TonyD'Amore
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Posts posted by TonyD'Amore
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Um, if i am understanding THD correctly, then the DD-1 must have an internal filter,(like a 39.99hz to 40.01hz, and one similar for 1k.
It samples both what goes through the filter and also samples what does not. So once whatever does not go through the filter is above .99% of the total signal it lights up the distortion light.
Or am i way off here.
That could possibly create a situation where if for some reason you were processing the signal and it was effecting 40hz, the dd-1 would show distortion sooner. Because on an o-scope you would just see a waveform, and not notice if the frequency shifted.
edit:
i mean the user may not notice an effected(sp) signal
You aren't too far off, but in your example of 40Hz, everything that is in the signal that ISN'T 40Hz isn't harmonic distortion, it is just noise. So removing the 40Hz signal and measuring what is left over isn't measuring harmonic distortion, it is measuring noise. Harmonic distortions happen at precise frequencies, so in the case of the DD-1 it has to measure the fundamental frequenices, and the harmonic frequencies (at the same damn time), then compare the ratio of the amplitude of these things.
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The difference between when the DD-1 reads distortion and when it is visible by a human eye on a scope is fairly negligible, IF it is distortion caused by clipping. In terms of dB it would be within a couple of tenths, not 6.5dB, not even 1dB. If the distortion is caused by something other than clipping, there will be a huge difference between the DD-1 and a scope because scopes don't display distortion in a manner that a human eye would be able to read.
If I had to make a guess about what happened here, assuming that everything was done correctly and everyone is being honest, I'd guess that the amplifier in question is dirty to the point that it is over 1% THD wayyyy before clipping. This is what the DD-1 saw, thus it said "hey I see excessive distortion". It is up to the operator of the device to determine the source of said distortion. When used to set gain, if you start with the gain down and the correct overlap track and the DD-1 reads the signal as clean, and then one proceeds to turn up the gain until the distortion LED illuminates you are pretty guaranteed that the distortion it is reading is due to clipping and you have now set the gain properly. HOWEVER, there are some seriously dirty noisy ass class D amplifiers on the market these days, and the DD-1 will call them out every time. The DD-1 is pretty amazing, but it's not magic or psychic. If this were happening in my install, I would check the signal from the front to the rear making sure everything stays distortion free throughout the entire range of the volume control (up until the point where we know the source distorts). If that the signal is clean all the way through the volume range, but distorted at the amplifier intermittently or continuously throughout the volume range, then we know exactly where the problem lies.
Without seeing any of what happened first hand, this is my best guess.
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Seriously though, do you have smaller connectors you could terminate these with? I'm really interested. The set of cables I have now have slightly shorter ends and they make my deck stick out of my dash lol.
The rubber boot at the end can be removed, it is only cosmetic really. The strain relief for the cable is inside the barrel. This might help, or we can offer 90 degree adapters.
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What's the flexibilty like with the coaxial? Being a solid center conductor and foam dielectric? Also, is it single or quad shielded? Thanks in advance for any info.
They are double center conductor, stranded not solid. Each channel has it's own copper braided shield
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Maybe I'll invent a keyboard that has a bitchslap button for you homie
lets do it!! LOL
ok we need a photoshop of the SMD BSLP-1
right!?
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Maybe I'll invent a keyboard that has a bitchslap button for you homie
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Looks like a video is needed
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The AD-1 was designed to NOT NEED a bench or any lab equipment. It contains everything you need already. Put it on a cart, wheel it over to the vehicle that needs to be dyno'd, connect it to the amp. Done. Real in car dynos is what it is about. This provides the dealers a route to sell upgraded alternators, batteries, and wiring....as well as real amplifiers.
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.46 DB increase, is a HUGE increase at that SPL level. Different voice coil temps, or whatever is not going to make a .5 db diff. Maybe in a Extreme vehicle.
