Jump to content


Premium Members
  • Content count

  • Joined

  • Last visited

  • Days Won

  • Feedback

  • Country

    United States

keep_hope_alive last won the day on October 12

keep_hope_alive had the most liked content!

Community Reputation

1,620 Excellent

1 Follower

About keep_hope_alive

  • Rank
    Acoustics Engineer
  • Birthday 08/21/1978


  • About me
    love audio in all forms, circuit designing, electronics in general.
  • Name
  • Location
    Quad Cities, IL
  • Occupation
    Acoustics Engineer / Electrical Engineer - consultant specification design engineer - i control noise and room acoustics and design electrical power systems.
  • Interests
    move electrons
  • Audio System Setup
    Alpine DVA-9861, Alpine PXA-H800, Audison LRx5.1k, Hertz MLK-165, Hertz ML3000

Recent Profile Visitors

2,353 profile views
  1. Hey KHA, 

    I imagine its pretty rare to find someone with your credentials who has a very similar car and the same amp, so I hope you don't mind me bugging you again.  I have an upgrade install coming up in two days and before I do it, I would love to get your opinion. This ended up being quite a bit longer than I anticipated so I'd be happy to send you a gift certificate to a restaurant or something for helping me make these choices.  You can PM me.

    I attached drawings of the current and proposed setups to try to make it more clear.  I'm an orthodontist not an engineer so I hope they make sense.

    My current setup is

    Front Stage: Focal 165 KRX2 components plus

    Subwoofer: JL 12W6 subwoofer

    Amp: Vx1000/5 off the factory EX-L touchscreen unit with the signal tapped after the factory amp running into a JL Fix.  I am not getting enough volume to make me happy although the SQ is excellent.  Currently the passive crossovers are being used, biamped (jumpers connecting the W and Tw removed so that each channel can be individually time-aligned).  

    I feel like I should be able to get more volume out of just the front stage and the sub... Focal says these speakers are "extreme power handling" but they don't get that loud with the current setup.  We got 107 dB using an iphone's internal mic and Audiocontrol's app.  Older tracks from the 70s and 80s max out in the 95 dB range.  I am planning on adding rear speakers because I don't want to decide I need them later and then have to pay additional to have it re-tuned.

    Speakers are two ohms so bridging channels is out.  They call for 120W RMS and I am only feeding them 90-100W.  When I designed the system I was thinking that 100W to the Woofer and 100W to the tweeter was like giving them 200W.  I guess I was wrong and I am learning this as I go.

    I would like to see what you think about my proposed setup  It's a little different in terms of normal configurations.

    1. Tap the signal ahead of the amp as you suggested.  Ditch the JL Fix-82 for full refund.  (I asked for this originally but I don't think the installers knew how to handle balanced signals and they thought it was non-variable.  I really appreciate your input, the wiring diagrams etc.)

    2. Add a Vx600/2 and power the woofers in the front doors.  The speakers are rated 120W/240W and the 600/2 would feed them 225W/300W at 2 Ohms at 12.5V/14.4V.  Thinking is that the tweeters are getting plenty of power off the Vx1000 but the woofers could use a little more juice. 

    3. Run fully active in the front with 90-100W from the Vx1000 to each tweeter and 225-300W to each woofer from the Vx600/2.  

    4. Add rear coaxial K2s and run channels 3 and 4 from the Vx1000 to them.

    A couple of questions:

    1. What kind of SPL should I expect to get in an Accord Coupe with a front stage and a sub?  I don't really want to make all these changes if I don't have to add rear speakers and what I have could be improved by changing to say the HD 600/4 for the front stage and XD 600/1 for the sub and then adding a separate DSP.  My fear is that if I do that and its still not enough volume I will be switching amps again and incurring additional tuning and installation costs.

    2. How do you feel about the SPL I am getting?  Should I just suck it up adn add rears or would I be able to get a jump from a combo of (A. tapping the 3V from the radio, B. going fully active, and C. adding power to the current speakers)

    2. How would you connect the factory signal into the Vxi amps?  Do I need all 5 wires (FL FR RR RL SUB) or should I just connect to FR and FL to get a full range signal.  SInce I am running two amps should I run the signal to each of them using the rear outputs?  Are the rear outputs full range?  

