# Averting stupidity



## Holmz (Jul 12, 2017)

I have a k$ or 2 or more in head unit, Amps, and crossovers.
This is all old school (no DSP). And it seems odd to have $100 speakers in the system.

Head unit goes into a 3-way crossover.
35w/channel, for both midrange and tweeter...
And 70w/channel for the woofers.
Still need to work out the subwoofer, but a single Morel Ultimo seems like it is in the running.

This all about sound quality and not about SPL and competitions.

Here is what I am looking at for a large 4x4.

*Front*
In the front, on the dash pointed at the windshield...
Woofers: Peerless PPB 830874 - 6.5" Poly Cone Woofer
Crossed over ~120 Hz to 1kHz

Midrange: scan-speak 11m, 12mu, or 10f
Maybe crossed over ~1kHz to 6kHz

Tweeter: Mundorf AMT17D1.1 Dipole Air Motion Tweeter
Mostly because the off-axis performance is good, and then aim the passenger side towards the drive and visa-versa.
Crossed over ~6kHz

*Rear*
Midrange and tweeter the same as the front, or maybe a coaxial???

Plus A single Morel Ultimo SC 102 + some amp... in a sealed box in the back of a large 4x4.


Basically I am trying to figure out what to run for speakers and where to put them. No real pillar space and likely the front dash mounted is easiest, with the speakers ~ 1-1/2 feet in from the side windows. This all assumes that aiming the speakers to bounce off the windshield is sensible. The woofers may be able to fit into the doors??

I can put some treatment I the headliner, as well as the door panels.
Total sound SPL will be relatively low. But the focus is for sound all day long, and not fatiguing.

No real easy way to figure out what may be good and what may not be good, nor how much to budget and where I should focus the funds (midrange, tweeter, sub and woofer??)

So any insight into working out how to go about it is appreciated.


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## Holmz (Jul 12, 2017)

Does no one have any wisdom to share?

Tweeters: I now have a set of scanspeak D3004s en-route. They may be a bit beam prone for a dash mount, but I will see.

Midrange: Also looking at GB25 for the mids or some other small midrange which does not beam too much. Maybe a bit inefficient for 35-40W?? But maybe Ok.

Woofers and/or sub: I still no ideas.


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## Jscoyne2 (Oct 29, 2014)

Holmz said:


> I have a k$ or 2 or more in head unit, Amps, and crossovers.
> This is all old school (no DSP). And it seems odd to have $100 speakers in the system.
> 
> Head unit goes into a 3-way crossover.
> ...


Hi Holmz, Lets see if i can help. 

Okay, first off. The entire point of the DIYMA community is basically to prove you don't need expensive gear to sound great. There are lots of people who have spent under a grand into a system and had amazing sound systems. 

There are lots of times when a $100 speaker outperforms many top dollar brands. For example, when we talked earlier. i recommended you the Scanspeak 10f, this is a $95 4'' mid-range that outperforms the Hertz hl70(which is part of a $500+ 3 way set.) in every way. I say this from personal experience. 

Another thing DIYMA preaches is that install and proper tuning triumphs driver choice in almost every occasion. Good amplification, proper install and deadening of doors or kicks or wherever speakers are mounted and a good DSP can make a stock system sound fantastic. 

So lets talk about your personal install. Is your 3 way crossover an passive one or an active one?

Does it look something like this? 









or more like this









I've talked with you before about how 35 rms isn't a lot and ill stick by that. I would seriously consider upgrading your amplifier. Also, its worth noting since you state this is an old school install, that old school amps are highly inefficient and if your using one, you'll be pulling more power than you think, even at 35rms. It shouldn't be an issue, but is worth knowing. 

70 for the woofer is just under minimum in my opinion as well. i think 80 on a 6.5 would be fine. There is debate on actual rms needs of a tweeter but 35rms on a tweet may sate your needs. 

You also state that you want to put a sealed subwoofer in your system. You should know that sealed subs aren't known for getting very loud without a good amount of power to them. A sealed sub on 100rms isn't going to be anything you'll be happy with. I guarantee it. 

