How to choose correct Drivers for DIY speakers? need advice

[kanwar]

almost all the theaters I have seen have trapezoidal or curved walls and ceiling. I am not denying it. But its to take care of reflections.

I know now you can't deny that classic theory of non-parallel walls.

Not true. As long as the walls are solid, there will be reflections and room modes will be formed. With different shapes, it will be at some other location, that's it. But your statement that standing waves can't form is misleading.

My statement is not misleading because in my experience i have measured a great deal of reduction in standing waves in a trapezoidal shaped room which was treated with absorbents and diffusers as compared to rectangular shaped one.

Here is what Dr. J.M. van Nieuwland has to say about the difference as per his research paper

Eigenmodes in non-rectangular reverberation rooms"

"The main difference between the rectangular and the non rectangular room is the fact that the axial and tangential modes do not exist, only the oblique modes are active. This results in a more regular distribution of the modes than one would find in a rectangular room with optimum dimension ratios. A regular distribution of modes avoids the occurrence of large dips or peaks in the frequency response curve. This led to the conclusion that non rectangular rooms are superior"




Have you done any measurements so far which can show us that non-parallel walls don't help?

The approach you say which is non-sensible has been pushed forward by renowned audio engineers worldwide, including Dr Floyd Toole of Harman. I don't think I can say likewise for non-parallel walls approach for small rooms use.

You again missed my previous posts regarding the Toole's white paper and in which he clearly stated that 4 subwoofers can uniform the response but at the expense of lower LF SPL which in my view is waste of resources and i find no need to repeat it how and why.

There is an excellent paper by Joseph R. Milner and Robert J. Bernhard which shows an investigation into modal characteristics in non rectangular rooms and their advantages over rectangular ones.

 

[navin advani]

Thanks Kapvin,
But after talking to you ,I started checking out projects similar to what you suggested..Anyone who wants to start DIY speakers can openly post in this thread.

There is a thread in DIY I believe where many projects are listed. Look for key words like Zaphaudio or Troels etc...

Guys - this is a bit off topic now
@Spirovious, again let me reiterate; based on what I understood of your room requirements, enclosure size limitations, your budget and your expectations from your sound - the Peerless nomex HDS and the Vifa XT19 make huge sense and should not require complex crossover work
@Manoj.p - love your signature

If I am going to redesign my speakers I will PM you. Right now I have a few other irons in the fire so I am thinking "not before,June". I have worked with Revelators before.

Oh BTW before you misunderstand me, I am not part of any audio industry in any country however I have been an interested bystander for almost 4 decades now.

How do find the HDS series. I measured a few using MLSSA at a friend's place and found too much variation from published specs. I am told they have improved QC of late. I would recommend SEAS's Prestige series instead.

I don't DIY nowadays like I used to in the 70s, 80s and 90s but am always interested in other's designs and products. Would love to see what you have done/are doing.

 

[spirovious]

How do find the HDS series. I measured a few using MLSSA at a friend's place and found too much variation from published specs. I am told they have improved QC of late. I would recommend SEAS's Prestige series instead.

I have heard that sometimes Seas drivers can sound a bit nasal.Is it so?

 

[Hari Iyer]

I have heard that sometimes Seas drivers can sound a bit nasal.Is it so?

This can be due to cross-over design error particularly in the phase region where it can sound nasal. Should not be a property of the driver though as per my personal view.

 

[kapvin]

How do find the HDS series. I measured a few using MLSSA at a friend's place and found too much variation from published specs. I am told they have improved QC of late. I would recommend SEAS's Prestige series instead.

the pair (830875) that I have are off spec .. but in a good "can be used in a smaller box" way. . but they are matched within 3% of each other.

I have not used MLS yet. so this is the simple small signal parameter checks and the FRD curves using an ECM8000 in a test box.

Of course, workmanship is not a Seas Levels, but I could not find an reason to complain on my pair. Not heard the prestige series, but this has a really clean sounding, extended midrange.

 

[kapvin]

I have heard that sometimes Seas drivers can sound a bit nasal.Is it so?

Metal cone drivers do have breakups, which need to managed by steeper slopes or notches or both. is that what you are talking about?

Not all Seas drivers are metal.

best wishes

 

[navin advani]

I have heard that sometimes Seas drivers can sound a bit nasal.Is it so?

I have used Prestige (Al) and Excel (Mg) series and not had a problem. I am told that the Nextel series is even smoother than the Excel but I was trading articualtion for smoothness and hence chose Excel.

Metal cone drivers do have breakups

Yes this was true in the 70s and 80s. By the 90s most companies are found ways to control the audible effects of breakup. The simplest and most effective was tuning the compund in the rubber surround. I cant find it but there were papers but both Audax and ScanSpeak (in the late 80s or early 90s) that covered this.

if I remember right I think Audax called their surround Norosex or something like that - oh wow I remembered it right here is a link I found to a 10 year old thread on this.
Hard vs. soft woofer membrane materials - diyAudio

Fact is ringing like we had in the old Aluminum cones drivers is a thing of the past.

