TUNDRA AFTERMARKET AUDIO UPGRADE RTA RESULTS

Hi Everyone,

I am really curious about all of your audio systems. I am wondering how many here tune their systems with an RTA and have RTA curves that you can share with the group?

I would love to see RTA curves for everyone's install and see how well each system performs.

I will kick it off by posting my RTA results for my system and am looking forward to seeing yours.

Happy tuning!

 

I look forward to you bringing your RTA to my house so I can show you my results...

 

How different was the sound curve on your dsp vs the rta?

 

I just got into this after buying a minidsp. I love the parametric EQ. I dont have an RTA graph on hand but I use REW for my analysis and have been working towards the audiofrog house curve but with a little more emphasis in the 100 -300 Hz range.

Can you time align with your system and/or EQ each side/driver independently? Those are key components imho to getting great sound. Oh and just turn off the rear speakers: they do nothing but dilute the soundstage.

 

Sorry, that is an expense you will have to bare. You are welcome to drive to my location.

 

There is no curve on the DSP. Only what is analyzed when playing pink noise through the system to generate the RTA curve. Once the RTA analyzes the signal it analyzes the system output and displays the signal on the RTA's display which is utilized to tune your EQ to correct the system response.

Initial curve looked like the shot below.



Then adjusting the EQ in the DSP to bring the frequency response in to where it needs to be for accurate sound.



The end result is the following EQ Curve.

 

Your adjusted curve is a typical house curve. Is that a parametric EQ dsp? If so I am jealous of the number of filters you can apply. The minidsp has 6 filters per output channel plus 6 per input. So I can use broad strokes on the left and right input separately as each right and left + sub have 6 filters at the input. And then I am using one channel for each midrange, tweeter and a single sub channel. So on the output side that effectively gives me 12 filters per side plus the sub. I have a peak in the 1K range which is noticeably producing ear fatigue and a dip around 500Hz which is not responding to EQ so is likely a boundary condition due to the truck cabin dimensions.

What kind of microphone are you using? I have the UMIK-1.

I am planning to start all over again tomorrow with the idea of focusing my filters first on the middle of the range including that 1KHz area. It is tough as the model I am following has you tune one side to the house curve and then the other side is tuned not to the house curve but the first side tuned. (Which makes sense as matching the sides is important for soundstage and reducing harshness.) Then you play all drivers and measure and look for problems. It is this last part that is tough because I only have so many filters, it is hard to fix issues that only pop up due to interference with all drivers on.

Have you done any acoustic material work in the cabin? You can check out my build thread, but to put it short I spent a heap of time laying down CLD, CCf, and MLV. it is a noticeable improvement but each step had diminishing returns. If I did it again, I would focus on the front doors first and foremost.

edit: Interesting I see that you have a big peak in the 500 Hz range (nonEQd)so that puts my boundary condition idea into question. I do have that same broad peak in the 120 Hz area that only becomes apparent with both sides on. Otherwise it actually looks like a dip.

 

and check out diymobileaudio.com for the deep dive

 

There is a parametric eq available in the PS8, but I don't like parametric eq's. So I am using 33 bands of equalization out of 264 available bands of equalization. With the PS8 you can EQ each channel individually with its own 33 band 1/3 octave EQ. The reason that I am only using the final 1/3 octave EQ is because I typically test and tune each individual drivers enclosure and tune it to get the best performance from an individual speaker. So the 6.75" drivers are optimized in their enclosure to perform from 500hz to 5500hz, The 8" drivers enclosures are optimized to perform from 50hz to 550hz and the 12" subs are optimized to perform best in their enclosure from 16hz to 50hz. The steep Butterworth 48 db per octave crossover slope is a must to keep each speaker performing in its wheelhouse.

Tweeters were optimized by placing them in 3 different locations and using a lot of reference music material that I have tuned competition systems with for 30+ years. Then settling on the location that provided the best front stage that was about ear level. and where the reflective properties of the vehicle created the illusion of sound beyond the confines of the trucks cab. Playing Yellow's Flag album the song The Race you can hear the car coming from about 25 feet to your left and they passing in front of you in the vehicle and disappearing about 25 feet to your right of the drivers seat.