    2. Alternatively, would you connect all five wires to the VX1000/5 and connect the Vx600/2 via optical?

    3. Anything jump out at you that you don't like?  I know it seems a little overkill but I couldn't figure another 2 amp setup that gave me: 1. 150W+ to the woofers, 2. allowed me to run fully active in the front 3. power rears 4. 600W to the sub. 

    4. I was told advised not to go with the Audiocontrol 6.1200 or the Focal 900/6 with a Mono for the sub and a separate DSP.  The AC would have given me 150W/6 allowing me to power all the front and rear speakers and then add a mono.  There would have been some cost savings there, but the lead installer/manager said I would take a hit in quality according to some of his colleagues he polled.  The JL Vx 600/6 didn't give me anymore power to the front stage.  I have ordered the 600/2 but I could always put off the install and reschedule if you think I need to make some changes.   Thank you!  And again, I know this was stupid long, so I'm happy to buy you a few drinks at a restaurant near you





  2. keep_hope_alive

    2014 Accord Sport SQ Build keep_hope_alive

    Hi! I'll answer the second question first. Yes, the signal is variable so you can control the volume with the HU. Handy, eh! Why did I do all this work? It's a good question. The answer is experimentation for the Accord community. I felt it was worth running the VXi through it's paces, trying several configurations, to determine if this is an option for most of the 9th Gen Accord owners out there. I mod one Accord forum and participate in another and there were a lot of questions on how to upgrade the sound system. If I can make a simple amp install work for powering speakers, subs, and correcting for EQ then that's a real tidy solution. Another reason is that my participating in the Beta Test group for the VXi amplifiers (we're still testing aspects and updates) meant I wanted to keep seeing how changes behave and benefit the install. Another reason I moved back to the non-touchscreen is because the touchscreen has external components for FM, ANC, Amplifier, and HFL/BT; which I didn't have and am having a hard time finding salvage versions of the HFL/BT unit with a cut off harness (since I need to extend the wiring). I can live without FM but losing BT/HFL is annoying. The non-touchscreen has most of the components built-in (only ANC is external). Also, the 8" iMid screen has a better image and better resolution with the non-touchscreen. This may be due to the fact my touchscreen is from a 2015 Hybrid and I transplanted it in a 2014 Sport. I can swap back at any time - and i'm tempted to given how good the touchscreen HU sounds.
  3. keep_hope_alive

    Hearing distortion at low levels 6.5"

    Another reason could be a crossover in the head unit settings or in the factory amp (if you're still running through a factory amp - which most GM vehicles have)
  4. keep_hope_alive

    Hearing distortion at low levels 6.5"

    I could spend more time on this but most of the time aftermarket speakers have weak bass because they aren't sealed to the door panel. This lack of a seal is like asking a speaker to play bass without an enclosure. The door panel is the speaker enclosure and that seal is VITAL for any bass response. Look into the speaker grill with a flashlight. If you see the woofer moving a lot but don't hear a lot of bass - you need to gasket it. Luckily, that cost is only $4 because it is achieved with closed cell weatherstripping foam you can get at any hardware store. Just be careful to not put any on the actual surround, but instead around it on the basket. The thickness you need depends on the gap between the speaker and the door panel - verify/measure this. And if you put the door panel on then take it off again you should see an indent in the foam - proving you made a tight seal.
  5. keep_hope_alive

    Sensitivity and Watt's Question

    Hi, I know you said 22W but i should have clarified that you can expect the first 5W to be usable, listenable. Beyond 5W distortion becomes audible and at 10W it will sound poor and at 22W it will be un-listenable and likely not possible. This relates to how these amplifier IC's are rated. Note that the amplifier IC itself is contained on a single chip the size of a quarter and it does all of the amplification for all 4 channels. This amplification is the result of the outputs being bridged (so think of it as an 8 channel amp bridged to 4 channels). But the IC has power leads the size of a thin lead which could in no way handle 88W of output power (since input power is output power + efficiency losses (heat). Instead, a manufacturer can rate an amp 22Wx4 if only one channel can produce 22W for one second. It is misleading, I know, but that's how the industry has been for years (home receivers are notorious for this - note the UL Listed max power draw of a receiver - such as 100Wx7 with a max draw of only 325W). Typically, you can assume about 25% of an IC amplifier chip being usable. Long story short, expect you'll only want to listen to 5W per channel of a head unit. JBL, Polk, Hertz, JL Audio, Alpine - all have viable options in those sizes - even if they are entry-level models. My personal favorite for coaxial 6.5 and 6x9 combos is the Hertz High Energy (now the Mille Pro). But those come at a steep price. Keep in mind you'll want to consider wiring up front components so the tweeters are pointed at your face - that will greatly improve sensitivity since door speakers are pointed at your ankles.
  6. keep_hope_alive