How do you intend to fit a 6.5 into your dash? I am assuming your truck has stock 6.5s in the dash? i'd like to see some pics of that if its at all possible. If it is indeed dash 6.5s, make sure that the back of the speaker is completely isolated from the front. Keep in mind that your 6.5 would be firing directly into your dash and with a good driver, and good power, comes rattles. 

Your crossover of 120hz and up may be pretty limited. I think you should be looking at more like 80 hz and up, unless for some reason, 120hz is your lowest hpf setting on your crossover. 

Before i get into the midrange/tweeter selection. I think you should consider what your goals are and why you are going with a 3 way. A good 2 way can sound very very good and should not be discounted. Without the use of a dsp and time alignment specifically. i would even go so far as to say you would be hurting yourself more than helping, with the use of a 3 way front stage. 

Your choice of midranges is fine but i think your crossovers are all over the place. You should be looking at more like 
sub 0-80
6.5 80-500
4in 500-5khz
tweet 5khz and up

or in case of a 2 way
sub 0-80
6.5 80-5khz
tweet 5khz and up

I believe AMT and ribbon tweeters are very sensitive to temperature changes. i could be wrong but you should look into it considering your country. A good aiming idea for tweets is on dash/A-pillar aimed at your center light between driver/passenger head. 

You actually dont need rearfill and that money would be better spent on better amplification. If you're dead set on it then coaxials work fine and there are lots of good coaxials out there to choose from.

Pictures of the dash and vehicle would certainly help us to figure out what good options for you would be. Do you have any fiber glassing experience?

Deadening your headliner and doors wont be necessary if you don't have any speakers or rattles in those areas.


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## Holmz (Jul 12, 2017)

First - I appreciate your taking the time for the thoughtful post.




Jscoyne2 said:


> Hi Holmz, Lets see if i can help.
> ...Pictures of the dash and vehicle would certainly help us to figure out what good options for you would be.
> 
> How do you intend to fit a 6.5 into your dash? I am assuming your truck has stock 6.5s in the dash? i'd like to see some pics of that if its at all possible. If it is indeed dash 6.5s, make sure that the back of the speaker is completely isolated from the front. Keep in mind that your 6.5 would be firing directly into your dash and with a good driver, and good power, comes rattles.


Looks like this (but this is someone else's actual truck - that looks more presentable):


















The dash on the instrument side comes off and the access is easy.

So I am thinking of mounted into the dash, and aiming up to bounce off the windshield. The inside is metal and there is not easy way to have them on the pillars as they are effectively a steel roll-cage.

Basically it is sheet metal panel that is tacked-welded onto the steel structure as two different metal types.
Later when the rusty panels are replaced, then people bond them on with Sikaflex (TM) to avoid future corrosion issues.




Jscoyne2 said:


> Crossover...


Yes it is active.












Jscoyne2 said:


> ...
> I've talked with you before about how 35 rms isn't a lot and ill stick by that. I would seriously consider upgrading your amplifier. Also, its worth noting since you state this is an old school install, that old school amps are highly inefficient and if your using one, you'll be pulling more power than you think, even at 35rms. It shouldn't be an issue, but is worth knowing.
> 
> 70 for the woofer is just under minimum in my opinion as well. i think 80 on a 6.5 would be fine. There is debate on actual rms needs of a tweeter but 35rms on a tweet may sate your needs.


Yes 35-40W for each MTR and each Tweeter (4 channels). The amp saws 40W/channel
So assuming that the sound is split evenly then the 150W/channel (40+40+70) is ˜21dBW. The speakers at ˜88-92dB-SPL/W would then yield ˜109-113 dBA... Maybe take away 15 dB to have some relationship between clipping, headroom (crest factor)... So I guess I should be able to have 95 dBA before clipping.
I am not sure if that is enough, but the OSHA standards seem like one way to think about it:

https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_id=9735

The amp unscrews off the back of the head unit, so the only extra was the 70+70 2 channel was extra.




Jscoyne2 said:


> You also state that you want to put a sealed subwoofer in your system. You should know that sealed subs aren't known for getting very loud without a good amount of power to them. A sealed sub on 100rms isn't going to be anything you'll be happy with. I guarantee it.