 

[kapvin]

I have used Prestige (Al) and Excel (Mg) series and not had a problem. I am told that the Nextel series is even smoother than the Excel but I was trading articualtion for smoothness and hence chose Excel.



Yes this was true in the 70s and 80s. By the 90s most companies are found ways to control the audible effects of breakup. The simplest and most effective was tuning the compund in the rubber surround. I cant find it but there were papers but both Audax and ScanSpeak (in the late 80s or early 90s) that covered this.

if I remember right I think Audax called their surround Norosex or something like that - oh wow I remembered it right here is a link I found to a 10 year old thread on this.
Hard vs. soft woofer membrane materials - diyAudio

Fact is ringing like we had in the old Aluminum cones drivers is a thing of the past.

here's the FR and CSD of W18ex001 (Seas Excel Mg)

that stuff at 5khz?

and if we compare it with the HD graph:

that's third order - i.e a break up at ~1700hz.

but look how clean the sound is below that.

great for a 3-way. Or a 2 way with a brawny tweeter.

all data courtesy zaph..

 

[navin advani]

here's the FR and CSD of W18ex001 (Seas Excel Mg)

great for a 3-way. Or a 2 way with a brawny tweeter..

A 3 way makes sense. If you crossover at sat 300Hz or so to a 4-5" you are safe. Besides at 2K, beaming would start for a 7".

Do you have the CSD of the 4" and 5" (12cm and 15cm) Excels?

 

[Swifter9666]

Hello to all Audiophiles,

My Name is Arpit Goel from Noida, an auto fanatics, foodie, and IT professional.
I am building my own budget 3-way setup from DIY drivers for Swift 2018 AMT.
This car was earlier had with my father for office commute and he needs a google map that's why decided for hypersonic android HU.
After a few days, he took the VRS and the car came to me.

Current Setup

Hypersonic Android - SC9853i - IA Intel processor - bought for 24k from Prince ( not ready to sell it off for pennies) decided to retain it.
Hypersonic HU has lots of disadvantages in the sound stage like 2V preamp sensitivity, noise issues that will amplify after you connected with DSP.
Advantages: TPMS, front, and rear CAM connected with lots of other useful apps.

USB/Bluetooth DAC - Xduoo XQ-50 Pro DAC used for XMOS 208 USB input to RCA output
Bluetooth 5.0 LDAC input from Phone (as a dap) to DSP via Tosslink port

Midbass - Dayton RS-180-7-4 7 inch midbass crossed @ 70hz LR 24db to 350hz LR 24db

Full range - Dayton PS-95-8 point to source driver in A-pillar VAS is about 1 Liter and pods are designed like open baffled
LR 24db slope crossed from 350hz - bypass

Processor - Helix Dsp.3

Amplifier - Sony XM-GS4 4 channel 70w X 4 ( Powering midrange + tweeter (soon to be added) )
Amplifier - Clarrion ADP 4000 ( Powering midbass 100 W X 2 + Morel ultimo SC @ 2ohm 700 W )

Substage - Morel Ultimo SC 122 in ported enclosure tuned @ 32HZ 1.75 cu ft.

Big 3: Shock industries 0 Gauge (Got it from my friend)

Power wires: Rockford OFC RFK1D 0 Gauge ( battery to Distribution block )
Power Wires: KMH OFC tinned copper 4 Gauge ( distribution block to an amplifier)

Speaker Wire: Rockford ofc tinned copper 16 gauge ( got a sweet deal from Carplus Delhi)

Subwoofer Wire: Knuconceptz Kord speaker cable 10 Gauge OFC ultra flex

RCA - Custom made from Canare L-2t2s

All wires were wrapped in tech flex braided / loom tape and Ferrules for Clean installation.

I will post the pictures after the moderator approves my post.

PS: I need to add the tweeter for Clear high frequencies, thinking to cross above 8.5khz-11khz
A number of drivers I have selected according to match the frequencies and sensitivity with other drivers.
I don't need a very loud shrill or bright sound signature, I would love to listen a warm or a neutral sound signature and tonal response.


1. Dayton Audio AMT Mini-8 Air Motion Transformer Tweeter 8 Ohm
2. ScanSpeak Illuminator R3004/6020-00 1" Tweeter Small Ring Radiator
3. SEAS Prestige 27TFFNC/G (H1396) 1" Textile Dome Tweeter
4. Peerless XT25SC90-04 Ring Radiator Tweeter
5. SB Acoustics SB29RDNC-C000-4 Neo Magnet, Ring Dome Tweeter

I am just a Novice, let me know if there is any possibility of improvements in the current setup.

I would like to thank my dearest friend @bamaboy for building this complete setup from scratch in this lockdown period.

Regards,
Swifter9666

 

[samml]

Very well said spiro..

Even I am also on the verge of starting my own DIY sub with the help of the gr research sub driver that I am getting with the groupby. I am sure that I may not succeed 100% in my first attempt but this will not deter me to venture again. But I am sure I will do better atleast 10% compared to my earlier attempt. I believe DIY is not only to get something at a cheaper cost or well built one but to feel that its you who have created something out of nothing and gives you the satisfaction even if it fails.

Thanks.

Well said ...totally agree