's right, but at the end of the day, 1-2hz isn't going to make or break most subs.


the manufact. dimensions should give you about a 26hz tune or so.
http://www.data-bass.com/data?page=system&id=68
I thought he posted the impedance sweep, but now I can't find it. :-)


the jbl has a rising response, so some of that extra punch is frequency response related. some is sensitivity related.


are you planning on a protective high pass for the 4645c clone?

I have a couple of those drivers that I am planning to build enclosures for sometime in the next 6 weeks or so. What would you suggest as the optimal vented enclosure volume, tuning frequency and port length for a single driver enclosure used to support the mid bass frequencies? Just like the OP, I had several ho18's in full sized Marty enclosures.

AudyoVidyo 03-30-2016 04:26 PM

Quote:

Originally Posted by chrapladm (Post 42827314)
Where are you located?

Ipswich QLD mate.

Quote:

Originally Posted by LTD02 (Post 42827570)
yeah, that's right, but at the end of the day, 1-2hz isn't going to make or break most subs.


the manufact. dimensions should give you about a 26hz tune or so.
http://www.data-bass.com/data?page=system&id=68
I thought he posted the impedance sweep, but now I can't find it. :-)


the jbl has a rising response, so some of that extra punch is frequency response related. some is sensitivity related.


are you planning on a protective high pass for the 4645c clone?

That's true. Yes I have a minidsp which will be doing that job for it. I'd never use a ported sub without a hpf.

I will give it a go and might even do a REW sweep once it is all built to check the tune.

LTD02 03-30-2016 05:15 PM

Quote:

Originally Posted by Tip24/96 (Post 42831042)
I have a couple of those drivers that I am planning to build enclosures for sometime in the next 6 weeks or so. What would you suggest as the optimal vented enclosure volume, tuning frequency and port length for a single driver enclosure used to support the mid bass frequencies? Just like the OP, I had several ho18's in full sized Marty enclosures.

do you still have the ho18 subs or are you planning to replace them with the 2242 subs? I'd think your midbass would be covered by your mains.

chrapladm 03-31-2016 04:04 AM

Quote:

Originally Posted by AudyoVidyo (Post 42849434)
Ipswich QLD mate.

Wishful thinking. Hoping to eventually find some others around my area someday.

mantha3 03-31-2016 07:17 AM

Here is my build with the dimensions above.

http://www.diyaudio.com/forums/subwo...jbl-4645c.html

This has been unreal and still love it after a few years.

mantha3 03-31-2016 07:20 AM

PS - This sub works wonders with music... Bass drums... etc...

NWCgrad 03-31-2016 07:39 AM

I just added dual 4645B's to my HT, they were exactly what I was looking for (seamless integration with mains for music reproduction).

They don't dig near as deep as my sealed sub did, but they are an improvement in areas most important to me. Bass guitar reproduction is phenomenal.

Thanks @mantha3 for the build thread that planted the seed.

mantha3 03-31-2016 08:36 AM

Quote:

Originally Posted by NWCgrad (Post 42862946)
I just added dual 4645B's to my HT, they were exactly what I was looking for (seamless integration with mains for music reproduction).

They don't dig near as deep as my sealed sub did, but they are an improvement in areas most important to me. Bass guitar reproduction is phenomenal.

Thanks @mantha3 for the build thread that planted the seed.

Nice!

I run a Morel 12" sub along with the 4645B. I had built this Morel sub prior to the JBO 4645... Rounds out some of the bottom.

AudyoVidyo 03-31-2016 07:54 PM

Quote:

Originally Posted by mantha3 (Post 42862106)
Here is my build with the dimensions above.

http://www.diyaudio.com/forums/subwo...jbl-4645c.html

This has been unreal and still love it after a few years.

Good stuff mate. The rep these drivers has never ceases to amaze me.

AudyoVidyo 03-31-2016 08:10 PM

On a side note, my mains were planned to be JBL 3677's. However that is getting less and less likely as the cheapest price per unit I was able to find locally was $1400ea. Now that is not horrific or anything. It is just a smidge out of my possible price range.

However, this is the DIY forum. :) I have been trying to find some second hand drivers, horns and crossovers from the US and building some myself. This seems to be the only option that may be more reasonably priced for me. However sourcing all of the components at once is a nightmare! (If someone here wanted to pull apart some used 3677's and ship the components to me that would amazing!)