For the sub I am thinking a separate 350-500W amp???
The sub is not intended to be "old school", but the head unit is not overly flashy... and I can stuff the amps in behind the dash.

Maybe a ported would be better (30-Hz)... I need to consider where it goes, and need to see if there is room under the rear seats. 




Jscoyne2 said:


> ...
> Your crossover of 120hz and up may be pretty limited. I think you should be looking at more like 80 hz and up, unless for some reason, 120hz is your lowest hpf setting on your crossover.


Ok Thanks.
The cross over is tuneable so I think I am OK. Many of the smaller 4 and 5" woofers seem like they get happier about 120 Hz, but I have some work to do on volume and area.
It seems like the upper range of the sub and the lower range of the woofer are related. (I was looking at the 6.5" JBL Subs...)




Jscoyne2 said:


> Before i get into the midrange/tweeter selection. I think you should consider what your goals are and why you are going with a 3 way. A good 2 way can sound very very good and should not be discounted. Without the use of a dsp and time alignment specifically. i would even go so far as to say you would be hurting yourself more than helping, with the use of a 3 way front stage.
> 
> Your choice of midranges is fine but i think your crossovers are all over the place. You should be looking at more like
> sub 0-80
> ...


One reason for 3-way was to spread out the watts of the 4-channel.
Another reason was that I may need to shove the woofer a bit away from the MR and tweeter.




Jscoyne2 said:


> I believe AMT and ribbon tweeters are very sensitive to temperature changes. i could be wrong but you should look into it considering your country. A good aiming idea for tweets is on dash/A-pillar aimed at your center light between driver/passenger head.


I have moved away from AMTs to a used set of ScanSpeak D3004s.

But yes - I was thinking of canting the speakers to keep the off-axis angle even between passenger and driver (i.e. Splitting the difference).




Jscoyne2 said:


> You actually dont need rearfill and that money would be better spent on better amplification. If you're dead set on it then coaxials work fine and there are lots of good coaxials out there to choose from.


OK - Got it.
It does have 4 seats in the back, and some of time I may have some...
But I can delay and see if there is an actual problem, before fixing a theoretical problem.




Jscoyne2 said:


> Do you have any fiber glassing experience?


Yes to experience... and 100m roll of carbon fibre, and a vacuum pump (I need a bag).




Jscoyne2 said:


> Deadening your headliner and doors wont be necessary if you don't have any speakers or rattles in those areas.


The headliner is falling down in the rear section, so I need to do something anyhow... I was thinking Sonex tiles just because they are generally a bit loud with a diesel and the panels are sheet metal, so some Dynamat type of leaded vinyl would help to damp out drumminess.

I am sure I have a squeak or 3... But I can also tackle them later.

Your 10f speakers have 92 dB (compared to the others I mentioned which are only ~86dB), so that concept of 35-40W gets to look like a real problem with inefficient midranges (looking like they are on a 10W amp (-6dB), compared to your 10F - which are probably a better choice...)


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## Jscoyne2 (Oct 29, 2014)

Holmz said:


> First - I appreciate your taking the time for the thoughtful post.
> 
> 
> 
> ...


Irs 2:30am here and im gone camping for the weekend so someone else can chime in to help. Otherwise ill reply on Monday. 

Fyi. Most of us are in the U.S. on here 

Sent from my SGH-M919 using Tapatalk


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## Holmz (Jul 12, 2017)

Jscoyne2 said:


> Irs 2:30am here and im gone camping for the weekend so someone else can chime in to help. Otherwise ill reply on Monday.
> 
> Fyi. Most of us are in the U.S. on here


Enjoy the camping.

My daughter is on a road trip this weekend too (in the midwest).
She is night owl, but 2:30 is even late for her. :cwm33:


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## Holmz (Jul 12, 2017)

@Jscoyne2 Hopefully the camping was enjoyable.
So I preparing this in advance.

Here is where my confusion lies...
The spec sheet https://www.madisoundspeakerstore.c...anspeak-discovery-10f/4424g-4-midrange-4-ohm/ says:
100h RMS noise test 15W
Long term max power 30W
Sensitivity (2.83v/1M) 89.8 dB

So for a 4-Ohm system that is 89.8 dB at 2W. 40W provides 13dB at max power of 40W (compared with 2W).
I will have a 40W amp/ch feeding solely each midrange and tweeter from the 40Wx4-channel amp.

