Recent Topics
Camry vrs Sonata
by tblt44 - 01/28/20 07:50 PM
Parasitic battery draw.
by wtd - 01/28/20 07:49 PM
AAP clearance 2020
by GMguy84 - 01/28/20 07:34 PM
2017-2019 GLA 250 4-Matic vs BMW X-1
by HangFire - 01/28/20 07:20 PM
Good news for .300blk shooters
by The_Eric - 01/28/20 06:43 PM
‘16 Lexus GS350 vs ‘16 Lexus RX350
by miden851 - 01/28/20 06:19 PM
Stone guard removal
by dawgn86 - 01/28/20 06:09 PM
Craigslist is like a petty HOA now
by eljefino - 01/28/20 05:06 PM
Shoretel PABX - any experience?
by stockrex - 01/28/20 04:44 PM
Around Australia record in the 1970's
by sanoptic - 01/28/20 03:21 PM
Oil mixing...does density matter?
by LotI - 01/28/20 02:02 PM
Uh Oh. Subaru Front Halfshaft CV Going Bad
by ARCOgraphite - 01/28/20 01:25 PM
Help choosing the right oil
by CAJ1966 - 01/28/20 12:33 PM
Which cooler line is return?
by LeakySeals - 01/28/20 11:39 AM
New Havoline ProDS 0w20 boosted Moly?
by jayjr1105 - 01/28/20 10:59 AM
Diesel fuel pump, pump synthetic 40 weight?
by H20ham - 01/28/20 10:54 AM
Review: 2019 VW Passat Wolfsburg 2.0T
by wemay - 01/28/20 10:16 AM
Group 2 mix with Group 4
by ridgerunner - 01/28/20 09:50 AM
Power Steering Fluid for 54 Chevy
by ThomasJ49 - 01/28/20 08:54 AM
Newest Members
indigo2020, Towkid, denor, Jubaxtreme, CAJ1966
70551 Registered Users
Who's Online Now
115 registered members (14Accent, 2004tdigls, Astro14, 55hambone, Avery4, adams355, 11 invisible), 3,019 guests, and 14 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics300,682
Posts5,181,045
Members70,551
Most Online4,538
Jan 20th, 2020
Donate to BITOG
Print Thread
Hop To
Page 1 of 2 1 2
Don't trust JBL "True 4-ohm Technology" !! #5315569 01/07/20 08:03 AM
Joined: Feb 2018
Posts: 302
C
cwilliamsws6 Offline OP
OP Offline
C
Joined: Feb 2018
Posts: 302
I had a JVC KD-R980BTS stereo which recently got replaced by a Kenwood eXcelon KDC-X303 to hopefully solve a problem I've been having which is that after about 20 minutes of loud listening it'll begin to distort real bad and eventually cut out entirely, so I thought the amp in the JVC was going out.

Lo and behold, the Kenwood did the same thing! I was super upset and then I remembered something:

I replaced all my door speakers with JBL GX602s about a year ago, which then come to think of it, is the time the JVC began acting up the way it had been. I looked up my JBL speakers and they're not actual 4 ohm speakers like the salesman told me.

They're 2.3 ohms but marketed as having "true 4 ohm technology," supposedly, after you account for the resistance from the car's wiring harness, up at the headunit the speakers will be seen as 4 ohms. Spoiler alert, that's a load of bull! I pulled my stereo out of the dash and metered at the harness, the highest resistance I saw was 2.6 ohms.

I pulled the JBLs out and dropped in a set of Fosgate Punch 3-ways and problem solved. They lasted over an hour at full tilt so they pass my test lol.


2007 Honda CR-V LX "The Linoleum Falcon" 210K miles
HK conv 5w20, STP blue bottle, PrimeGuard POF4610 filter.
"Bad decisions make good stories."
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315576 01/07/20 08:14 AM
Joined: Nov 2008
Posts: 15,315
S
supton Offline
Offline
S
Joined: Nov 2008
Posts: 15,315
Not an audio guy, but I'm guessing the speaker should look like 4 ohms at 20Hz through 20k, right? and who cares at DC? Are you running some sort of AC sweep to look for impedance over frequency?

As far as distortion after 20 minutes... is the amplifier getting hot by any chance?

Then again, you say you replaced the JBL's and all is fixed, so problem probably isn't amp related. Are these pure speakers? I wonder if they have some crossover component that is heating and drifting (or breaking down). Then again, I still wonder about the amps running hot with the bad speakers.