Cody, Every amp has a sweet spot, A spot the gain likes to be. Also try messing with the phase if your just running 1 amp, or 2 amps strapped. If your running more than 2 amps strapped dont because you wont be able to achieve the same phase on each master amp.
10 X LOG (.46/10) = 11% power difference. 11% power difference = 11% impedance difference. So from 1.00 ohm to 1.11 ohms. Totally possible with very little heat.
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These are shipping now!! Black Friday Sale time!!
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The D'Amore Engineering AF subwoofer line is shipping now! Just in time for the holiday. We are running Black Friday Week starting tonight at 8pm. These are single 4 ohm coil, LOW Bass in a small enclosure, very low distortion, VERY musical subwoofers. The coils are around 3.5 ohms making them great for a single woofer on a single Class A/B amp bridged, or a 3 or 4 subwoofer system on a 1 ohm stable mono amplifier. EVERY single one of these is fully tested before they leave here and come with the ACTUAL T/S parameters for that specific woofer!!! An industry first?
Take a look at them here: http://www.damoreengineering.com/subwoofers.html
For the sale, here is what we are doing:
Buy 1, get 1 at 50% off
Buy 2, get 1 free!
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Just ran t/s specs on the same sub(DC Level 3 10 dual 1 ohm) series and parallel.
Series-
Re-3.0 ohm
Fs- 33.4hz
Re+Res- 29.1 ohm
Ro-9.81 ohms
Qms- 5.55
Qes- .57
Qts- .52
Mms- 224.77
Cms- .000101
Sd- 50.27 sq in
Vas- .53ft3
Parallel-
Re- .70 ohms
Fs- 33.4hz
Re+Res- 7.5 ohms
Ro-2.29 ohms
Qms-5.75
Qes- .59
Qts- .53
Mms- 265.77
Cms- .0000854
Sd- 50.27in2
Vas- .45ft3
I am no speaker builder and dont really know what these numbers mean, could someone tell me if it looks like I did this correctly?
Just curious, what are you using to add mass to the cone?
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Just ran t/s specs on the same sub(DC Level 3 10 dual 1 ohm) series and parallel.
Series-
Re-3.0 ohm
Fs- 33.4hz
Re+Res- 29.1 ohm
Ro-9.81 ohms
Qms- 5.55
Qes- .57
Qts- .52
Mms- 224.77
Cms- .000101
Sd- 50.27 sq in
Vas- .53ft3
Parallel-
Re- .70 ohms
Fs- 33.4hz
Re+Res- 7.5 ohms
Ro-2.29 ohms
Qms-5.75
Qes- .59
Qts- .53
Mms- 265.77
Cms- .0000854
Sd- 50.27in2
Vas- .45ft3
I am no speaker builder and dont really know what these numbers mean, could someone tell me if it looks like I did this correctly?
That looks fantastic actually! The numbers should be the same whether parallel or series. With the exception of the impedance numbers obviously. Nice work! Very consistent
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Is that Tony doing the soldering?
That would be Juan, notice his Palmolive soft dish washing hands lol
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All components are now at D'Amore Engineering HQ. They will be in pre - production while we are at SEMA (owner's manuals, boxes, harnesses, ect), and full assembly promptly when we return from SEMA. We will be shipping by the 8th I'm sure. We might setup a webcam on the production of these starting on the 5th
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One minor problem here. Lets assume a 300 Amp alt at 14V = 4200 watts output. Assume 80% efficiency to convert the energy: so input to the electric motor = 5250 watts. So at 110V that would be 48 amps (not gonna happen). You would need a 30 Amp 220V setup with a 7 horsepower motor. Cool idea though
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Here is the link, feel free to leave feeback. I'm sure there may be a typo or two, please let us know. Follow the link to the IM-SG page.
direct download of entire manual here:
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With all of that being said, what would or could be the reason for a .5db increase in score? The TL doesnt lie.
All setting the same for both tests and amp tuned with dd1 with same track for both test.