So the max sound calculates as ~102.9 .

Are you suggesting that really the 40W amp is operating at a crest factor of say ~15 and that therefore the max sound before clipping is ~87.8 dBA and that I need more of an amp to achieve a higher amount of headroom?
And that 87.8 dBA is on the marginal side of things?


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## Jscoyne2 (Oct 29, 2014)

Holmz said:


> @Jscoyne2 Hopefully the camping was enjoyable.
> So I preparing this in advance.
> 
> Here is where my confusion lies...
> ...


Your over complicating things way too much. Usually an RMS rating is based on how much power a driver's voicecoil can take with a full range signal 0hz -20khz. Once you start adding high pass filters. That rating skyrockets. My 10f is seeing 100 watts all day. In fact, in some cases, if you model a driver, you can find that it will hit max mechanical excursion before it ever hits its thermal rating. This is also true vice versa.

When i say that 80rms is a good idea. I say it because ive heard plenty of systems on headunit power (15rms), on alpine power packs(40rms), on amps with 100rms. To me, 80rms seems to be the minimum sweet spot for the amount of power to give to your speakers for a loud enough system for you to enjoy when you want to crank it. Less is possible as well as music is subjective and what "loud" is, is different for everyone. 

Everything about a speaker changes once you put it in a door or an enclosure. Looking at specs will only give you half the picture. We use specs for baselines to start with while keeping in mind that they will change once installed.


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## Jscoyne2 (Oct 29, 2014)

Holmz said:


> First - I appreciate your taking the time for the thoughtful post.
> 
> 
> 
> ...


i would look into something along of the lines of these. Dash pods would give you a decent looking set up and would be completely movable. 



















The crossover you posted won't allow for a "3 way" set up. There is some mix up with how we phrase things on here. 90% of the time, when we say 3 way on here. We mean 3 way front stage + sub. So 4 way all together. You're crossover is actually meant for a 3 way set up that includes the sub. So the Low settings are for your subwoofer. The mid setting is for your 6.5 and the high is for your tweeter. 

As for the sub and its power. If you can go ported, that'd be great but ported boxes are always bigger and room may be an issue for you. Im not sure what all your rig's space constraints are. 350-500rms is a great amount of power for a sub. 

Since you have alot of people in the back. Its not a bad idea to have coaxials but then you'd be looking at more amps to power those back speakers as your 4 channel would be powering the tweets and 6.5s.

We're kinda all over the place with topics so let me know if i missed anything. I skipped over a few things on purpose because i think i covered them in the previous post.


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## Holmz (Jul 12, 2017)

Jscoyne2 said:


> Your over complicating things way too much. Usually an RMS rating is based on how much power a driver's voicecoil can take with a full range signal 0hz -20khz. Once you start adding high pass filters. That rating skyrockets. My 10f is seeing 100 watts all day. In fact, in some cases, if you model a driver, you can find that it will hit max mechanical excursion before it ever hits its thermal rating. This is also true vice versa.
> ...



Is that "100W all day" from a single amp, then through a passive to the speaker?
Or is that 100W after an active cross over is feeding the amp tied directly to speaker?
Or
Is it a 100W amp with an active or passive, but we do not know what max voltage or wattage is being consumed by the speaker? ... Just that a 100W sounds good and it must be well past clipping.




Jscoyne2 said:


> When i say that 80rms is a good idea. I say it because ive heard plenty of systems on headunit power (15rms), on alpine power packs(40rms), on amps with 100rms. To me, 80rms seems to be the minimum sweet spot for the amount of power to give to your speakers for a loud enough system for you to enjoy when you want to crank it. Less is possible as well as music is subjective and what "loud" is, is different for everyone.
> ...


Was that 40W "Alpine power pack" an active amp wired per speaker? 
or
an amp supplying full spectrum through passive crossover to components or to a coaxial with a passive built-in?

And same for the 80W.
Is that 2 or 3 80W amps per side that sounds good, or 1 80W amp per side?