2011 Toyota Camry, base, 2.5L/6MT, 200k, hers
2010 Toyota Tundra DC, 4.6L/6AT, 157k, ours
1999 Toyota Camry LE, 2.2L/4AT, 221k, his
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315583 01/07/20 08:20 AM
Joined: Aug 2017
Posts: 1,201
sloinker Offline
Offline
Joined: Aug 2017
Posts: 1,201
Impedance versus resistance. In home audio you need a lot of amplifier to run speakers that have low impedance at certain frequencies. I still have a couple amplifiers that weigh in near 50 pounds and they aren't the heaviest out there by a long shot. Of course there may be an issue with the JBL's or you just might not have enough real amplifier. I'm not counting the class D's that drive the sub(s).


'16 Tiguan TSI Vaico 5W40
'15 VW Golf TDI Ravenol VMP 5W30
'15 VW Golf Sportwagen TDI VMP 5W30
'14 Dodge Grand Caravan 3.6 Red Line Blue Label 5W20
'64 Plymouth Fury440 Red Line Blue Label 10W40
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315585 01/07/20 08:22 AM
Joined: Feb 2018
Posts: 302
C
cwilliamsws6 Offline OP
OP Offline
C
Joined: Feb 2018
Posts: 302
The JBLs had no crossover that I know of, they were coaxials


2007 Honda CR-V LX "The Linoleum Falcon" 210K miles
HK conv 5w20, STP blue bottle, PrimeGuard POF4610 filter.
"Bad decisions make good stories."
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315607 01/07/20 08:49 AM
Joined: May 2009
Posts: 14,216
A
ARCOgraphite Offline
Offline
A
Joined: May 2009
Posts: 14,216
You don't test speaker impedance with DC. But if the VC r measures well below 3 ohms DC, it's not a 4 ohm speaker

The speaker impedance will dip pretty low above the bass resonance point to near 1/2 its "average" rating
then level off in the upper bass /lower midrange at the near Nominal rating.

Here is a plot of an 8 ohm nominal speaker in a ported enclosue ( note the camel-hump shape of the curve in the bass)

Note the approx 3-1/2 ohm measurement in the lower midrange

[Linked Image]

Last edited by ARCOgraphite; 01/07/20 08:52 AM.

2019 VW Jetta S 6MT OCI#2 7378mi-MOTUL Specific VW508.00+VW Service Filter; '17 Subaru Crosstrek CVT OC#8 60864mi-Subaru Idemitsu 0W20 + SOA Filter
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315640 01/07/20 09:21 AM
Joined: Mar 2004
Posts: 23,697
D
Donald Online Content
Online Content
D
Joined: Mar 2004
Posts: 23,697
Maybe don't listen so loud.

Comes from an old guy now with tinnitus (me).


2015 Ford F-250 w/Powerstroke
2016 Subaru Crosstrek CVT (wife's)
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315688 01/07/20 10:19 AM
Joined: Apr 2012
Posts: 2,982
B
buck91 Offline
Offline
B
Joined: Apr 2012
Posts: 2,982
Interesting. I have some very nice JBL 6x8 from a few years back that sound amazing. Finally put a HU in which is worth a dang and they are just fantastic. Sorry to hear the new models aren't up to snuff.


2011 F150 4x4 5.0L
1996 Mustang GT 5spd/ragtop
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315718 01/07/20 10:57 AM
Joined: Jan 2016
Posts: 1,209
Duffyjr Offline
Offline
Joined: Jan 2016
Posts: 1,209
The speakers were asking to much from the amp, I think they call that clipping. Glad you fixed it with new speakers.

OP how do they sound at lower volume, the Rockford's were on my list but went with Infinity instead.


89 GMC Sierra Advanced 5w30/51036 Wix
08 Lucerne CX Advanced 5w30/1040 Gold
18 Toro Super Recycler T5 10w30
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315753 01/07/20 11:34 AM
Joined: Feb 2018
Posts: 302
C
cwilliamsws6 Offline OP
OP Offline
C
Joined: Feb 2018
Posts: 302
Paired with the Kenwood eXcelon headunit, they sound absolutely beautiful. So crisp and clear it's almost unreal, not too "tinny" sounding, it's nice, full and rounded. I have the HPF set at 120hz so I'm basically only using the tweeter portion anyhow, my subs in the trunk take care of the lows.


2007 Honda CR-V LX "The Linoleum Falcon" 210K miles
HK conv 5w20, STP blue bottle, PrimeGuard POF4610 filter.
"Bad decisions make good stories."
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5315798 01/07/20 12:47 PM
Joined: Jan 2004
Posts: 6,301
N
nthach Offline
Offline
N
Joined: Jan 2004
Posts: 6,301
Harman pulled the same stunt with the JBL sound systems offered as an option in Toyotas - except they use the JBL amp and low impedance speakers. The amp has a DSP and uses digital trickery for fade/balance, the head unit/HMI simply pipes in analog stereo and IEBus commands to the amp.