    SQ Subwoofers

    There are many factors that determine how much "SQ" you can get out of a sub, and sub selection is lower on the list of important items. The enclosure and sub combo will determine the low end extension that can be produced and the sub/enclosure placement in the vehicle determine what you actually hear. The Sundown SA-12 can be an excellent budget SQ sub and one I may personally run in the near future (replacing an expensive sub). If you'd like to now more about why I mention Sundown, there is a good interview with the owner here where he discusses his testing procedures and what the latest version has to offer: Dayton Audio also makes good products for the price point. That said, JL Audio does an excellent job and their products are highly recommended. The idea that you need a sealed enclosure for SQ is a misnomer. Ported enclosures can improve/extend frequency response and increase overall enclosure efficiency. Both of which can help with SQ goals. But the placement of the enclosure determines what cancellation you will get. Consider wavelengths of interest and how the rear of the vehicle produces a reflection that can cancel the direct path. Certainly, take time to play around with placement, and don't be surprised if rear corner loading (facing into the corner) sounds the best. One good way to test is to listen to tracks with bass that "walks the scale" - meaning it varies from high to low frequencies while you listen for consistent output. If some notes are louder than others (and conversely some are quieter) then you may be hearing phase interference (cancellation or addition).
  7. keep_hope_alive

    Sensitivity and Watt's Question

    Hi! Actually, output goes up by 3dB for every doubling of power. https://jlaudio.zendesk.com/hc/en-us/articles/217201737-Doubling-Power-vs-Doubling-Output Sensitivity is one factor that you can use to evaluate speaker choices, but it's not the only factor. Some aspects of speaker design that improve sensitivity may sound worse. One difference between a dust cap and a phase plug is that the dust cap adds output (increases the sensitivity rating) but usually does so at the sacrifice of frequency response in the upper octaves. In general, your thinking is correct that having a speaker system with higher sensitivity will be louder on a head unit. You can only plan on 5W being usable out of a head unit, all channels driven. Beyond that distortion becomes audible, and quickly. You should still be able to achieve a 93-95dBA output level which is plenty for HU power. So, assume you find a speaker system with 90dB 1W & 1M and you give it 4 clean watts of power - you can expect 96dB 4W @ 1M. In a car, you sit about 1 meter away from a speaker and about 2 meters from the rest. Overall output would be the logarithmic sum of all four speakers, getting you close to 100dBA of possible output - theoretically assuming no cancellation occurring. My recommendation for piecing a system together is to buy what you want at the end, in steps. Sacrificing now and getting something cheaper isn't saving money if you plan on buying the better version later. Saving up for the good item is worth the wait (or finding it used for a fraction of the cost).
  8. keep_hope_alive

    New radio overheating

    some line output converters include a circuit to sense when an audio signal is present and turn the amplifier on. That would be a good choice. David Navone Engineering has one, Audio Control does as well.
  9. I have a 2015 Honda Accord Ex-l coupe.  The shop that installed my gear tapped the signal after the factory amp, which then goes into a JL Fix before going into a Vxi 1000/5.  I told them about your build and some of your comments.  They wanted me to ask you where you tapped the clean signal, adn exactly how you did it.  I did not see specifics.  Would you be willing to fill me in?  

    1. keep_hope_alive


      My build log has information and I have a thread on the process of transplanting a premium touch screen into my Sport. 


       You can get wiring diagrams for your 2015 from my onedrive account:


      In those diagrams are the pinouts for the head unit and amplifier.  The output from your head unit is 3V RMS Balanced with no eq.  This can be wired directly into the VXi (you have the same amp as me and I was one of the Beta testers).   You can intercept the wiring from the amplifier input harness and eliminate the Fix entirely.  The input harness has front, rear, and sub input signals.  Because the inputs are balanced, you do not terminate the shield.  Your installer can solder RCA ends to wiring that intercepts the HU output.  If they need any other info, just hit me up.

