Audioque HD3 owners. . . tuning question

[prochobo 10+ year member]

Have any of you noticed that your sub peaks below tuning frequency? For example with mine -

tuned to 37hz, it peaks at 32.

48hz peaks at 45hz

50hz peaks at 45hz also.

They say this sub is designed to play well below tuning frequency, but peak below tuning? Maybe somebody can shed some light on this.

I've also noticed that this sub is kind of peaky. Might just be the box size though.

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[dleccord 5,000+ posts]

peak as peaking below box tuning? mines have always peaked 7-10hz higher than tuning

 

[prochobo 10+ year member]

peak as peaking below box tuning? mines have always peaked 7-10hz higher than tuning

Yep. . peaking below box tuning. I'm using 3 4" aeros. Peak was taken at the headrest also.

 

[Jeremiah25 10+ year member]

How are you determining your tuning frequency? It may be a calculation error, because you "should" peak higher than the tuning frequency.

 

[prochobo 10+ year member]

How are you determining your tuning frequency? It may be a calculation error, because you "should" peak higher than the tuning frequency.

Exactly what I'm thinking, peak higher than tuning. I used WinISD for port calculations.

3.6 cubes after displacement, 3 4" external aeros (subtract 1" for usable tuning length)

9" length = ~50hz, peaked at 45hz

3.6 cubes after displacement, 2 4" external aeros

6" length = ~ 48hz, peaked at 45hz

12" length = ~ 37hz, peaked at 32hz

Measurements taken with TL at headrest with a 20-100hz 0db sine sweep.

 

[dleccord 5,000+ posts]

i know it might be a dumb idea but did you try 55hz vs 45hz when you had the box tuned to 48hz instead of running a sweep? do you think the pressure build up might throw the tl off as well? was this at max volume?

 

[prochobo 10+ year member]

i know it might be a dumb idea but did you try 55hz vs 45hz when you had the box tuned to 48hz instead of running a sweep? do you think the pressure build up might throw the tl off as well? was this at max volume?

I ran the sweep at 3/4 volume. I'm going to try higher tuning (59hz) if it stops raining today and see where that takes me.

I did not try 55hz vs 45hz (didn't have any single note tones on me), so I tried different songs that I know peaked at certain frequencies.

Throw it up peaked at 49hz - 141.4

B*tch off the Kings of Crunk CD peaked at 49hz - 142.2

Show Stopper peaked at 45hz - 140.x

Weird, same settings and everything, sweep revealed a 45hz peak.

 

[dleccord 5,000+ posts]

yeah at about 3/5s of the voume i peaked below tuning as well. do it at max volume.

i think you need more port area. either port front or back. i bet you can increase a few DBs that way.

 

[prochobo 10+ year member]

yeah at about 3/5s of the voume i peaked below tuning as well. do it at max volume.
i think you need more port area. either port front or back. i bet you can increase a few DBs that way.

Aiy yi yi, I'm too scared to do a sweep at max volume //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif

I might try another port, but 4 4" seems to be a bit overboard for a single 15". 2 4" caused port noise at lower frequencies, but adding another one solved it.

So far, the loudest placement is:

Sub front, driver side

Port passenger side

Box all the way back

 

[dleccord 5,000+ posts]

only about 37sq inches of port?

 

[prochobo 10+ year member]

only about 37sq inches of port?

They're flares and flares work wonders, at least in my car.

 

[skmfkr 5,000+ posts]

mine seems to peak at around 42hz but thats by ear

2.4cF@35hz 12"

 

[Phreaker 10+ year member]

yeah at about 3/5s of the voume i peaked below tuning as well. do it at max volume.

Wha?!

Umm wouldn't that cause your HU to send a clipped signal if you did max volume?

Hell alot of HU's start sending off a clipped signal at less than 3/4 of max volume......what gives,how the hell do you achieve an un-clipped signal with max volume?

 

[dleccord 5,000+ posts]

3/5 of max volume. my max is around 22/35. that is where i set my gains. well i had the volume at 15 and i peaked at 42hz, and i was like no way i peaked that low. turned it up to 22 and im at 49hz

 

[Phreaker 10+ year member]

3/5 of max volume. my max is around 22/35. that is where i set my gains. well i had the volume at 15 and i peaked at 42hz, and i was like no way i peaked that low. turned it up to 22 and im at 49hz

TY for clearing tat up...at first I was like nooooooo clippage FTL but now I understand....

I need to find the max unclipped volume for my HU which doesn't go from 0 to 35 but actual goes from 70 as the lowest volume and 0 as the HU's max volume but we all know that would be clipped as a mother f'r.

3/4's of 70 is 18 and the HU originally cost $250+ BN but it is a Sony HU,Sony CDX-M630 is the model.