6Vac input voltage- 155.71db
.33Vac input voltage- 156.17db
I don't know CJ, we are talking 0.46dB. If the voice coil temperature changed between runs you might see this. Can you get those results consistantly?
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CJ, you've Peaked my interest here.
Is It unreasonable to think there's head unit voltage drop?
AC voltage output X amplifier internal gain.
Scenario 1: .35VAC x 10
Scenario 2: 10VAC x .35
Assuming amplifier internal gain is a constant, voltage drop at the headunit is going to change which scenario more?
The RCA output voltage will not drop with B+ voltage dropping. The RCA outputs are fed from a mini-amplifier inside the headunit that has feedback. Think of it as regulated
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so in the end if you have a cd player with a 6 volt preout and a cd player with a 4 volt pre out and the amp can be set to 50volts with out clipping and has an internal gain of 10 volts the cd player with the 4 volt pre out would be able to allow you to push you equipment to its max with out clipping while the cd player with the 6 volt preout would create more clipping and only hurt the output and sound quality of the system.
I noticed this personaly on my own ride. I have Chrysler 300 with the stock HU that has a Rockford BLD (3Sixty Line Driver) for the added sub stage . My sub stage is a fully upgraded single 10" DC XL m2 running off a DC 2.0k. The line driver has 2 modes Balanced and Unbalanaced. In Balanced mode it produces 22 Vrms and 11 Vrms in Unbalanced mode. When setting my gains (line driver hace a gain as well) with the DD-1 , I noticed that in balanced mode I get full time distortion on 0db 40hz track. But in balanced mode I can addjust the gains slightly (if at all).
Also when I set the amp if I use the -5bdb track on Unbalanced mode I'll get full time distortion decteted on my DD-1.
The reason the BLD is 11 Vrms unbalanced and 22 Vrms balanced is because in unbalanced mode it puts up to 11 Vrms on the center pin of the RCA and grounds the shield. In "balanced" mode it puts 11 Vrms on the center pin of the RCA AND 11 Vrms on the shield!! If your amplifier doesn't have balanced or differential inputs, you are shorting the BLD out in balanced mode. Take a digial meter, set it to ohms, with the amplifier not turned on and the RCAs disconnected measure the resistance from battery ground connection to RCA shield. Let me know
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RCA voltage will have no affect on efficency. Every amplifier reguardless of class has some internal gain. Lets say than an amplifier puts out 50 Vac RMS before clipping. Lets also say that the internal gain on this amplifier is 10. That means that it will take 5Vac of input to drive the amplifier to clippling. ( 5Vac X gain of 10 = 50Vac ) The "gain" control on the amplifier is to "gain up" whatever signal is coming in, up to the 5Vac that is required to drive the amplifier to clipping.
Example A: There is only 1Vac input to the amp. We adjust the external gain control to have a gain of 5 to drive the amp to clipping. So the 1Vac coming in goes through the "preamp section" of the amplifier where the gain control gains it up to 5Vac. The signal then goes to the "amplifier" section of the amplifier where it internal gain is 10 so now our amplifier puts out 50Vac. The gain pot on this amp is probably 1/2 way up or so
Example B: There is 5Vac input to the amp. We adjust the external gain control to have a gain of 1 to drive the amp to clipping. So the 5Vac coming in goes through the "preamp section" of the amplifier where the gain control does nothing so the signal is still 5Vac. The signal then goes to the "amplifier" section of the amplifier where it internal gain is 10 so now our amplifier puts out 50Vac. The gain pot on this amp is all the way down.
Same result, no affect on efficency or power output.
The only possible difference between example A and example B would be that B could potentially have a slightly "cleaner" signal since the signal would have less chance of picking up alternator whine or other noises as the signal travels from source unit to amplifier.
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We are talking about input voltage on the RCAs correct? Battery voltage is not part of this question?
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not everyone likes the dd-1? some rude comments
in SMD Distortion Detector (DD-1) Topics
Posted