Jscoyne2 said:


> i would look into something along of the lines of these. Dash pods would give you a decent looking set up and would be completely movable.
> ...


This makes sense and then I can move it around and figure out later if I want to fix them in the dash or not. It is probably a great starting point and I can have the box the right size for a baseline.




Jscoyne2 said:


> As for the sub and its power. If you can go ported, that'd be great but ported boxes are always bigger and room may be an issue for you. Im not sure what all your rig's space constraints are. 350-500rms is a great amount of power for a sub.
> 
> Noted - thanks!


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## Holmz (Jul 12, 2017)

A couple more questions.

1) what would sound level be like (say 1/3 way up) using with a single amp into a passive cross over to components compared to an active into three 100W amps?
1A) My understanding is that they would be the same.

2) what would sound be like at the same 1/3 way up level using a 40W amp or amps?
2A) my understanding is that they would be the same.

3) What would the clipping/distortion be like with the single amp?
3A) my understanding is that the higher frequencies or midrange would be most affected.

4) what would the clipping/distortion be like with the 3 active amps?
4A) my understanding if that it would be worse on the woofer or midrange, and the tweeters would be the last to clip.

Do I have any of this right?


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## Jscoyne2 (Oct 29, 2014)

Holmz said:


> Is that "100W all day" from a single amp, then through a passive to the speaker?
> Or is that 100W after an active cross over is feeding the amp tied directly to speaker?
> Or
> Is it a 100W amp with an active or passive, but we do not know what max voltage or wattage is being consumed by the speaker? ... Just that a 100W sounds good and it must be well past clipping.
> ...


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## Jscoyne2 (Oct 29, 2014)

Holmz said:


> A couple more questions.
> 
> 1) what would sound level be like (say 1/3 way up) using with a single amp into a passive cross over to components compared to an active into three 100W amps?
> 1A) My understanding is that they would be the same.
> ...


1. It all depends on what power is getting to what speakers on what crossovers. Regardless of single amp or many. If the speaker is seeing the same signal from any amp, it will play exactly the same loudness and frequencies. If the signal is hitting a passive first before the speaker, it will be quieter. 

2.3.4.5.6. You need to do some reading on clipping and power ratings. You are overthinking things and over complicating things and just making a headache. Calm down, do some research.


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## Holmz (Jul 12, 2017)

Jscoyne2 said:


> 1. It all depends ...
> ...
> 2.3.4.5.6. You need to do some reading on clipping and power ratings. You are overthinking things and over complicating things and just making a headache. Calm down, do some research.


Thanks, duly noted.


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## Holmz (Jul 12, 2017)

Ok here is where I am at...

- I picked up some used Scanspeak D3000 beryllium tweeters.

Looking at scanspeak mids as well as the AudioFrog GB25s.
Mostly anything that is small, which other than the GB25s there is a not a lot.

And looking at TM65 for woofers... And maybe a small Sunfire sub.

But then it occurred to me that if I used a subwoofer that is capable to a higher frequency that I could possible just remove the need for a woofer altogether... Just. Running an extended sub, midrange and tweeter.

Maybe something like a single 8" or 10" morel and cross over the sub in the 300-600 Hz range as the GB25 should picks up by that point... And a scanspeak also is happy at the frequency.

So would running the cross over ~300 - 400 Hz and putting both the small tweeter and small midrange together on the dash result in good focus, or what frequency of cross-over point should be used to not have the subwoofer be apparent to the sound stage and focus?

Or is this seeming hair brained?


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## seafish (Aug 1, 2012)

Holmz said:


> Ok here is where I am at...
> 
> 
> But then it occurred to me that if I used a subwoofer that is capable to a higher frequency that I could possible just remove the need for a woofer altogether... Just. Running an extended sub, midrange and tweeter.
> ...


If you are able to mount the subs up in front of you , then it will not be an issue. However, frequencies over 80 to 100Hz are so are in fact localizable, so if your subs are behind you and you run the HPF much above that then you will likely mess up your sound stage and imaging.


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## Holmz (Jul 12, 2017)

Should I assume that the subs that go to almost 1-kHz are that way to reduce distortion in the edges of the pass a d and beyond so that the sub cannot be localised? 