There is quite a bit of acoustic treatment in the cab of my truck. Its all Dynamat. The front door panels are fully covered on the back side and the front doors themselves are treated in areas where they resonated.

I dont have any dynamat in the rear doors as they dont have any drivers that are active in them and they dont resonate with the system the way it is set up.

The nice thing about the ARC Audio PS8 is you can shut off each driver in the setup. That way you can tune and level each driver individually. So if you run in to acoustic problems you can isolate them and correct them very quickly.

 

Dude! Come over and help me tune my truck. That dsp is awesome sounding. I tried EQ each driver individually but I didnt get great results but I am very new at this. Of course, I am regretting a little not going with a dsp with more tuning filters per channel but c'est la vie.

Tell me more: tips specific to trucks, working with a 2 way plus sub system etc.

edit: and pics...lots of pics like the tweet location etc.

I am running stereo integrity m25 tweeters and rockford fosgate (not very good but hey) 6.5s in the stock locations. Two alpine 8 inch subs in a q logic box that takes the place of the rear underseat compartment. 70 W to each driver and 500 W to the subs wired in parallel. Added a protective capacitor to the tweet and ran new speaker wire to every driver.

 

Thats exactly what I wanted to see...what the adjustments you had to do inorder to get the ultimate curve you have.
Did you listen to your system with a flat curve before you decided to shoot for the curve you have?

 

Yes, I adjusted the system based on how it performed from the flat curve.

 

Well, shit. It was worth a shot...

 

I am dying to install my stuff. I bought à Mosconi Pico 8[12 DSP. It is 60w x 8ch plus 4 more outputs. I've had it for probably 2 months and it's still in the box. I hate it just sitting there but I work for myself and I feel all I do is work. One day, gotta find a sub amp though. I also have a linear-x RTAJr, but I really only used it for SPL. LoL

 

If you get a chance look through the thread in my signature. It will show you my install. It should give you a good idea of what I have done. The issue with trying to achieve a great sound stage in the tundra without DSP will be getting your front stage, in your case the two way set up so that the speakers are equidistant to your ears. My recommendation would be not using the door locations as they dont lend well to imaging. Also you may find that the door speakers tend to cancel each other out as they face each other directly across from each other, door to door. My recommendation would be to get something similar to the Q-forms so that the door speakers are at an angle like my kick panels are. Then the best placement for the tweeters is to place them in the dash left and right side locations facing up. They reflect well and its the furthest distance from your ear in each location. You can try placing the tweeter down in the Q-From tweeter location as it will be more equidistant for the tweeters from the left and right position. But I caution that this may also pull your sound stage lower in the vehicle.

 

Come on over, always happy to help a fellow installer improve their system.

 

I just read your build thread. Thanks for that. How are you time aligning the in dash tweeters? Do you time for the reflection or not?

 

With time alignment you always measure from the speaker to the drivers left and right ear. So the tweeters are measured from their physical mount location. Left tweeter to left ear, right tweeter to right ear. The reflection is a benefit that creates a better illusion of elimination of the vehicle interior boundaries.

 

I havent used an rta to tune yet mainly because my eq is limited, but i gotta say, your rta curve is pretty much on point. Must sound damn good.

You also used a real rta, damn man. Lol.
If and when i decide to tune my system properly im going to use either the minidsp calibrated mic or the parts express calibrated mic. The minidsp one is quite a bit more expensive but it works with rta wizard on pc.

 

I am using the UMIK-1 with REW rta software (free).

 

Does it provide its own pink noise to set the system with or do you have a pink noise CD?

 

REW has many options which includes pinknoise. You can do sine wave sweeps, impulse stuff, etc. Way more than I know what to do with. It has a built in RTA as well. Great software that a lot of people are using now. So I can use my laptop with both the UMIK-1 plugged in and a 1/8 inch jack to run pinknoise (or whatever) to the HU and analyze all on the laptop.