Alternatively, I am going to be auditioning these this afternoon: http://www.krix.com.au/fanatix.html. Krix is a local company that supplies commercial cinemas around the world. My only concern (without hearing them) is that they utilize a 10" driver (compared to the 15" of the 3677), and a fabric dome tweeter?? with waveguide. (My concern was sending a large amount of power to a dome tweeter).

I asked why not a compression driver like the JBL's and Krix's commercial cinema range, and they told me this:
- Often the metal dome (titanium) tweeters are actually not as sensitive and that reduces the effective power handling.
- Power handling is more related to the voice coil dimension (not the dome) and also if it is ferro fluid cooled.
- Our tweeters have both high sensitivity and are ferro fluid cooled. The waveguide also gives more power handling due to the improved sensitivity.

They are a great company and have a strong reputation so I don't want to pre-judge. I will let you know my thoughts after the audition... ;)

chrapladm 03-31-2016 08:33 PM

They do sell their commercial cinema stuff if you have the room. I live 5mins away from Krix and tend to listen to most of the commercial stuff. You can always build a fusion 15v2 or similar from DIYsoundgroup also.

AudyoVidyo 03-31-2016 08:41 PM

Quote:

Originally Posted by chrapladm (Post 42882338)
They do sell their commercial cinema stuff if you have the room. I live 5mins away from Krix and tend to listen to most of the commercial stuff. You can always build a fusion 15v2 or similar from DIYsoundgroup also.

Oh ok. Jealous...

Midbass is the thing that really gets me so I'll be interested to see what the 10" drivers can offer. I haven't heard the 3677's but their reputation for midbass impact is hight. I'll try and get a quote on the Krix Pix as well. (Seems to be their base cinema speaker using a 15" woofer & CD?) DIYSG don't ship internationally they said?

chrapladm 03-31-2016 09:52 PM

Not hard to order parts from Erich and then have it shipped to your door. Not sure why he said they wont ship to OZ. I have bought from him before and he shipped to me just fine.

AudyoVidyo 04-01-2016 02:31 AM

Ah ok. I might try him again.

Anyway! I am now back from the Fanatix demo. It was set up in a reasonably treated demo room running through a NAD AV receiver with about 80W/channel. Let me first say that they are obviously designed to bridge the gap between typical hi-fi speakers being used for HT - and true cinema grade speakers. That part is obvious in retaining the fabric dome tweeter of a typical hifi speaker.

To be honest... They sounded exactly like what you would imagine a speaker as I have just described would sound like. The tweeter makes for easy listening and is non-fatiguing for sure. However it seems to be slightly outpaced by the 10" driver in the unit which I feel was much more sensitive driver just by listening to it. Unfortunately the 10" driver didn't deliver the IMPACT that I am looking for in my next LCR setup, nor the 'gravitos' in the vocals I love so they are not for me. However they are a well-placed speaker with a specific market and I think they are appropriate in their own right.

Looks like 15 inch + compression driver and no less for me now...

...so now to find the right solution...

Tip24/96 04-01-2016 07:24 AM

Why not build a Fusion 15 with an AE15 woofer or similar high end pro style woofer?

LTD02 04-01-2016 09:18 AM

1 Attachment(s)
here is the 4722n response (orange) and the deltalite ii 2515 driver in 6 cubic feet tuned to 45hz (green).


that should provide the midbass response that you are looking for. with the 4722n you get a better horn, c.d., and two drivers (obviously) which is going to provide more sensitivity and more output. BUT, if that is not an option, the fusion 15 in a proper box should do you well. sensitivity is close, directivity is good, and output should be up in the 120db ballpark (where the drivers will be running out of excursion).


https://www.avsforum.com/forum/attach...1&d=1459527161

AudyoVidyo 04-01-2016 03:11 PM

Thanks ltd. What would I do for a crossover do you think?

LTD02 04-02-2016 07:22 AM

Quote:

Originally Posted by AudyoVidyo (Post 42902250)
Thanks ltd. What would I do for a crossover do you think?


the stock crossover would work just fine with no modification. matt (mtg90) did a very nice job with it.


the deltalite ii 2515 is the woofer used in the fusion 15 speaker. I was simply suggesting a much larger cab to give a response with no eq that would be almost identical to the 4722n bass frequency response.