Using a 12-dB cross over slope I am guessing 100 dB may be as high as I want to go before having them (it) start rolling off?

I am leaning towards a single 8" or a single 10".


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## Jscoyne2 (Oct 29, 2014)

Um. Subs dont go up that high. They should soley be used 90hz and down.

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## seafish (Aug 1, 2012)

Jscoyne2 said:


> Um. Subs dont go up that high. They should soley be used 90hz and down.
> 
> Sent from my SGH-M919 using Tapatalk






NOT saying that you should start playing your sub up that high, but IMO it has to due strictly with mounting location more then anything else. 
If the subs are mounted in fact up front, I don't see what the problem would be in playing them higher then 100 Hz if they are designed to be played higher and they blend well with the other front components.

The SI BMmkIV for example can play up to 300 Hz

A 12" woofer doesn't start beaming until 1300 Hz.

Maybe some members with front mounted subs can tell us what their HPF is, just for kits and shiggles.


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## Jscoyne2 (Oct 29, 2014)

seafish said:


> NOT saying that you should start playing your sub up that high, but IMO it has to due strictly with mounting location more then anything else.
> If the subs are mounted in fact up front, I don't see what the problem would be in playing them higher then 100 Hz if they are designed to be played higher and they blend well with the other front components.
> 
> The SI BMmkIV for example can play up to 300 Hz
> ...


Im building front mounted subs... well kinda. Sls 10s in the kicks so..close enough.

He named a sub that ive never even heard of. That doesn't mean its a bad sub but i cant tell him to run it that high. Plus this guy has alot of misconceptions about alot of things and the last thing we need to do is tell him to start using his sub up high when basically no one does that. Let him learn the basics before you push him into advanced theories 

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## seafish (Aug 1, 2012)

Jscoyne2 said:


> ...the last thing we need to do is tell him to start using his sub up high when basically no one does that. Let him learn the basics before you push him into advanced theories
> 
> Sent from my SGH-M919 using Tapatalk


No biggie, but if you actually read my post you'll see that I essentially told him NOT to cross them that high unless he was mounting them in front, which is why he started looking at 100 Hz HPF. IMO, there is nothing "too advanced" about that.

With that being said, what what HPF are you going to experiment with your front mounted subs ??


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## Jscoyne2 (Oct 29, 2014)

seafish said:


> No biggie, but if you actually read my post you'll see that I essentially told him NOT to cross them that high unless he was mounting them in front, which is why he started looking at 100 Hz HPF. IMO, there is nothing "too advanced" about that.
> 
> With that being said, what what HPF are you going to experiment with your front mounted subs ??


Idk yet. I need to cut some holes and see how low they will play. Natural roll off or distortion peak will determine x/o

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## Holmz (Jul 12, 2017)

seafish said:


> ...
> Maybe some members with front mounted subs can tell us what their HPF is, just for kits and shiggles.


Stroll around Europe before, pre-Copernicus, and asking people to opine about the roundness of the Earth would not lead one to the truth... Just an understanding the popular consensus of the group.




Jscoyne2 said:


> Um. Subs dont go up that high. They should soley be used 90hz and down.


technically some can go beyond 90 Hz...



Morel URL [url=http://www.morelhifi.com/product/ultimo-titanium-subwoofer/ said:


> ]Sorry, page not found - Morel[/url]
> Model - - - O Sz pwr Max SPL freq-Range
> 
> ULTIMO TI 102 2 1000 3000 86.1 10-900
> ...


Whether they should be crossed over higher is the question, which in the context of @seafish suggestion of mounting 'up front' "Might" make sense here.




Jscoyne2 said:


> ...
> He named a sub that ive never even heard of. That doesn't mean its a bad sub but i cant tell him to run it that high. Plus *this guy* has alot of misconceptions about alot of things and the last thing we need to do is tell him to start using his sub up high when basically no one does that. Let him learn the basics before you push him into advanced theories


Me or some other guy?
If it me then I am 'hear' to learn.
So bring the knowledge on, please.