My one frustration now is that my dsp only has so many filters and I wish I had more. I have read some non conventional tuning techniques including just picking frequencies centered in each octave (the number depends upon the number of filters you have) and then using a sine wave at each frequency and simply adjusting the left right gain so that each frequency is centered. I think this idea is intriguing but I would first try to get the overall response close to a house curve first (like your final RTA curve).

 

Start by setting your EQ flat all the way across the frequency band. Using pink noise the best thing to do is set all of your speaker levels for the drivers ears, so place the mic in the location of your left ear, then set the volume to 76 to 80 db with the left tweeter note exactly the DB you set it at. Then set it at the exact same level for the mid on the left. Then the sub on the left. get them all perfectly balanced on the left, then do the right channel tweeter, set it at the right drivers ear at the same level you set the left at. Then the right mid to the right ear at the exact same level, then your sub at the right ear and the exact same level. Once you have done that you should have a perfectly balanced system and you can begin to tune.

Now look at your RTA frequency response to determine how far out each speaker is. Start with your tweeters and mids first these you will want to use my curve as your goal.

The bass (Subs) you will adjust last because they will be the hardest to get right. A lot of people over power them and they sound muddy and distorted. You want them to sound natural. you will want to boost them 4 to 6 DB above what your mids are at. It will give you a nice natural sound. If you have a well tuned system you will start to find fault with recordings. You will know how a CD was recorded or how bad a MP3 file truly is. The system should be able to play any type of music accurately without adjusting anything when you change between Rap, Classical, Jazz, Electronic, Dance, Big Band etc... A good system will play them all accurately. Accuracy is the key.

Anyone can make a system loud, very few people are able to tune a system that reveals flaws in recording methods and really shows off well recorded music.

The other thing you will notice if you set it up correctly is that you will keep lowering the level of the volume as it will sound really loud over time without you realizing how high the levels really are.

 

Thanks for the tips. Pretty much lines up with the ideas on diymobileaudio.com.
If you haven't checked out that site yet, I think you'll like it. Lots of people that compete there.

 

thanks, I am a member on that sight.

 

BTW: here is a snapshot of my RTA from last week. (1/12 octave smoothing) Note that nothing below 400 Hz was touched as I was (and am still) trying to deal with a sibilance issue which is at least partially occurring at 6.3 kHz. The nice curve in the background is the audiofrog house curve and the other two are the right and left side. The dip around 450 Hz seems to be a node from the truck dimensions.

 

Yeah, thats the setup im going to go with.

Oh, wow. You got the audio frog components? If you did thats awesome.

 

No audiofrog. Just bought the Umik with a minidsp.

The curve was constructed by audiofrog and you can download it from their site to import into REW as a starting target. I will likely attenuate my final target curve somewhat from this one on the upper end and bring up the midbass a bit.

 

I think that the curve you have posted is pretty interesting. There is a 20 DB swing between the bass level and the treble rolling off at the upper end. That is a lot of dynamic difference. Hopefully you will be able to reign that in once you start tuning.

 

I know that seems like a lot. I definitely like a bass heavy sound and just messing around without measuring, I often end up attenuating the upper end further but I think this is due to sibilance. Many curves that people are using swing somewhere in the 15 dB range. (JBl, Crutchfield, etc.) I havent had time to tune lately but my biggest issue is still something in the treble end. The sibilance is better but I think I can reduce it further. My next attempt will use the HU EQ to tame things first and then use the dsp filters modestly. Meaning I am going to refrain from trying to get dead on that target curve and rather leave some filters available so that once i listen to some music, I can fine tune. It is really tricky business!

I also take in your comment that any genre music should sound good with a proper tune, assuming a good recording. Boy, I am far away in this regard. Electronic music seems to always sound the best, I guess it is the nature of the recording, but classic rock is really missing a lot in my system. I want to blame the weakest component which are the 6.5 rockford drivers but I do think that I can still get them to sound a lot better with a better tune.

I just keep reading and trying!