    2. Justin Garrett

      Justin Garrett

      Thanks so much!  I was just reading your review of the amp when you replied.  Would you please explain what you mean by  "I achieved this by routing the signal through the preouts then back into the amp.  This gives me full control/tuning of the preout channels."



    3. keep_hope_alive


      You won't need to do this with a clean signal, but you can gain an overall EQ by bringing the audio signal into CH 1&2 then internally routing to the PreOut L&R.  Then connect RCAs from the PreOuts to CH5&6 inputs. 

      With this process, you cannot maintain a fader at the HU (you can use the remote control for a fader). 

      This gives you the tuning capabilities of the PreOut as a signal correction which i've used to correct for EQ.  My build log has some of those images and I have a video of the process I will soon add to my YouTube channel. 

      Tell your installer they can use an RTA to see the frequency response of any head unit or out of any amplifier to check if it is flat or not.   I used this process to fix the factory signal with the VXi.  





  10. keep_hope_alive

    New radio overheating

    Ah, then you would need a line output converter to take a speaker level (high) signal down to a line level (low) signal.
  11. It's not that you'll get better volume from one speaker per channel, it's that it will be safer in the long run. You will be louder with an external amp over just a head unit. And it will sound better at higher volumes. Without an enclosure, the lower frequencies cancel. you can hear this by listening to a speaker out of an enclosure vs. in and enclosure (before you screw it into the box, power it up, play music with some bass, and listen with it out of the enclosure vs. in. Speakers with ports behave as if they are enclosed except the have a port that resonates and affects the air-spring compliance of the enclosure at some frequencies. An equalizer adjusts frequency bands. A mixer combines multiple music sources. The preset settings for Rock is typically enjoyable. You can get an amp that can provide 300W per channel but set gains and volume level so only 1W is actually provided. Typically, you want more power available than you need since max power output includes max distortion.
  12. keep_hope_alive

    New radio overheating

    you will need to turn the amp on, for sure, using the remote output from the HU (note this wire cannot power the factory amp, it can only send a low current turn-on signal). you also need to adapt the head unit outputs to the amplifier inputs - this may require changing voltage ranges. PAC audio, Metra, and USA Spec sell interfaces for this purpose if you search for your year/make/model/trim of your vehicle. Given that the factory amp appears to use a low voltage arrangement with a common shield, it is possible you can just wire the RCA outputs on the head unit directly into the factory wiring (i.e. FL +, FR +, Front Shield).
  13. Howdy, old cars are fun. I recommend some reading up on terminology and concepts as you enter into the endeavor. www.bcae1.com is recommended for getting a grasp on what each component is and what they can do - use the shortcuts on the right of the screen to jump to topics such as "crossover or xover". I assume the text you quoted is from an amplifier and not the mechless head unit. Please share the model number of each of your components so we can make specific recommendations. Sounds like you did wire the speakers in parallel. It is not likely that the amplifier or head unit will be happy with that arrangement. The head unit only wants one speaker for each output, more than one speaker per output will cause it to run hot and eventually fail or shut off. Most old speakers suffer from foam surround rot or deterioration. Some used cloth and last forever. You can mix up speaker locations but you are unlikely to be happy with just tweeters in front. Tweeters without corresponding (and closely located) midrange drivers usually sound poor. You're likely to be happier with just loading up the rear. Note that enclosures improve how a speaker sounds and you need to separate the rear airspace from the front as good as possible. If you put a pair of 6x9s in dedicated boxes in the rear and combined that with a 10" subwoofer, all you'd need is a 4 channel amplifier to power it all.
  14. keep_hope_alive

    Will not power on

    A bad connection for the faceplate can cause a unit to appear dead and not respond. I agree that fuses should be metered to verify (i measure voltage on each side of the fuse at the exposed metal tab end)
  15. keep_hope_alive

    Options for 2009 Pontiac Vibe Audio

    Dealing with failures in stock head units and the associated input adapters is a common problem, regardless of make/model. Replacing with another stock unit is likely to result in the same problem. Putting an aftermarket head unit in is the preferred solution. You can spend as much or as little as you want with this option. The FM input options sound pretty terrible. Another option is to open up the factory radio and try to diagnose/repair the AUX input.