I doubt I have room for even an 8" front mounted sub but I can make a dimensional wooden mock up... If it did fit, then crossing it over ~200 Hz would alleviate the need for a 6.5" woofer to fill in the ~100-200 Hz, where moony small mid-range speakers start kicking in.

So it seems a valid question to investigate.
Certainly it would be somewhat hard to stuff an 8"sub into a front pillar install, but pointing speakers at the knees seems also somewhat flawed.

Basically I want to keep the mid and higher frequency speakers that have impact on the focus close together... and then make sure that there is enough bass and subwoofer notes to have a sound decent. 

A small tuned port for a mid-range may help:

Audison 3" AV30: 250 Hz - Probably sealed, or infinite baffle?
GB25: 200 Hz - Probably sealed, or infinite baffle?
Scan Speak 10f: *125 Hz (Vented)*, 275 Hz (Sealed)

But it sounds like 200Hz requires the Sub up-front... maybe 125 Hz would work with a sub in the rear(?).
As the Sub technically goes 20-900 Hz. *This basic question of where to cross it over* becomes meaningful, and it sounds like if the sub was upfront, then one can go to 250 Hz with no issue.

*The other question is... Why are those 900 Hz subwoofers designed to go that high*... just because the can, or because they need performance that high in order to mitigate creating distortion harmonics that would have a 90 Hz cross over spewing out harmonics at 180, 270, 360, 450 Hz... that would be sonically upsetting/muddy/etc?


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## Jscoyne2 (Oct 29, 2014)

Holmz said:


> Stroll around Europe before, pre-Copernicus, and asking people to opine about the roundness of the Earth would not lead one to the truth... Just an understanding the popular consensus of the group.
> 
> 
> 
> ...


The problem is stereo. Around 250hz and up. The wavelengths start to get shorter than the cabin and thus they become left and right oriented instead of summing into a mono signal due to long wavelengths. If you have one subwoofer playing higher than that, you lose stereo separation. 

Ive never heard of anyone playing their sub up past maybe 125hz.

There is actually nothing wrong with pointing any speaker any direction as long as its below its beaming point and your within..say 90 degree of on axis.

A ported midrange may work. Its an interesting idea. 

Subs also dont play upper frequencies due to intermodulation. Midrange frequencies shouldnt be played in a speaker that is going to having large excursion. This is why we separate our midbasses and midranges.


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## Holmz (Jul 12, 2017)

Jscoyne2 said:


> ...
> Ive never heard of anyone playing their sub up past maybe 125hz.
> ...


I understand the dogma part, and I did stumble across something that spoke about intermodulation giving away the location of the sub... It was both intermods as well as clipping I think.
This link gives some mention about 200 Hz and the reasons, as well as 80 Hz. https://en.wikipedia.org/wiki/Sound_localization

In any case the reasoning behind why is more where I would like to focus. Subwoofers are outside of my experience, although I did put one behind a set of 30 year old speakers.


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## Holmz (Jul 12, 2017)

Time for the 6 month update.

Was going to collect the vehicle in December but a family member had me go to the US for tenting to then 'post operation;. Plus it was a bit warm, and still is.

So in Sept/Oct/Nov I had a frozen caliper replaced (had all 4 done, and 2 rotors). These are the same as Dodge Ram.

Also a new high output alternator to replace the 70A job. I think it was 140A.

And the AC.

And a bunch of other things like seals and bearing.

In the mean time I collected some speakers amp and head unit.

1 set is in some bookcase enclosures:
ScanSpeak 10f & SS Beryllium tweeters.

Another set for the dash.
Fonteck Ribbon tweeters (8-ohm) 
SS 12mu
SS 18wu
a pair of NVX 12/4-ohm subs

Amps
1) 2 channel 50W/channel for the tweeters
2) 4 channel 100W/Channel for the Mid/Woofers
3) 500W (2-ohm for the pair of Subs)

Extra Amps (bookshelf?):
4) 4 channel 40W/Channel off the back of a head unit
5) 2-channel 70W channel for woofer.










Need to work out whether the amps (1 and2) fit in the front, and then I only have to run RCAs back to the rear.

I collect it on a few weeks... And am headed towards going with a DSP.


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## GEM592 (Jun 19, 2015)

I like this thread


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