Re: Don't trust JBL "True 4-ohm Technology" !! [Re: ARCOgraphite] #5315814 01/07/20 01:10 PM
Joined: Jun 2012
Posts: 768
R
redbone3 Offline
Offline
R
Joined: Jun 2012
Posts: 768
Originally Posted by ARCOgraphite
You don't test speaker impedance with DC. But if the VC r measures well below 3 ohms DC, it's not a 4 ohm speaker

The speaker impedance will dip pretty low above the bass resonance point to near 1/2 its "average" rating
then level off in the upper bass /lower midrange at the near Nominal rating.

Here is a plot of an 8 ohm nominal speaker in a ported enclosue ( note the camel-hump shape of the curve in the bass)

Note the approx 3-1/2 ohm measurement in the lower midrange

[Linked Image]



A speaker presents a mostly inductive load to the amplifier. Impedance varies with frequency. It's impossible to get an even impedance over any significant frequency range.

Last edited by redbone3; 01/07/20 01:10 PM.

2014 Passat Wolfsburg, 1995 Miata.
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5316044 01/07/20 06:18 PM
Joined: Sep 2002
Posts: 3,881
Propflux01 Offline
Offline
Joined: Sep 2002
Posts: 3,881
Used to be speaker manufacturers would advertise their speakers as "nominal impedance" when referring to their established number (2, 4, 8, 16 ohm, etc.).

Nominal: , being, or relating to a designated or theoretical size that may vary from the actual


2014 Hyundai Elantra
2014 Hyundai Elantra GT
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5316204 01/07/20 09:39 PM
Joined: Apr 2008
Posts: 41,300
O
OVERKILL Offline
Offline
O
Joined: Apr 2008
Posts: 41,300
Originally Posted by cwilliamsws6
I had a JVC KD-R980BTS stereo which recently got replaced by a Kenwood eXcelon KDC-X303 to hopefully solve a problem I've been having which is that after about 20 minutes of loud listening it'll begin to distort real bad and eventually cut out entirely, so I thought the amp in the JVC was going out.

Lo and behold, the Kenwood did the same thing! I was super upset and then I remembered something:

I replaced all my door speakers with JBL GX602s about a year ago, which then come to think of it, is the time the JVC began acting up the way it had been. I looked up my JBL speakers and they're not actual 4 ohm speakers like the salesman told me.

They're 2.3 ohms but marketed as having "true 4 ohm technology," supposedly, after you account for the resistance from the car's wiring harness, up at the headunit the speakers will be seen as 4 ohms. Spoiler alert, that's a load of bull! I pulled my stereo out of the dash and metered at the harness, the highest resistance I saw was 2.6 ohms.

I pulled the JBLs out and dropped in a set of Fosgate Punch 3-ways and problem solved. They lasted over an hour at full tilt so they pass my test lol.


So I just quickly googled these speakers and found:

[Linked Image]

The manual, AVAILABLE HERE confirms this.

So yeah, driving a 2.3ohm load with an amp designed for 4ohms, it is not surprising that you had problems.


2019 RAM 1500 Sport - Mobil 1 EP 0w-20, FRAM Ultra
2020 Grand Cherokee SRT - Ravenol SSL 0w-40, FRAM Ultra
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5316429 01/08/20 07:26 AM
Joined: Feb 2018
Posts: 302
C
cwilliamsws6 Offline OP
OP Offline
C
Joined: Feb 2018
Posts: 302
See that right there is why I am as upset about it as I am.

Depending where you look you'll find the speakers I had listed as being 2.3 ohm, 3 ohm, or 4 ohm. It's confusing and I doubt I'm not the only one who has had this issue because of it.


2007 Honda CR-V LX "The Linoleum Falcon" 210K miles
HK conv 5w20, STP blue bottle, PrimeGuard POF4610 filter.
"Bad decisions make good stories."
Re: Don't trust JBL "True 4-ohm Technology" !! [Re: cwilliamsws6] #5316503 01/08/20 08:16 AM
Joined: Apr 2008
Posts: 41,300
O
OVERKILL Offline
Offline
O
Joined: Apr 2008
Posts: 41,300
Originally Posted by cwilliamsws6
See that right there is why I am as upset about it as I am.

Depending where you look you'll find the speakers I had listed as being 2.3 ohm, 3 ohm, or 4 ohm. It's confusing and I doubt I'm not the only one who has had this issue because of it.


Yup, the manual lists them as having 3ohm coils with the nominal impedance as 2.3ohms, per the above chart. I could definitely see them causing an issue with an amp that's not capable of comfortably driving loads below 4ohms.


2019 RAM 1500 Sport - Mobil 1 EP 0w-20, FRAM Ultra
2020 Grand Cherokee SRT - Ravenol SSL 0w-40, FRAM Ultra
Page 1 of 2 1 2
Previous Thread
Index
Next Thread

BOB IS THE OIL GUY® Powered by UBB.threads™