AudyoVidyo 04-04-2016 04:07 AM

Thanks ltd. After considering all options, I have just placed an order for 3x 3677's and 4x 8320 for a 7.1 setup. Along with the sub, this should do me for a good while. I am really looking forward to the punch of such a setup. However they say it can be up to 8 weeks before I get it! Oh well. Good things come to those who wait.

However! I have just been sidetracked with the thought of retaining the current Martycubes with my Dayton 18HO's in them in order to play from about 30Hz and down where the JBL2242H can out of puff... Is is possible to use my MiniDSP 2x4 to do a 'crossover' at 30Hz to the two Dayton's?

My subwoofer setup for reference:
AV Receiver > Cleanbox Pro II > MiniDSP 2x4 (Output 1) > Behringer EP4000 > One Martycube per channel (behind screen wall)
MiniDSP (Output 2) > Behringer iNuke 1000DSP > 2xInfinity 1260W (in a single 25Hz ported box nearfield)

Any suggestions on how I can modify this setup to continue to still get sub-30Hz content? I am open to the thought of build one or two full Marty's for an even bigger improvement in depth. However I have a feeling that the two very different types of subwoofer systems (JBL & Dayton HO) may not play very nicely together. Am I wrong?

NWCgrad 04-04-2016 05:06 AM

Just use two of the miniDSP outputs for the JBL subs and the remaining two for the Marty-subs. The miniDSP has all the tools necessary to optimize such a system. I am running two JBL4645B's with two Eminence Lab-12 diy subs with no issues.

AudyoVidyo 04-04-2016 05:35 AM

Quote:

Originally Posted by NWCgrad (Post 42961290)
Just use two of the miniDSP outputs for the JBL subs and the remaining two for the Marty-subs. The miniDSP has all the tools necessary to optimize such a system. I am running two JBL4645B's with two Eminence Lab-12 diy subs with no issues.

Nice. I just looked at your setup. Man those 4645B's really set it off. I guess I can only try it out.

AudyoVidyo 04-06-2016 10:52 PM

Ok well, I've pulled the trigger. Despite the cringe factor of the price, I have just ordered 3x3677's and 4x8320's for a full JBL 7.1 pro setup. Phew! Just a little bit exciting... JUST A LITTLE! :D

Now my 2242HPL is in the country and all going well should be here in the next few days. I have to get the enclosure built asap for it.

So looking around, I have hit my second snag in that I can't find a 185mm diameter pipe (or similar) anywhere to use as a port! I have easy access to 150mm PVC pipe which I think I will just have to end up using. So to work out the port length, I am a little lost. Since LTD02 mentioned that WinISD is not all that accurate for port length in that it overestimates a bit, I am not really sure what to do.

I tried this calculator but it spits out a different result again.

My parameters are:
225L (7.95cu ft) net box volume
25Hz desired port tuning
150mm (5.9") internal port diameter

WinISD tells me that I need a 26.6cm (10.47") port length.
This calculator (http://www.calculatoredge.com/new/ventlength.htm#length) tells me that I need a 37.7cm (14.84") port length.
What the?

Can anyone help me out with this?

chrapladm 04-06-2016 11:04 PM

Using a 5.9" area I calculate a 10.46" length is needed for a 25hz tune in 225L.

AudyoVidyo 04-06-2016 11:27 PM

Quote:

Originally Posted by chrapladm (Post 43049002)
Using a 5.9" area I calculate a 10.46" length is needed for a 25hz tune in 225L.

What did you use to calculate that chrapladm? And do you mean 5.9" diameter or area?

EDIT: I just tried this calculator (http://www.carstereo.com/help/Articles.cfm?id=31) and it spat out a 10.51" port length.
And this one (http://www.linearteam.dk/default.asp...ventcalculator) and it gave me the same 10.51" port length. So I guess the consensus is around the 10.5" mark?

AudyoVidyo 04-06-2016 11:54 PM

Checking the air velocity in WinISD with the 5.9" (150mm) diameter port.

With a HPF 4thO BW at 20hz, no EQ and keeping keeping power down so cone excursion stays under the 9mm Xmax (allows me 300W max before going over Xmax at 19Hz), I am getting a max velocity of 23.4 m/s peak.

Not ideal, especially after I add 3dB boost @ 25Hz as planned and lower power to 200W (to limit it to under Xmax) I am getting a 26.6m/s peak.

Thoughts?


All times are GMT -7. The time now is 10:43 PM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
vBulletin Security provided by vBSecurity (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.